Fast Souring with Lactobacillus – Best Practices, Sensory, & Science
Hello Sour Brewers!
There are a number of brewing situations and recipe designs where both craft and home brewers would like to establish a nice clean baseline level of lactic acidity in their beers within a short period of time. In order to accomplish this, brewers turn to the Lactobacillus family of lactic acid producing bacteria because these bacteria are both easy to work with and readily available both as pure cultures and naturally on many base malts. In order to accomplish this goal, several methods have been developed to allow Lactobacillus to multiply and ferment lactic acid in the wort before it undergoes a standard fermentation by Saccharomyces (brewer’s yeast) or Brettanomyces. There are several process based issues that arise when attempting to give Lactobacillus sole reign over your wort, and for many brewers the results of such attempts have been lackluster or tainted by off-flavors. Despite this, many brewers have successfully used these methods to produce well-made sour beers with clean levels of lactic acidity.
The goal of the first part of this article is to review the various methods used to produce fast souring in beer and to discuss the best practices to follow when employing these methods. The second component of this article will be a discussion of how to analytically taste your beers in order to detect the various common off-flavors that can arise from fast-souring processes. Finally, a third element of this discussion with center on the science behind these fermentations, with a focus on the various unwanted bacteria that can compete with Lactobacillus. We will review why these bacteria produce the off-flavors that they do and why the best-practices reviewed in part one help to ensure that these bacteria are kept at bay.
Part 1 – Fast Souring Methods & Best Practices
The Sour Mash
Sour mashing is a process in which a typical mash is conducted, but is then allowed to remain warm for up to several days after an inoculation with Lactobacillus. This inoculation can come from either a pure culture of Lactobacillus, a Lactobacillus starter, or from the addition of a small portion of un-mashed base grain, which will naturally have one or more wild stains of Lactobacillus on its husks. After a certain level of souring has been achieved, the mash is sparged as normal and followed by standard boiling and cool-side fermentation practices. The benefit of this method is that Lactobacillus and any other bacteria present in the mash will be killed by the boil and only sanitized beer will move forward into fermentation equipment. The downside of this process is that, of the three methods we will discuss, this one is the most difficult to control and the one most likely to yield off-flavors. The following practices will help you gain the best results from a sour mash, but as we will discuss in Part 3, are not a guarantee of success.
Best Practices when Sour Mashing
- Conduct either a multistep or single infusion mash as dictated by your equipment or recipe.
- After your saccharification rest is complete, reduce the pH of the wort to 4.5 by addition of food grade lactic or phosphoric acid. This can also be achieved by the addition of acidulated malt (added after sacc rest). Acidulated malt drops the pH on average 0.06 to 0.1 per % of the total grist. This equates to about 7-10% of the total grist for any mash that has a pH of 5.2
- Verify your pH using a meter or test strips and adjust as needed before continuing on.
- Make sure to include a mash-out step which raises the temperature above 168° F for at least 10 minutes to ensure enzyme inactivation and a locking-in of your fermentable to non-fermentable sugar ratio.
- Cool the mash to below 120° F, then add Lactobacillus via a pure culture or by adding a small portion of un-mashed base grain. In any of these processes, using a pure culture is likely to yield more predictable results and reduce your risk of contamination by off-flavor producing bacteria.
- Remove oxygen from the mash tun by flushing the vessel with a layer of carbon dioxide or nitrogen. The mash tun should be sealed as best as possible to keep oxygen out during the sour mash. These inert gases can be bubbled through the mash itself or added via a port above the liquid layer as they are both heavier than oxygen and will displace it. If your equipment allows, a slow trickle of inert gas can be used to continually ensure an anaerobic environment during sour mashing.
- If possible, the temperature of the sour mash should be maintained between 112° to 120° F throughout the sour mashing process.
- Check the progress of your Lactobacillus fermentation via a pH meter every 12 to 24 hours. a pH around 3.6 generally equates with a tartness appropriate for styles like Berliner Weisse or Gose. A pH around 3.3 will be strongly sour, on par with many young lambic style beers. Keep in mind that at a pH below 3.4 to 3.5, some strains of Saccharomyces will have difficulty producing a healthy fermentation. In these cases it may be best to use a mixed or 100% Brettanomyces fermentation, as this family of yeast can remain healthy at pH levels down to and possibly below 3.0
- After your wort reaches the desired pH, raise the mash to 170° to 180° and sparge as usual.
- While a starting pH of 4.5 will generally eliminate the risk of bacteria that can cause food poisoning, use caution when tasting the results of a sour mash. Only a low pH and the presence of alcohol from yeast fermentation can ensure that your fermented product is safe to drink.
Sour Kettling
Very similar to the sour mashing process, sour kettling allows you to produce a sour wort that can then be boiled for sanitation before moving it into your fermentation equipment. Overall though, souring in the boil kettle allows for greater versatility and as a process can often be more easily regulated. This method also allows you to choose whether to kill the Lactobacillus before fermentation by yeast or to allow its continued activity in your aging beer. Sour kettling begins with the use of a completely standard mashing and sparging procedure. If you want to kill Lactobacillus before the rest of your fermentation, then you will perform the steps of sour kettling before the boil. Oppositely, if you want Lactobacillus to survive into your final product, then the boil is conducted before the sour kettling procedure.
Best Practices when Souring in the Kettle
- If choosing to boil at the end, the first step will be to adjust the pH of your wort to 4.5 using either food grade lactic or phosphoric acid.
- If choosing to boil before souring, make sure that your recipe either does not include hop additions or that those additions produce less than 10 IBUs in the finished beer. Too much alpha acid, or hop oils in general, will inhibit Lactobacillus and prevent souring via its fermentation. After boiling, adjust the pH to 4.5 as previously discussed.
- Cool the wort to below 120° F before pitching your culture of Lactobacillus or adding a sack of base malt to the kettle. As in sour mashing, pure cultures are more predictable and less likely to yield contamination by off-flavor producing bacteria.
- Flush the kettle with CO2 or Nitrogen gas and seal it up as best as possible. Consider scrubbing oxygen from the wort by bubbling inert gas through the wort for several minutes. As before, if your equipment allows, these gases can be slowly trickled into the sealed kettle throughout the sour fermentation to maintain an anaerobic environment.
- Maintain the wort at a temperature between 112° and 120° F, if possible.
- Just like sour mashing, check the pH of your wort every 12 to 24 hours.
- When the desired pH has been reached, either conduct a normal boil procedure, or if you have already boiled and wish to maintain Lactobacillus in your final beer, transfer to fermentation vessels using sanitary practices.
Sour Worting in a Fermentation Vessel
This third process assumes that you wish for Lactobacillus to survive and remain active in your fermenting and finished beer. On both a homebrew and commercial scale, it is best to use either pure laboratory-sourced cultures or cultures collected and maintained from starters which have proven to be free of off-flavors and aromas. Doing so, in combination with the other best practices discussed, will virtually ensure that your beer remains free of unwanted microorganisms and their off-flavors. For commercial brewers who cannot heat their fermenters , this process is identical to sour-kettling after a standard boil. When developing recipes for sour-wort beers, the alpha-acid level from hop additions must be restrained to less than 10 IBUs to prevent the inhibition of Lactobacillus.
Best Practices When Souring in a Fermentation Vessel
- Mash and Boil your wort as normal. During the boil, adjust the pH to 4.5 using food grade lactic or phosphoric acid.
- Cool the wort to below 120° F and transfer into a sanitized fermentation vessel. Ensure proper closed & sanitary transfer practices. I have run 110° F wort into glass carboys without incident, but I do not recommend that this be done routinely. It is far better to use a stainless vessel (for homebrewers, either 5 gallon Cornelius or half-barrel Sankey kegs work well) for these hot wort transfer and fermentation procedures.
- Purge both the wort and the fermentation vessel with carbon dioxide using either the line out on a corny keg or by using a sintered stone in other fermentation vessels.
- Pitch a pure culture of Lactobacillus or a Lactobacillus starter that is free of off-aromas.
- Maintain a fermentation temperature between 112° to 120° F. This can be achieved on the homebrew scale by the use of a ferm-wrap or other fermentation heating element and an insulated chamber such as a small chest freezer or a large insulated picnic cooler.
- As in previous methods, check the pH every 12 to 24 hours.
- When the desired pH is reached, cool the wort to the proper yeast pitching and fermentation temperature (between 45° to 55° F for lager Saccharomyces or between 65° to 75° F for ale Saccharomyces or Brettanomyces)
- Oxygenation at this point is very beneficial for the yeast and will not harm further Lactobacillus flavor development
- Pitch one or more Saccharomyces or Brettanomyces strains and proceed through a standard alcoholic fermentation from this point forward.
The ultimate goal of these three processes is the same: Produce a beer with a pleasant level of lactic acidity that is free of off-flavors in a short period of time. Lets now look at how to smell and taste the beer to detect the most common off-flavors that can arise from these fast souring methods.
Part 2 – Detecting Common Off-Flavors and Aromas and Understanding Their Cause.
As a brewer myself, it is always my goal to produce the best beer possible and it is from this perspective that I will launch into a discussion about off-flavors and aromas. That being said, I also know that, for many brewers who are first starting to experiment with sour beer, it can sometimes be difficult to distinguish between “bad funk” and “good funk” in these beers.
In general, Lactobacillus in isolation (the goal of these methods) should produce a far simpler flavor profile than produced by either traditional brewers yeast or the common sour beer yeast Brettanomyces. The primary product of Lactobacillus is lactic acid, which is a simple organic acid with a soft pleasant sourness. Common foods that feature this acid include Greek yogurt, kefir, sauerkraut, and sourdough bread. For the candy fans, the addition of lactic acid is what differentiates “Sour Patch Kids Extreme” from the classic “Sour Patch Kids”.
The fermentation of Lactobacillus will also give its beers a fairly subtle yet classic mustiness. This can smell a bit like a damp basement or the forest after a rainstorm. Another aroma commonly associated with Lactobacillus is a floury smell associated with sourdough bread and sourdough starters. These are light aromas easily overpowered by other additions to the beer such as hops or fruit. Additionally, the aroma and flavor compounds produced by brewer’s yeast strains or Brettanomyces will easily mask these characteristics. Despite this, I believe it is the presence of these non-acidic characteristics that differentiate beers actually fermented with Lactobacillus from those that have simply received a large addition of food-grade lactic acid. In my opinion, this latter process creates an inferior product which tastes somehow artificial.
Lactobacillus beers, when smelled at room temperatures, should not “stink”. This is especially true after a primary fermentation by Saccharomyces or Brettanomyces. Immediately after the Lactobacillus fermentation, it is common for the wort to smell:
- Musty or Floury (This would be considered “good funk”)
- Sugary, Syrupy, & Sweet (Because Lactobacillus produces only a minute level of attenuation in comparison to yeast)
- A little Buttery (Occasionally, because certain strains of Lactobacillus can produce diacetyl in their fermentation)
Lactobacillus species are divided into two groups, homofermentative and heterofermentative. Homofermentative species will only produce lactic acid during their fermentations. Alternatively, heterofermentative species will primarily produce lactic acid but can also produce ethanol, carbon dioxide, and acetic acid during their fermentations. I bring this up because, in very low levels, this acetic acid will add flavor complexity and should not be considered an off-flavor when using these species / strains. On the other hand, if there is a strong and distinct aroma or flavor of vinegar, this would generally be considered undesirable and is likely due to contamination of the wort by Acetobacter or other unwanted aerobic microbes.
If using a clean ale strain such as White Labs WLP001, Wyeast 1056, or Safale US-05 to ferment your wort after souring with Lactobacillus, you would expect the fully attenuated beer to have only a slightly musty and fruity aroma, as well as a clean and simple sour flavor.
Lets now take a look at the aromas and flavors that we do not want to detect in either the wort or finished beer:
- Parmesan Cheese, Rancid Milk, or Stinky Feet (Isovaleric Acid)
- Vomit or Bile (Butyric Acid)
- Fecal, Manure, Poopy Diaper (Aromatic Indoles)
- A strong presence of Vinegar (Acetic Acid)
- Bandaid, Liquid Smoke, Medicinal (Phenolic Compounds)

These batches of sour red ale undergo a sour worting process before being pitched with Saccharomyces and Brettanomyces.
When I am brewing a batch of sour beer using a Lactobacillus-first fermentation, the presence of any of these characteristics in my beer would lead to the batch being dumped. This is because I am not willing to spend time aging a beer with off-flavors in the hope that they will eventually become better. While personally I’m not willing to age such batches, three of the chemical compounds that are listed above can be either reduced or turned into flavor positive compounds by the yeast Brettanomyces. These compounds include isovaleric acid, butyric acid, and certain phenolic compounds. If you detect these compounds in very low levels, aging with Brettanomyces can eliminate them over time. However, if any of these compounds are intensely strong, it is best to dump the batch and review your processes. A good rule of thumb would be that if a flavor or aroma is off-putting enough that you would not drink several pints of the beer, then save your efforts and dump it.
When tasting your beer for off-flavors, it is sometimes very useful to drink another commercial example of the style that is known to be free of defects. This side-by-side comparison can really help to highlight flavors in your beer that you may not have otherwise noticed. Additionally, because strong lactic acid can be overwhelming to some taster’s palates, it can be useful to adjust your palate to intense acidity before analyzing the flavors in your beer. This can be done with a favorite bottle of strongly sour beer, a glass of water blended with lemon-juice concentrate, or by eating a few sour candies like Sour Patch Kids or Warheads.
A few more general tips for tasting and smelling your beers include:
- Pour the beer into a tulip glass or other similar aroma-promoting glass.
- Smell and taste the beer when it is at cellar temperature and at room temperature. Tasting or smelling the beer at cold temperatures will mask or reduce many flavor and aroma compounds.
- When smelling the beer, don’t be afraid to get your nose deep in the glass and take several good whiffs in a row. If your nose needs a reset, smell the skin of your clean dry arm for several seconds.
- When tasting the beer, pull some air into your mouth with the sip. This helps to aerate the sample and bring out both flavor and aroma compounds.
- Avoid tasting the beer after smoking, chewing tobacco, or eating any strongly spiced or otherwise potently flavored foods.
- If you are hunting for subtleties, don’t be afraid to ask for help. Genetically we all have a very wide range of sensitivities to different chemical compounds. A group of good analytic tasters can be the most useful tool in a brewer’s arsenal.
At this point we have covered both the best-practices to be used while fast-souring with Lactobacillus and how to analyze our beers for both positive and negative results. For the practical brewer, you now have all the tools you need to go forth and brew delicious fast-soured beers. However, for the inquisitive brewers, I will now wrap up this article with a discussion of the science behind these practices.
Part 3 – Fast Souring Science
Before jumping into a discussion of the organisms responsible for producing off-flavors in these fermentations, I need to mention a caveat to this information: Sour mashing, sour kettling, and Lactobacillus-only fermentations are relatively recent products of the American craft brewing community. There have been no detailed scientific studies directly looking at the organisms that are in play when these processes fail. However we can make fairly educated guesses as to the identity of the organisms involved based upon the chemicals and off-flavors that they leave behind. Many of these organisms have been studied in other food products or in other processes related to industrial brewing (practically all well-funded beer science has been performed in the arena of industrial lager brewing). Deducing the identity of the organisms that commonly compete with Lactobacillus in these fermentations allows us to re-engineer the process to reduce or eliminate the risk of these unwanted microbes.
Butyric Acid Bacteria
The easiest of these organisms to identify are members of the Clostridium family. These bacteria, especially Clostridium butyricum, are well known in the brewing industry as producers of butyric acid due to their propensity to infect sugar syrups in bulk storage containers. Clostridium are obligate anaerobic (they cannot survive in the presence of oxygen), endospore forming, gram positive, rod shaped bacteria which metabolize simple sugars to produce butyric acid. Butyric acid both smells and tastes like vomit, bile, and rancid milk or cheeses. This chemical is present in low doses in goat and sheep milk, butter, and parmesan cheese. It is also present in human vomit.
Clostridium, and other less common butyric acid bacteria, while requiring the same oxygen free environment that Lactobacillus prefers, cannot tolerate the same pH and temperature ranges as Lactobacillus. While Lactobacillus can comfortably thrive between 115° and 120° F, Clostridium dies at temperature above 112° F. Additionally, while Lactobacillus purposely acidifies its environment in order to outcompete acid-intolerant bacteria, Clostridium prefers an optimum pH of 6.3. As the pH of its environment drops near 5.0, Clostridium loses its ability to produce butyric acid, and at a pH of 4.7 or below, these bacteria become completely inactivated. These tolerances produce our recommendations to always pre-acidify the wort to a pH of 4.5 and maintain a temperature above 112° F when possible.
Indole Producing Bacteria
The presence of fecal aromas or flavors in a sour beer are an indication of an infection by bacteria known as coliform bacteria. These bacteria include families such as Citrobacter, Klebsiella, Enterobacter, and Escherichia and are found throughout nature. One species, E. coli, is a common bacteria found in the large intestines of most humans. This species also garnishes media attention from time to time due to its occasional ability to become pathogenic and cause a toxic diarrhea. Many species of these bacteria metabolize various amino acids to produce the chemical indole, a chemical which smells strongly of feces. These bacteria are rod shaped facultative anaerobes (preferring oxygen free environments but able to survive in its presence), which do not form spores. Certain groups of these bacteria can survive at temperatures above those preferred by Lactobacillus. Luckily for use, these bacteria, while able to survive a low pH environment, do not reproduce or metabolize well as the pH approaches 4.4. Therefore, our recommendation of lowering the pH to 4.5 before fermentation will help to prevent these bacteria from producing off-flavors in our fermentations.
Bacterial Production of Isovaleric Acid
Unfortunately, this narrative becomes more complicated when we look at bacterial sources for isovaleric acid. One definitive source of this off-flavor is metabolism of the amino acid leucine by a bacterium called Bacillus subtilis. This bacterium is present on human skin and is responsible, in part, for the production of foot odor. This rod shaped bacteria is known for its ability to form a protective endosperm which allows it to survive a wide range of environmental conditions. Luckily, this bacteria is an obligate aerobe (requiring oxygen to survive) and therefore can be prevented from affecting our sour fermentations when we maintain an oxygen free environment.
A second, and less controllable source of this off-flavor may be an interaction between a bacteria commonly found in yogurt cultures, Streptococcus thermophilus, and the very Lactobacillus which we are utilizing in our souring fermentations. Lactobacillus, in isolation, does not possess the metabolic enzymes needed to convert leucine into isovaleric acid. However, it seems that when S. thermophilus is present, it can potentially supply Lactobacillus with the chemical intermediates needed to perform this metabolism. The bad news regarding this interaction is the fact that S. thermophilus thrives in all of the same environmental conditions as Lactobacillus. Therefore the only process control that can prevent its influence in our sour fermentations is the use of good sanitation practices.

When working with wild harvested Lactobacillus, its always a good idea to test your results first using small starter batches.
This potential interaction is one of the reasons why I strongly prefer to use only pure cultures of Lactobacillus or starters which have already proven to be free of off-flavors. The temperatures of mashing will generally sanitize our wort and the process of boiling definitely will. (2015 Update: Always perform at least a 15 minute boil before beginning a fast souring process) As long as from these points forward only known cultures are introduced, there will be little to no risk of contamination. In fact, while I have used Lactobacillus first fermentations dozens of times, I have never experienced any of these common off-flavors in my beers.
Another reason to consider only using known cultures is the fact that bacteria can and do frequently swap genetic material, allowing certain strains to develop properties that they previously lacked. Therefore, the only way we can ever really know what is fermenting in our beers is to ensure that we put only the bacteria that we want into them. With that said, following the best practices outlined here will almost certainly yield positive results in your breweries.
Hopefully, this review has been interesting, informative, and helpful to brewers looking to develop a quick and simple acidity in their beers. These processes alone work very well when producing styles like Berliner Weisse and Gose, and can be very useful for establishing a baseline acidity in other more complex styles as well. As always, please email me at matt@sourbeerblog.com with any questions.
Have fun and brew sour!
Cheers!
Matt “Dr. Lambic” Miller
November 2015 Update: For those looking to expand their fast souring knowledge with techniques such as Lactobacillus pitch rate, starters, and recipe design, check out our new follow up article: Lactobacillus 2.0 – Advanced Techniques for Fast Souring Beer!
References:
Ghoddusi, Hamid B., Richard E. Sherburn, and Olusimbo O. Aboaba. “Growth Limiting PH, Water Activity, and Temperature for Neurotoxigenic Strains of Clostridium Butyricum.” ISRN Microbiology2013 (2013): 1-6. Web.
Goodwin, Jay, and Scott Moskowitz. “The Sour Hour / Episode 4.” The Sour Hour. The Brewing Network. Concord, CA, 20 Nov. 2014. Radio. (Features guest brewer Khris Johnson of Green Bench Brewing in St. Petersburg, Florida. Khris is the first brewer that I’ve heard make the direct connection between certain sour mash/sour kettle off-flavors and isovaleric acid)
Helinck, S., D. Le Bars, D. Moreau, and M. Yvon. “Ability of Thermophilic Lactic Acid Bacteria To Produce Aroma Compounds from Amino Acids.”Applied and Environmental Microbiology 70.7 (2004): 3855-861. Web.
Klocker, Alb. Fermentation Organisms; a Laboratory Handbook. London: Longmans, Green, 1903. Print.
Sakamoto, Kanta, and Wil N. Konings. “Beer Spoilage Bacteria and Hop Resistance.” International Journal of Food Microbiology 89.2-3 (2003): 105-24. Web.
Vriesekoop, Frank, Moritz Krahl, Barry Hucker, and Garry Menz. “125Anniversary Review: Bacteria in Brewing: The Good, the Bad and the Ugly.” Journal of the Institute of Brewing 118.4 (2012): 335-45. Web.
Zhang, Chunhui, Hua Yang, Fangxiao Yang, and Yujiu Ma. “Current Progress on Butyric Acid Production by Fermentation.” Current Microbiology59.6 (2009): 656-63. Web.
Zigová, J., and E. Šturdík. “Advances in Biotechnological Production of Butyric Acid.” Journal of Industrial Microbiology and Biotechnology24.3 (2000): 153-60. Web.
A brewing friend of mine is a fan of using apple juice as his starter for Lactobacillus; I think the idea is that it’s already a bit acidic, is all easily fermentable, and around 1.040 OG. I’m curious if you’ve had any experience using apple juice or just recommend sticking with a DME-based starter.
I haven’t personally used it but I don’t see any problem if using apple juice to test a strain of Lactobacillus for off flavor producing contaminants. If using the starter to grow up a larger culture for pitching, I would recommend mixing some basic yeast nutrient into the juice so that the bacterial cells have additional micronutrients needed for good growth and replication.
Good article, especialy liked the third part. One small point, you only mention Lactobacillus in general, where the choise of L. can have an influence on the choise of process. Where for example L.delbrueckii does not need or even like oxygen, L.brevis does.
Stamer JR, Stoyla BO. Growth response of Lactobacillus brevis to aeration and organic catalysts. Applied microbiology [Internet]. 1967 [cited 2014 Oct 26];15(5):1025–30. Available from: http://aem.asm.org/content/15/5/1025.short
In the “fast souring in FV” technique, what pH do you observe to lacto getting to? I’ve only attempted one batch along these lines, but I couldn’t get pH to drop lower than 3.4. I was using brevis at around 95F, so maybe that had something to do with it.
In my experience, when using Lacto in the FV, the pH will bottom out at 3.2 or 3.3 even after extended aging. In a fully attenuated and aged beer this pH level will be percieved as highly sour. These levels are due to the natural limits of the Lactobacillus. For even lower pH levels Pediococcus will need to be used in the process as well.
I think the temperature at which you perform your mash MAY also influence the final pH. The reasoning is that a higher mash temp will produce a wort with fewer fermentables for the lacto than a lower mash temp – fewer fermentables then result in higher pH and vise-versa).
I am in the process of testing this hypothesis (i.e. effect of mash temp on final pH) and will keep you posted on what I find. If you happen to have already done this, kindly share. Cheers.
At what pH do you typically chill your wort down to add the sacc or brett? You say when the desired pH is achieved, however, I heard you mention on BBR that the pH drops even more during the sacc fermentation/brett secondary and that it is good to not drop the pH too far in the fast souring stage. So, that said, if you were making a lambic style base or Flanders red style beer, when would you chill and add sacc? What pH?
If making a lambic or sour red base the wort can be chilled, oxygenated, and pitched with Sacc at any pH between 3.5 and 4.7 (or so). The more important thing for these beers is that the Lacto builds a strong colony within the beer because it will continue to sour as the beer ages. For a berliner weisse or a gose, I would take the pH down to about 3.6, this is a nice level of tartness for these styles, which generally would be drank fairly young, regardless of whether the Lacto is killed off in the beer or allowed to survive.
Thanks for information. Another question too. Do you prefer the Wyeast or White Labs lacto D? Or does it really matter? Also, do you prefer Wyeast or White Labs Brett Lambics? Or does it matter?
You’re welcome! My experience is almost entirely with White Labs cultures, but I wouldn’t expect the Wyeast Brett cultures to behave much differently. It is my understanding though that Wyeast’s Lacto is L. buchneri and that it is a bit slower to acidify wort than the White Labs L. delbrueckii or brevis.
I recently heard you on Basic Brewing Radio and the Sour Hour. I’m going to attempt another Berliner Weisse after my first one failed and wasn’t sour enough. I’m souring in a carboy but would like to make a lacto starter prior to pitching. However, I have several questions I haven’t been able to find answers on regarding this type of starter. 1. Should a stir plate be used? I thought lacto was O2 micro nutrient so this may not be necessary. 2. Does lacto flocculate like saccharomyces? I would like to decant my starter and pitch just the concentration of cells if possible. 3. I can usually grow up a good pitch of brewers yeast in a few days. How long does it take to grow up enough lacto cells for a typical 5 gallon batch? 6. Can you calculate and estimate growth rate of lacto like you can with saccharomyces? 7. Do lacto starters also need to be stepped up for larger batches?
I know, a lot of questions but any help or where I can find information on this subject would be helpful in me better understanding lactobacillus. Thanks
Thanks for the questions Jay! I’m going to do some research on them and write up a full post about Lactobacillus starters for our Ask Dr Lambic series.
Cheers!
Thanks! Looking forward to the article. Cheers!
Great write up! I’m looking to do my first Gose in the next couple weeks and this information has helped to answer a lot of my questions. I do still have a couple though if you have the time to respond. 1) After sour worting in a corney keg, do you transfer into a carboy before adding Brett or sacc for primary? Im wondering if just using the pressure relief on the keg periodically is going to be sufficient, or should I just get it out of the keg completely? 2) would you be concerned about sour worting in the same fermentation fridge you also ferment clean beers in? I was thinking as long as I didn’t have Brett in there, the risk of infecting my clean beers would be reduced, but I’m new to fermenting sours, so what do I know?Thanks for your help!
Cheers!
Jerad
Thanks Jerad!
I would transfer out of the corny keg and into a standard carboy for your primary yeast fermentation, both to allow more head space for krausen and to keep any pressure buildup from occurring. I have sour worted all of my sour beers in the same chambers that I ferment clean beers in. I make sure to scrub them down down good with a basic cleaner (like windex) in between batches but I don’t go to any extreme lengths and I’ve never had an issue. As long as you’re not doing an open-top fermentation there should be no problems.
Cheers!
Matt
Thanks for the quick reply Matt! I sort of suspected I should take it out of the keg to ferment. When I do so, should I be aerating at this point? I’m guessing the yeast need some oxygen (and nutrients?) but I am concerned about the lacto producing acetic acid.
Thanks Again!
Jerad
I would definitely recommending oxygenating the wort at the point when you pitch your yeast. I haven’t experienced any acetic acid when doing so. In theory an active pitch of either Sacc or Brett would utilize all of the oxygen before any appreciable acetic acid could be produced. Also only heterofermentative Lacto strains have the ability to produce acetic acid.
So you mention adjusting the pH of the mash down to 4.5 before adding any lacto. How important is that in getting the lacto to start quickly? And is there any rule of thumb for how much lactic acid to add if I don’t have a pH meter or titration kit? something like 1oz/5 gal?
Hi Joseph!
Pre-adjusting the wort pH to 4.5 is recommended to prevent the growth of certain off-flavor producing bacteria. It doesn’t directly affect the speed at which Lactobacillus grows. Unfortunately pH is affected by the buffering capacity of whatever solution you are measuring and this changes with each recipe depending on both the brewing water and malt bill. I wouldn’t recommend trying this technique without a pH meter or test strips. I personally think a pH meter is more than worth the investment for both sour and “clean” brewing, but if it’s not an option then I would focus on the other techniques mentioned here: keeping the wort above 112 F, paying close attention to sanitation, and using pure or known cultures of Lactobacillus.
Cheers!
Matt
Hey Matt,
Great info! I heard you on the Sour Hour and decided to check out the blog. I was wondering what kind of pitch rate you recommend for a sacc strain after a sour wort. I was planning on bringing the pH as close to 3.5 as I can and am going to pitch wyeast german ale. Should I go with the normal “million cells per mL wort per degree plato”?
Also, I didn’t have enough space in my 5 gal mash tun to do a mash out, do you see any issues with that? I figured this would be a fairly dry beer anyways. Thanks!
Hi Ryan!
Thanks for checking out the blog! I typically pitch the standard 1 million cells per mL per degree plato” for any pH wort down to around 3.5. If dropping below that you’ll have to be more selective with your strain or use Brett. I also increase my pitch rate at lower pH ranges to around 2 million cells per mL per degree Plato. As far as mashing out goes, if that step is skipped it can result in a thinner bodied more highly attenuative beer, although that is typically not a concern for Berliner Weisse or Gose.
Cheers!
Hi Matt!
A little while ago i brewed my first Gose using the sour kettling before boil technique. After mashing I put in a handful of grain, perged the kettle with CO2 and sealed it up. I left the kettle at room temps for 5-6 days before I boiled it.
Now to my questions:
My pre-sour gravity was 1.039.After souring, the gravity had fallen to 1.016, and after boil 1.022.
Fermented with US-05 down to 1.012.
What happened in the kettle to make the gravity drop that low? How much alcohol would be in my Gose? (under 2%?) Would this make my Gose “dangerous” as bacteria can live in it due to low alcohol content?
Did the lactic bacteria most likely produce alcohol? (and did I boil the alcohol off after? 60mins boil)
The taste is great, with good mouth feel, but it is very sour. As a sidenote, I checked the pH every day and it did not change much after 2 days of souring, but I had to leave it for 5-6 days due to other matters.
Hi Rasmus!
The drop in Gravity is most likely due to a wild yeast strain surviving in the batch. The other possibility is a heterofermentative Lacto strain that for whatever reason channeled most of its energy into alcohol production. Some of the alcohol produced will boil away but not all of it. If the beer is sour and has a pH below 4.5 it will be safe to drink even with an alcohol level below 2%. If it’s tasting good, I wouldn’t worry about it. Try boiling the wort both before and after adding your Lacto next time to make sure to kill off any potential yeast surviving from the mash.
Cheers!
Matt
I want to make a (Cucumber)Gose and a Berliner Weisse, my thought on this is to make this as a double batch(2X5gal) by making a mash, 60% Pilsner, 40% Wheat Malt, make this mash as usual, transfer to the kettle, then transfer to MLT, purge with co2, pitch lacto culture, then after 2-3 days when I get to 4.0pH, draw off 1/2 the wort, make this beer, then the next day or at around 3.6 make the Berliner with the remaining wort, your thoughts?
I think that sounds like a very good way to brew both recipes efficiently. I would recommend boiling the wort for at least 15 minutes before transferring into your MLT. Through a number of emails I’ve received looking to troubleshoot fast souring processes, the single factor that seems to lead to off-flavors (even in the presence of our recommended precautions) is a lack of some type of short boil between the mashing and inoculation step. Good luck!
Cheers!
Matt
Curious what off flavors you are concerned about between no-boiling between mash and lacto pitching? Is this purely sanitation, isovaleric prevention, or more to do with off gassing with a short boil? I’ve drained out of mash and brought to pasteurize at 170F for 15 minutes pre and post souring and didn’t have off flavors. Then again, at that point I could have just boiled the wort instead of bring it close to a boil.
Not sure if there are pros or cons to boiling vs not if left below 180F when pasteurizing to prevent DMS. Thoughts?
new to souring….If I kettle sour, will my equipment be infected with these bugs or will it be ok if I do a post or pre boil? Would like to start souring beer but don’t want to dedicate equipment just for that. thanks
Hi Nick!
Kettle souring is a popular method for that very reason, you can make a sour beer without worrying about transferring sour bugs into any of your equipment. You will not need a second kettle to do this, a short boil easily kills off Lactobacillus.
Cheers!
Matt
Hi Matt,
This article is brilliant and demystified the souring process for a newby like me. Very informative.
I have a question. With the process of souring in the corny keg. If you seal the corny keg with the wort inside and purge it, how do you then pitch the Lacto strain without then exposing the wort to oxygen? My apologies if this is explained and I missed it. I just couldn’t understand. Or, do you just purge without sealing the corny keg and pitch into that and transfer to another fermentation vessel? I’m confused.
I’d love to make a Flanders Red.
Cheers!
Smokey
Hi Smokey,
When souring in a corny keg, you should pitch your lactobacillus culture then seal up the keg. Once sealed, you can open the pressure release valve and run CO2 into the keg through the serving post (which will then bubble through the wort from the bottom of the keg). A minute or two of this should be enough to scrub any oxygen picked up during transfer and pitching. When souring in a keg I like to leave the pressure release valve open and place one of the foam plugs designed for use in Erlenmeyer flasks over it. Alternatively you can connect a blowoff tube to the gas post. Either way it’s a good idea to vent the keg since many strains of Lactobacillus are heterofermentative and can produce CO2. Thanks for reading the article and good luck with your Flanders Red.
Cheers!
Matt
Hello,
I just recently I have decided to intentionally tackle Sours, which I Brew using Parti-gyle so Sour’s will really fits well into the 3rd runnings. Which in the past I have produced a few call them ‘semi-sours’ unintentionally (Discovered was due to using Rose Hips and another was due to over ripe Bananas to the 2ndary BUT both were delicious, it was about week 4-5 that the sour started to appear.)
I have settled in on the Kettle Sour method would best in my setup since I have 3 Boil kettles but I am having a hard time sourcing larger quantities of the ‘Food Grade Lactic Acid’ and a good source of Lactobacillus, any suggestions?
Then do you or is there general guideline for required amounts:
1) of Lactic Acid to drop the ph, so if ph=5.2, what is the general required concentration of LA to gallon of wort to drop ph to <=4.5 levels? I know this depends on wort but just a good rule of thumb to go by.
2) of Lactobacillus, so say you have 5bbl wort, what is a good pitch quantity?
Thanks
Jerry
Well I have found the Latic Acid in quantity, Country Malt carries.
But now just a suggestion on the best Lactobacillus strain to use in ‘Sour Kettling’ technique and the suggested time to remain in kettle as appears is a variable depending on taste.
Thanks
Jerry
I’m attempting a kettle sour. I have made a 1.5L DME starter and pitched a vial of WLP677 L Debruekii It has been sitting between 100-120 for 4+days using a simple rigged light bulb in an pot set up. I havent seen any real action. There was a little very light foam around day 2 but that went quickly. I opened it up today and it smelled mostly like tart apple there is a noticeable amount of sediment on the bottom. Any thoughts?
Hi John,
When making a Lactobacillus starter you won’t see the type of activity or krausen formed when making a yeast starter. It sounds to me like visually and sensory wise everything is good to go. Let us know how the kettle souring goes.
Cheers!
Matt
Thanks, will do going to try it out this weekend. Doing a belgian rye brown “witbier” today for a zany belgian competion…
My plan is to mash then put the wort into a keg and pitch my starter. Then I was thinking I would purge the keg using the out to try and get more oxygen out of the wort. This sound like a good plan?
That is an excellent plan. I would suggest giving the wort at least a 15 minute boil before transferring into the keg to eliminate unwanted bacteria. Mashing temperatures typically will not fully sanitize the wort. Cheers!
Great writeup on the lacto souring process! I have a question for you though. I’ve done 1 sour mash (pitched raw grains) and it turned out decent, although it had a bit too much funk in it from oxygen exposure.
I’m currently trying out the sour kettle process and could use some help. I have about 7 gallons of 1.030 wort that I cooled to 110 degrees. I have my kettle pretty well sealed and hooked up to my temperature controller and heater set to 115. I pulled a sample from the valve yesterday evening (about 51 hours into the souring process) and I detected absolutely no sourness or acidic bite, just tasted like sweet wort. I made a 60ml starter 24 hours prior to pitching with 1 vial of WLP672. Any thoughts on why it might not be souring? Not sure if I should panic yet and maybe pitch another vial, or pitch some raw grains in there, or just wait it out another couple days…
Thanks!
Bryce
Bryce, I am also having this problem but on a much smaller scale. I’m on my third lacto starter right now using Wyeast 5335 and have had it going for 4-days right now and the pH hasn’t dropped a bit below 4.4. I would also like to take this starter and do some kettle souring as others have said they get sour wort in 24-hours or less but I’m just not sure how they’re doing it when I can’t even get a starter to sour!I’m beginning to think the culture’s I’m receiving are actually dead but unsure how to determine that or what even the life cycle of lactobacillus is. Growing a good pitch of lacto is a lot trickier then I expected and any help would be appreciated.
Hi Bryce and Jay,
I am by no means an expert in culturing Lactobacillus, although I do hope to have a basic guide for doing this repeatably written sometime this fall. I think it is worth mentioning that when creating a sour wort for beers like Gose or Berliner Weisse, strain selection is very important. There have certainly been a lot of folks who have had success getting their beers down into the 3.0 to 3.7 pH range with the strains from Wyeast and White Labs, but these strains do seem to be more finicky in doing so. This could be due to a number of variables affecting wort composition as well as conditions for the souring. There are several yeast labs producing strains that are more robust and reliable when it comes to producing fast and dramatic souring. Two of these that I would recommend would be Gigayeast’s Fast Souring Lacto and Omega Yeast’s Lactobacillus Blend. What I can say when using any strain, is that the pH drop, once it starts, will continue until the bacteria reaches is natural lower limit for the environment or is stopped by the brewer. In my experience, if a pH bottoms out in the low 4’s or high 3’s, it usually won’t continue to lower fast enough to be useful for a fast sour style like Gose or Berliner Weisse (if they will be boiled before adding yeast). These beers will generally continue to drop in pH into the mid to low 3’s if the Lactobacillus is not killed via boiling. This pH drop may take several months to occur. Also, if any strain of Lactobacillus has not begun to lower the pH within 24-48 hours, then the pitch was either too low in cell count or the temperature is too high for that particular strain. My recommendation of 115 F will work with about half the strains on the market but will be too high for some strains like Omega’s Lacto Blend. If a pitch seems to have been big enough but the pH does not drop within 24 hours, try lowering the temperature to around 95 F and give it another 24 hours. If no change occurs then you will likely need another pitch. Unfortunately, these strains are not nearly as domesticated as Saccharomyces strains of brewer’s yeast so some trial and error with strains, wort composition, and process are inevitable. I hope this is helpful. For more info on specific strains and their optimal temperatures, check out Milk The Funk’s Wiki page.
Cheers!
Matt
Thanks for your reply, more helpful information for my next attempt.
An update on my current Berliner. After 6 days of no detectable change I decided to pitch about 12 ounces of 2-row to see if the natural lacto would take off. Sure enough after 12 hours I could smell the lacto doing is thing. After 3 days I boiled it, cooled it and pitched US-05. The samples are surprisingly very clean with a nice tart lacto sourness.
Something that was not mentioned here is the calculated IBU of the beer you are trying to spot. My experience has been that many of the commercial lacto cultures perform poorly when the IBU is too high, even within the specs from the company. Omega lacto works really well, but again, you have to keep the IBU 5 or under. At that point I just keep it pretty much at nothing if I am pitching lacto after boiling.
I just skimmed through this, but thanks for the write up! I wish I’d found this earlier as it would have saved me from producing the disappointing sour worts I’ve attempted so far. But, now I’m really excited to give it a new go.
I am curious how long you end up having to age a beer if you don’t kill the lactobacillus after the quick souring, in particular if you pitch 100% Brett when the pH has dropped to the desired level. Does it take a few weeks or many months until the activity is done?
Hi Lucas,
This depends on a number of factors including strain selection and wort composition. A beer may reach a stable pH and attenuation within a few weeks or a few months. With Brettanomyces in the aging product, while these basic numbers may not change after this point, you may see flavor and aroma development / changes for much longer periods of time (potentially several years or more).
Cheers!
Matt
Hello Dr. Lambic!
I appreciate your very informative write-up! I’ve recently discovered and fallen in love with sour beers and started my first batch of gose last week following the sour-kettling process described.
Pitched 2 packs of GigaYeast Fast Lacto into 10 gal of 1.030 wort at ~105F and let it drop to ambient ~86F. Initial pH 5.6, 24 hours later pH 5.4, 72 hours later pH 3.5.
Although I smell some nice clean lacto in my samples, its hidden under a big butyric odor (parmesan cheese). I suspect contamination either from my sample valve not being fully sanitary and/or the pH remaining too high for too long, giving the ‘bad bugs’ a head start. Probably would have benefit from a lacto starter as well…
Anyway, I see how to troubleshoot these issues, but I’m curious about this: does lowering the pH to 4.5 with food grade lactic acid have an affect on the sour character of the beer? i.e. is there a noticeable difference in character by letting lactobacillus take the wort from 5.5 to 3.5 as opposed to 4.5 to 3.5?
Any insight would be appreciated!! Thanks!
Hi Brandon,
I have not been able to taste any difference in beers that have been pre-acidified to 4.5 versus those that have had the entirety of their acidity produced by Lactobacillus. Using lactic acid pre-fermentation allows the yeast to clean up some components of food grade lactic acid that can impact a beer flavor-wise if used to adjust acidity post-fermentation.
Another general point to keep in mind is that pH is a logarithmic scale. This means that the amount of lactic acid needed to change a wort or beer’s pH from 4.5 to 3.5 is ten times the amount needed to change its pH from 5.5 to 4.5. I bring this up to point out the fact that even in pre-acidified sour beers, around 90% or greater of their acid content is still achieved through natural bacterial fermentation.
Thanks for the great question!
Cheers!
Matt
86 might be too low for lacto – I hold mine to 115 to make sure other bugs don’t start…
Sour beer rules! There are lots of articles coming out about the positive neurological effects of good gut bacteria. So why not drink your yogurt in beer? Honestly I get a better overall feeling after drinking sour vs. anything else. I hope this continues to catch on. Been brewing sours now for 10 years, and not much else. Thanks for this excellent, informative website!
I recently bought two oak spirals and I’d like to keep using them from batch to batch, retaining some of the bugs similar to the way the breweries use funky oak barrels. But I didn’t have the guts to just move the oak from one fermenter to the next; I boiled it as I would anything else, to sterilize it. Did I really need to do that? Did I ruin the sourness in the oak? How do they do it in the big breweries? Thanks for any insight you can provide.
Hi Bill,
Your idea to move oak spirals from one funky batch to another is a great way to transfer a colony of Brettanomyces and bacteria, helping to develop a “house” sour character the way many professional breweries do. Unfortunately, the “sourness” of the oak is dependent on the survival of its colonists. By boiling and sterilizing the oak, you kill off the Brett and bacteria. Next time you use these spirals in a sour beer, just move them from one fermentation to the next without boiling.
Cheers!
Matt
Hi Matt, awesome article and I love listening to you on the Sour Hour!
Quick one, when kettle souring, what is appropriate cell pitching rate of lacto into the kettle?
Thanks man, keep up the fantastic research! 😀 Sour love from Ireland!
Thank you Dec!
There isn’t a lot of info out there regarding Lacto pitch rates, which is something I would like to change in the future. From my own experience, I usually see an appropriately fast souring (24-48 hours to get into the 3.x pH range) when pitching cell counts similar to those we use for yeast pitches: 1-2 million cells per mL wort.
Cheers!
Matt
That’s great, thanks Matt, cheers for the quick reply there too. Planning on attempting a little 1 UK BBL batch today after the normal brews are tucked away for the night.
I picked up some probiotics earlier today containing L. Acidophilus, Rhamnosus, Casei, Plantarum, Paraplantarum, Bulgaricus, Gasseri & Fermentum so will add the desired pitch at around 49 C to the kettle after a regular mash and sparge. I’ll let you know how it turns out.
Any undesirables in that mix actually??
Thanks again for your time
The probiotic blends tend to work very well for fast souring, but most of the strains in them won’t tolerate 49 C (120 F), when using one of those blends I would target 35 C (95 F) and just ensure that the wort gets a boil before pitching and cooling as well as to exclude as much oxygen as possible to limit the risk of off flavors. I also highly recommend pre-acidifying the wort to 4.5 before pitching. Cheers!
Yeah had planned to get it down to around 4.5 with some aciduated malt after a chat with another Irish brewer. I also came across a little tip for soaking some cara-pils or similar in the post boil to re-introduce some dextrins into the wort.
Would you recommend a pre boil over say slowly bubbling CO2 or N2 through the bottom of the kettle?
We’re about 4 hours or so off this brew 😀
Thanks a million for all your replies!
I do highly recommend a pre-boil. The pre-acidification is a big help to stave off unwanted bacteria but nothing beats a short boil. I’ve seen a big trend in my question emails that seems to point towards a lack of at least a short boil between mashing and adding Lacto cultures that results in a lot of unwanted bacterial growth as associated vomit or cheese aromas. Good luck!
Pre boil it is. Thanks a million again. Will post back taste results in a few days.
Thanks for all of your great information – I wanted to share two experiences and ask for some feedback. We are working on two fast kettle sour recipes for our new brew pub, a BW and a Gose. On our first pilot attempt I brewed the BW, ran off to the kettle, lowered the ph to ~4.5, purged with CO2, pitched two packages of Omega’s Lacto Blend, held at 105F and the wort dropped to 3.3 in about 18 hours, then followed it with the boil and sac pitch. The beer turned out well, however we felt it was a little one noted and had a bit of a dirty lactic sourness. The second attempt was the Gose this past weekend, same process however did a 15 minute boil before adding Lacto, and changed to two vials of WLP 672 brevis. The base recipe differed only in that we did not use any acidulated malt and therefore required more lactic acid to control pH in the mash. After 18 hours the pH change was negligible, dropped from about ~4.3 to ~4.0. Bought and added another vial of 672 about 30 hours after the initial pitch. 48 hours later, the pH was still around 4.0 and not much sourness detected. The wort was eventually dumped due to time constraints. My initial thoughts after reading your feedback above is that the pitch might have been too low, especially with the WLP over the Omega, and the lack of other bugs due to the 15 minute boil made the job even tougher. I also read someone mentioning 672 needing oxygen? I would like to make the WLP672 work, with the pre-boil, can you offer any advice for the 3rd try?
Hi Nick!
Your experiences and questions come at a convenient time because I have just finished authoring an article on advanced techniques for fast souring with Lactobacillus. The reason you experienced poor performance from WLP672 is because the two vials combined only give you a pitch of around 5 billion cells. The average cell count in an Omega Yeast Lacto Blend pitch is somewhere around 150 billion cells. I invite you to check out the new article and I would recommend producing a starter with the White Labs strain of L. brevis for your third attempt. Also, this strain can perform well in the presence of oxygen but I do not feel that it is necessary for the strain to properly sour wort.
Cheers and Good Luck!
Matt
Hi Dr Lambic,
Firstly, thank you for two wonderfully extensive articles surrounding fast souring. Some
I’ve done three batches now of fast sours, firstly with WL Lacto Brevis, which seemed to work well but obviously had some sacc in and actually had around an 80% attenuation as well as getting to 3.4ph.
Most recently I used L.Plantarum probiotic pills which was super fast at souring after a pretty healthy pitch. The 2 split batches I pitched into got to 3.3 and 3.2ph in 20hrs.
A quick question, are there any good clean sacc yeasts that can handle this type of PH? For this one I pitched a lot of US 05 and hoping for the best, but would love a few options.
Thank you Josh!
It seems that when looking for clean fermenting Sacc yeasts that the American ale strains (US05, WLP001, Wyeast 1056) do tend to be able to handle these pH levels if pitched at above average rates (I usually shoot for approximately double what the yeast calculators recommend). Additionally most saison strains are known to handle these pHs well if you are going for farmhouse style sours. Lastly, most strains of Brett and the “Brett-like” WLP644 Sacc trois will ferment healthily at low pH ranges. Beyond this I’m sure that there are a number of strains that can work but will work best if used very fresh/healthy and at larger than average pitch rates. There’s a lot of experimentation to be done in this area.
Cheers!
Matt
Thanks Matt, appreciate the reply. US-05 with a big pitch worked this time. Will try out a few others that you mentioned too.
Dr. Lambic,
I am going to pitch a starter of a Lacto into a corny keg of wort. When you purge with c02 you mentioned that you use the line out rather than the line in? Is this to assure that the c02 is purging any remaining o2 in the wort completely out? Also after your wort reaches desired ph in the keg do you transfer the beer into a carboy for normal sach. fermentation or rather just pitch your sach. strain directly into the corny keg and fit a blowoff valve?
Hi Jake,
Yes, I prefer bubbling the CO2 through the wort to scrub out extra oxygen from the wort as well as clearing out the headspace. I generally pitch the Sacc. strain into whichever fermenter I’ve used for primary souring without transfer. If aging on Brett, I will transfer the wort off of a large Saccharomyces yeast cake before pitching Brett.
Cheers!
Matt
I brewed what will be an 8 gallon batch of Berliner Weiss Saturday (3 days ago). It is about 10.5-11 gallons now (pre-final boil), I did boil it for a few minutes before chilling (no hops, etc). Saturday night, I pitched 2 – 8 0z tubs of non-fat Greek Yogurt with L. Bulgaricus, S. Thermophilus, L Acidophilus, Bifidus, & L Casei cultures. I had put half of one of the tubs in a starter the day before. After 2 1/2 days I am perceiving some sour, but I am not sure it isn’t the 8 oz of acid malt in the mash. I have been keeping it at 120 degrees. Did I kill the cultures? Should I lower the temp? Add more cultures? I tested the PH with strips and it is still around 4.0.
FYI – I have come up with a good way to keep the temp controlled for the bacteria to grow. I use my boil kettle as the vessel, since I will be doing a full boil later.
I electric brew and have temp sensors on my HLT and boil kettle. After some thought I decided to use my old immersion chiller as an immersion heater. I was afraid that if I used the boil kettle’s element the element heat would kill cultures in anything that it touched. So, with 125 degree water in my HLT, I use a chugger pump controlled by the sensor in my boil kettle to circulate water through the immersion chiller to keep it at a constant 120 degrees. It works great, although it does run the pump for a few seconds every minute and with my bedroom above my brewery, I do get a little flak from the wife.
Hi Tim,
In most cases 120 F will not kill Lactobacillus strains that prefer lower temperatures but it does inhibit them from metabolizing and growing. I would recommend lowering your temp to 95 F and recheck the pH in 24 hours. If no further change has occurred, repitch a new culture. Good luck!
Cheers!
Matt
Thanks, I will give it a shot.
Thanks so much for the forum post.Much thanks again. Really Cool.
Thank you for reading! Cheers!
Hi Dr. Lambic, Glad I found this site through the Sour Hour. Thanks for the post. I have a question. I have started a wild bacterial culture from some cherries I grow on my property and I am one week into cultivating it. Today was the first time I opened it up and took a whiff…
My first observation was that it smelt of fecal, or Indole. After thinking about it a little my second thought is that the aroma may be more vomity/Clostridium-y. I cannot quite be 100% as these are not aromas I’m well acquainted with. The only real reason I attribute it to Indole is that it is an aroma i have picked up in small doses in other commercially available sour beers in very small doses.
I’m wondering what my next steps should be with this wild starter to try and DIY isolate out the bad bacteria? From reading this article it seems that perhaps the next starter wort I make I should make sure it is 4.7PH or lower? Will this make a noticeable difference? Or should I go with my gut and let it age and see what happens?
Thanks in advance.
W
Hi Wesley,
Its hard to say exactly what may be growing in the wild collected culture. I wouldn’t recommend trying to isolate specific strains from it unless your’e versed in streaking plates and using sterile lab technique. I would recommend making a starter wort that has been acidified to pH 4.5 and culture a new starter from the cherries in order to avoid both Clostridium and Enterobacter species. As for the initial starter, If you’re interested in trying it in a beer, I would reserve it for addition with or after an initial fermentation of Sacc, Brett, or both. Wild cultures (even those producing some funky off-flavors) can add a unique element when you add them into an already fermented sour beer and allow that beer to further age.
Cheers!
Matt
Hi Dr. Lambic, my idea is to make a pseudo lambic doing so:
Lambic recipe, it means also to have Turbid Mash
Kettle souring to a ph of 3.3
Boil and adding suranne hop (low aa will give to pedio the ability to grow)
Primary in with a neural yeast (notthingam @ 16° celsius)
Secondary in a oak barrel with belgian mix
bottling after 8 months
What do you think about?
Sorry for my english
Hello Lorenzo,
Since you are planning for a longer aging time and employing a turbid mash, I would back off on the degree of kettle souring that you have planned. I would personally shoot for a pH of 3.7 to 3.8 to establish some baseline acidity and then let the Pediococcus continue to lower the pH slowly with time. In my experience, starting with a slightly higher pH will allow your Brett stains to develop a more complex assortment of flavors that are more representative of traditional lambic beers. Also, you may find that when using a turbid mash, the beer is ready for bottling after a bit longer than 8 months: more likely in the 12-18 month range.
Good luck!
Matt
Dr. Lambic,
I would love to make a Berliner Weisse using the kettle souring method. However, at this point I do not have the means to keep the wort above 100F. Is it possible to create this beer at 75F if you wait longer, or should I wait until I can invest in a temperature control system? If it is possible, what process changes are important to prevent off flavors with the lower souring temperature?
Thank you!
Hi Aaron,
It’s definitely possible to make a Berliner Weisse without keeping the wort hot. The easiest way to do this is to use Omega Yeast’s Lacto Blend. This grouping of strains can be pitched at around 95 F and allowed to slowly cool to room temperature. Most people can achieve an acidification down to around pH 3.3-3.4 within 24-36 hours using this method. If you choose another strain, many will still acidify slowly at lower temps, but the process can take many days. The biggest issue with extended souring times are risk of contamination by either unwanted bacteria or wild yeast. To prevent bacterial contamination, make sure to pre-acidify the wort to pH 4.5 at the end of the boil. To avoid wild yeast contamination, try to reduce any exposure of the souring wort to the air (after cooling below 120F, keep the lid on the kettle as much as possible or if transferring to another sanitized vessel, use hoses and closed transfer processes). Good luck!
Cheers!
Matt
Hi, wondered if I could trouble you with a question. I am making a Berliner, my 2nd sour. wyeast 5335. i bought a honey container heat blanket and wrapped boil kettle in sleeping bag. I’m at 4 days and dropped from 4.5 to 4.1. I checked the temp today and it was at 134F. I removed the blanket and am now wondering if i have enough live bugs to continue or if i should repitch some probiotic capsules or whatever i can get locally. i wasn’t sure if 134 would kill the lacto or if it should take off getting down 15 degrees or so.
Hi Brendan,
Typically anything over 120F for an extended period of time will kill most Lactobacillus strains. I would suggest pitching some fresh capsules and keep the temperature between 90-100 F (a more appropriate temp for the strains most commonly included in probiotics). Cheers!
Out of curiosity (and partly due to the fact I’m cheap), I picked up a packet of wyeast 5335 and if I kettle sour and fill a sterilized ball jar with pre-boiled wort filled with lacto can I save this in the fridge to use in my next sour brew? Any concerns with infection?
Thanks
Matt
Hi Matt,
This is definitely possible and is similar to the method used to keep a Lactobacillus culture going at many commercial breweries. The most challenging aspect to the practice is keeping unwanted yeast out of the culture. If yeast get into the culture they will outcompete the Lactobacillus and begin to reduce to speed and effectiveness of any fast-souring process.
Cheers!
I am wanting to start a Wort sour in the FV. This is a small scale commercial beer. My proposed process is to mash and boil as normal, transfer to a fermenter at approx 100 degrees F, reduce pH to 4.5 and then pitch a volume of good belly product. My reasoning for good belly is that this will be a 2.5 bbl batch and I am looking to test this method out not wanting to put too much money into a process that isn’t proven.. I do not intend to boil post souring rather just reduce temp and pitch sacc.
I guess my question would be if this sounded like a safe process and a safe source of lacto given this method.
Hi Jeff,
Your process will work just fine and will be safe. Goodbelly contains a fairly aggressive strain of Lactobacillus plantarum. In my experience, this strain can continue to sour the beer once Saccharomyces has been pitched. Therefore you may not want to target as low of a pH before pitching Sacc as one would target when doing a boil that kills the Lacto. Playing around with the pitching times and rates will help you dial in the acidity of the finished beer. Regardless, I don’t expect you to have any problems using your plan.
Cheers!
Hello Dr. Lambic.
After a few years of brewing “regular” beers in larger quantities (20Gal batches), I have decided to throw myself at kettle souring using a new dedicated 5 Gal kettle.
My intention is a basic BiAB recipe and to follow your douring recomendations.
Since I live in Canada, and fall is approaching, I may have a hard time maintaining temperature for Lacto culture. I may try to get my hands on a heat belt, but my temp might be in the room temperature range.
I should be be using OYL605 since it grows at lower temps, but my main question is about the yeast.
Once boiled (60 m or so) and cooled, transferred to carboy, I would add some OYL091 Hornindal Kveik. Is this a good yeast, or should I perhaps stick with good ol’ reliable US-05?
Also, I intend to “bubble” my wort with a shot of co2 with a tube, and covering with cellophane. Does that sound right
Thanks for your time, and I have to admit, brewing sours makes me a little nervous.
Hi Alain!
When using OYL065 or other strains of L. plantarum, my recommendation is to pitch the bacteria at 95-100 F, wrap the kettle in a blanket or other insulation, and then let it slowly drop to room temperature. The Lacto will acidify fastest in the 85-95 temp range but will continue working at lower temps as well. In most cases with this approach you will be able to hit a pH of 3.4-3.6 within 24-48 hours. After Sacc fermentation, expect the final pH of the beer to be around 0.2 points lower than the pre-boil / pre-yeast fermentation.
Kveik strains in general work well in acidified fermentations / mixed culture sour beers. I think OYL091 should work well in this application.
Lastly, the steps to remove oxygen via CO2 bubbling & cellophane wrap are generally not necessary when working with pure cultures of Lactobacillus in a clean environment and clean brewing kettle. Those recommendations apply when inoculating with grain or other sources of unknown bacteria strains.
Good luck with brewing your first sour batches! No need to worry, just keep your brewing and fermenting areas clean and you should have no problem brewing regular beers and sour beers in the same space.
Cheers!
Matt “Dr. Lambic”
Thanks for your answer. This is great info, and I’m glad I came across this blog!
A quick follow up question. I’d rather use a pure dose of lacto in a 5 gal. Is the content of the pack enough for this quantity ( can’t seem to find content of the pack online), or will I need a culture?
If so, so be it, I’ll need to get my hand on a stir plate/Erlenmeyer:)
Thanks again.
A
Hi Alain,
The contents of the Omega Lacto pack should be more than enough for a 5 gallon batch.
Cheers!