Sour beer: Difference between revisions

[[Category:Beer styles]]

[[File:Passion-fruit-co-sour.jpeg|thumb|right|Renew Life Ultimate Flora co-sour with passion fruit and vanilla, courtesy of Dgallo on HomeBrewTalk|alt=Sour beer in a glass]]

Of all the ''Lactobacillus'' (Lacto) species, ''Lactobacillus plantarum'' has been a game-changer for making sour beer. It adds a nice flavor, it quickly produces a robust sourness at room temperature, and it's extremely hop-sensitive, all of which we can use to our advantage. This species of bacteria is the key to these modern methods because it can sour along with the yeast fermentation rather than requiring a separate or prolonged souring phase.

Similarly, modern isolated ''[[Brettanomyces]]'' (Brett) cultures combined with modern pitching strategies allow us to produce wonderful funky sour beer in the same time it takes to produce a normal ale! Additionally these methods are fully compatible with [[low oxygen brewing]], which enables the creation of beers with a unique amazing flavor unlike any that the world has ever experienced.<ref>[https://www.themodernbrewhouse.com//forum/viewtopic.php?f=2&t=2389 Seeking suggestions for LODO kettle souring.] The Modern Brewhouse website. 2021. Accessed March 2021.</ref>

==The Bacteria==

''Lactobacillus plantarum'' is the only species of bacteria that works with these modern souring methods.

* Swanson's ''L. plantarum'' capsules - on {{Amazon|B00EEACTO2}}.

* GoodBelly liquid - [https://goodbelly.com/where-to-buy/ in stores], capsules are on {{Amazon|B00USCCF5S}}

* Renew Life Ultimate Flora - on {{Amazon|B00H61ZBZU}} and in grocery and drug stores like [https://www.walmart.com/ip/RENEW-LIFE/105519384 Walmart]

* Lallemand WildBrew Sour Pitch - from [https://www.thebeveragepeople.com/wildbrew-sour-pitch-8-grams-details.html The Beverage People] and {{Amazon|B07J468VW1}}, for example

These methods are great for beginners and also more experienced brewers. The brewing process is basically the same as normal, except we add ''Lactobacillus plantarum'' to produce the sourness. These methods allow the production of beer within a normal time-frame for ales.<ref name="HBT">[https://www.homebrewtalk.com/forum/threads/fast-souring-modern-methods.670176/ Fast souring - modern methods.] HomebrewTalk.com forum. 2019–2020. Accessed 2020.</ref> It is extremely important to not add any hops before adding the Lacto because hops will prevent souring.

''Lactobacillus plantarum'' will not contaminate your other beer or "ruin" your equipment. Normal [[cleaning]] and [[sanitation]] procedures easily remove ''L. plantarum''. It is extremely hop-sensitive and therefore is incapable of souring your clean beers with hops, even if you were to directly add it.<ref>[https://www.homebrewtalk.com/threads/did-i-get-dead-lacto.664101/ Did I get dead Lacto?] HomebrewTalk.com forum. 2019. Accessed 2020.</ref><ref>Mike. [http://www.brew-dudes.com/berliner-weisse-recipe/570 Berliner Weisse recipe.] Brew Dudes. 2009. Accessed 2020.</ref><ref name="sui"/> These techniques actually have LESS risk overall of [[contamination]] compared to [[kettle souring]]!

# Pitch both the yeast and ''Lactobacillus plantarum'' (ideally from a starter).

Pitching bacteria without a starter has given inconsistent results, so we currently recommend making a [[Sour_beer#Lactobacillus_starter|starter for the Lacto]] before brew day to ensure the culture is healthy enough to sour the beer quickly.<ref name=HBT/><ref name=sui/>

Other alternative souring methods are to add straight [[lactic acid]], or use high amounts of [[acidulated malt]]. Subjectively these methods are less likely to make a "quality" beer, and so they won't be discussed here.<ref>[https://www.homebrewtalk.com/threads/damn-added-hops-to-gose.697667/ Damn!! Added hops to Gose] Homebrew talk forum. 2021. Accessed January 10 2022.</ref>

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[[Brettanomyces]] yeast takes sour beers to the next level by creating a complex and unique blend of fruity and funky flavors. With modern methods, these so-called "funky" sour beers with Brett can be produced on a rapid timeline similar to any ale. In a nutshell, this method is a post-sour, with highly fermentable wort pitched with both [[Saccharomyces]] and Brettanomyces from a starter. This process is designed to maximize flavor from both the Sacc and Brett, produce a good sourness quickly, and also reach full attenuation quickly so it can be packaged.

#* Minimize or eliminate the use of crystal malts and unmalted [[adjuncts]].

#* Mash around 149°F (65°C) for 2 hours. If [[mashing|step mashing]], include a couple of long beta rests.

At the time of packaging, the beer should have tons of flavor from all the ingredients, including the Brett. The flavor from the Brett will be mainly fruit-forward.<ref name="MTF-Brett">[http://www.milkthefunk.com/wiki/Brettanomyces Brettanomyces.] Milk the Funk wiki. Accessed April 2020.</ref><ref>[https://www.homebrewinguk.com/post/fast-red-100-brett-sour-no-boil-no-chill-12240117 Fast red 100% brett sour (no boil no chill).] HomeBrewingUK.com forum. 2022. Accessed January 12 2022.</ref> Additional aging (at room temp or possibly cellar temp) may bring out more of the funky character from the Brett, depending on the strain. We do not recommend aging in the fermenter because [[THP]] formation may be more likely and the risk of [[oxidation]] is increased.

Using Brettanomyces yeast carries some risk of contaminating future beers if you do not use proper [[cleaning]] methods. However, many brewers successfully use the same equipment for both "clean" beers and beers with Brett.<ref>[https://open.spotify.com/episode/2owYcSFS1rlT6JMMll8zYf Episode #008 - Mixed fermentation 101 with devin bell of Cash Crop Brewery and Brandon Jones of Yazoo Brewing Co.] Milk the Funk podcast. April 2019.</ref> (See [[Contamination]])

The starter volume only needs to be roughly 1% of the batch volume, so about 200 mL for a 5 US gallon (20L) batch.<ref name="Miller">Miller M. [http://sourbeerblog.com/lactobacillus-2-0-advanced-techniques-for-fast-souring-beer/ "Lactobacillus 2.0 – advanced techniques for fast souring beer."] Sour Beer Blog. November 2015. Accessed 2020.</ref> Larger is fine too.

# Add 100 g/L dry malt extract to a container such as an Erlenmeyer flask, a canning jar, or a small pot.

# Optional/recommended: Add 20 g/L [[calcium carbonate]].

# Optional/recommended: Add 2 g/L quality yeast nutrient.

# If a pot used for heating, transfer the wort to a sanitized jar or flask.

# Add ''Lactobacillus plantarum'' to the starter wort. Only a small amount is needed (e.g. the contents of one probiotic capsule).

# Swirl it occasionally. Try to mix in the calcium carbonate when stirring. It should be ready to use in about 24 hours. It should be hazy and have a aroma different from wort.

Lacto growth is inhibited by low/acidic pH. Calcium carbonate (a base) neutralizes the lactic acid and thereby helps maintain a high pH, increasing growth and yielding a much higher cell count.<ref name="Peyer">Peyer LC, Bellut K, Lynch KM. [https://onlinelibrary.wiley.com/doi/full/10.1002/jib.447 Impact of buffering capacity on the acidification of wort by brewing‐relevant lactic acid bacteria.] ''J Inst Brew.'' 2017;123(4):497–505.</ref><ref>Aeschlimann S. [https://eurekabrewing.wordpress.com/2015/05/18/evaluate-starter-media-to-propagate-lactobacillus-sp/ Evaluate starter media to propagate Lactobacillus sp.] Eureka Brewing blog. May 2015. Accessed 2020.</ref><ref name="Miller"/><ref name="sui"/>

The Lacto does not form a [[krausen]] like yeast does, but you may see some slight bubbling caused by the acid-base reaction. You will know the Lacto is alive if the starter is cloudy and has an aroma sort of like yogurt or iced tea (not just normal wort aroma in any case).

#* Optional: Add 2-3 g/L [[yeast nutrient]], ideally with amino acids and vitamins.

#* Ideally you should stop stirring it when it's finished growing since you don't want a lot of [[acetic acid]] production.<ref name="Preiss">[https://open.spotify.com/episode/5TmZGmVbF59le9L8kxDCaT Episode #000 - Richard Preiss of Escarpment Laboratories.] Milk the Funk podcast. December 2017.</ref>

* Ferment cool, closer to 65°F (18°C).

Many commercial "traditional" sour beers contain significant amounts of [[acetic acid]]. Acetic acid (vinegar) can add a nice tangy flavor and increase the complexity of the acid profile. This is easy to duplicate. You may simply add acetic acid at the time of packaging, using any vinegar product such as a commercial malt vinegar or homemade vinegar that you've produced. (See [[Vinegar production]])

With a 5% vinegar, adding 6–12 mL per liter of beer (23–45 mL vinegar per gallon) will add 0.3–0.6 g/L acetic acid to the beer, a good range for a nuance of complexity.<ref>Brungard M. [https://www.brunwater.com/articles/add-depth-to-your-sours Add depth to your sours.] Bru'n Water. Accessed April 2020.</ref> A [[bench trial]] is also a good option to determine the right amount for your taste. A lower amount may be needed if the product is very flavorful, such as balsamic vinegar.<ref name=HBT/> If using your own vinegar, you can do an [[acid titration]] to determine the concentration of acetic acid and thereby add a known quantity, which may be helpful for future reference.

 

Using the right process, there's no risk of "turning the whole batch to vinegar", even when using vinegar with a live [[acetic acid bacteria]] culture. Acetic acid production is an aerobic process, and therefore limiting oxygen exposure prevents additional acetic acid formation.

Pretty much any sour beer recipe found elsewhere can be adapted to use modern methods. Just follow a modern process with whatever malt, yeast, and hops the recipe lists. Just be sure to use ''L. plantarum'' as the bacterium. The one exception is that blended yeast/bacteria cultures (that contain [[pediococcus|Pedio]] and low [[brettanomyces|Brett]] cell counts) may not give good results in a short timeframe.

====Yeast====

Generally the Lacto contributes complementary flavors such as a nice lemony citrus tartness, with other notes such as berry, melon, peach, yogurt, smoke, and/or some slight earthy funk. Most of the desirable flavor from bacteria is expressed within a few days. There will be a bit more "complexity" that develops over the course of a couple weeks if you don't add hops before then. If [[brettanomyces|Brett]] is present, it often metabolizes anything that might be undesirable (such as [[isovaleric acid]]).<ref>[http://www.milkthefunk.com/wiki/Isovaleric_Acid "Isovaleric Acid."] Milk the Funk wiki. Accessed April 2020.</ref>

 

 

====Hops====

Anecdotally, anywhere from 0.5 to 1 oz per 5 gallons (15-30 g per 20 L) adds a nice hop character and prevents further souring.<ref>[http://www.milkthefunk.com/wiki/Hops#Inhibiting_Lactic_Acid_Bacteria Hops.] Milk the Funk wiki. Accessed May 2020.</ref><ref name="HBT"/> Hops do not necessarily kill the Lacto, they tend to only stop growth and metabolism, particular in lower amounts.<ref>Macrae RM. [https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2050-0416.1964.tb02001.x Significance of the use of hops in regard to the biological stability of beer: I. Review and preliminary studies.] ''J Inst Brew.'' 1964;70:340–344.</ref><ref name="sui">[https://open.spotify.com/episode/7D3LaDgmUVICWnTEQnr7jg Episode #007 - Lactobacillus microbiology with Dr. Bryan Heit of Sui Generis Brewing blog] Milk the Funk podcast. November 2018.</ref>

====Water====

Here's what we generally recommend for [[water]]:

* [[Brewing pH|Mash pH]] and [[Brewing pH|kettle pH]] should be targeted to your preferred values, generally around 5.4 and 5.1 respectively.

See [[Water]].

====Fruit, herbs, and other adjuncts====

* Recipe: [https://www.homebrewtalk.com/forum/threads/really-easy-fruit-sour.675345/ Really Easy Fruit Sour]

Michael Tonsmeire says "blending is one of the most important steps in sour beer production," but he also says "brewing sour beer forces you to accept many uncontrollable variables which influence the results."<ref>Tonsmeire M. [[Library|''American Sour Beers.'']] Brewers Publications; 2014.</ref>

As a general rule, weak acids have a stronger sour taste than strong acids at the same pH because they exist primarily in the undissociated state.<ref name="Dziezak"/><ref name="Neta">Da Conceicao Neta, ER, Johanningsmeier SD, McFeeters RF. [https://ift.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1750-3841.2007.00282.x The chemistry and physiology of sour taste — a review.] ''J Food Sci.'' 2007;72(2):R33–R38.</ref> For example, at a given pH, lactic acid tastes more sour than mineral acids such as HCl because there is more undissociated acid.<ref name="Roper"/><ref name=langfr/> The particular acid, the TA, and pH all definitely play a role in sour taste.<ref>Amerine MA, Roessler EB, Ough CS. [https://www.ajevonline.org/content/16/1/29 Acids and the acid taste. I. The effect of ph and titratable acidity.] ''Am J Enol Vitic.'' 1965;16(1):29–37.</ref> As pH decreases, the acid becomes more undissociated and imparts more of a sour taste, even if it's just because there's a reserve of protons that would ionized at the higher pH in the mouth. For example, the intense sour notes of lactic acid at pH 3.5 may be explained by the fact that 70% of the acid is undissociated at this pH, compared with 30% for citric acid.<ref name="Dziezak">Dziezak JD. Acids | natural acids and acidulants. In: Trugo L, Finglas PM, eds. ''Encyclopedia of Food Sciences and Nutrition.'' 2nd ed. Academic Press; 2003.</ref>

There is some disagreement among scientists regarding the mechanics of exactly how an acid causes a sour taste &mdash; whether it's evoked largely by the ''hydronium ion'' (H⁺ + H₂O ⇌ H₃O⁺) concentration (i.e., pH)<ref>Munger SD. Brady S, Siegel G, Albers RW, Price D, eds. ''Basic Neurochemistry.'' 8th ed. Academic Press; 2011:904–915.</ref><ref>

Valentová H, Panovská Z. Sensory evalulation | taste. In: Trugo L, Finglas PM, eds. ''Encyclopedia of Food Sciences and Nutrition.'' 2nd ed. Academic Press; 2003.</ref> or whether it's due to ''undissociated acid'' directly entering the taste cells before ionization.<ref name="Roper"/>

One hypothesis is that protonated (neutral charge) organic acid molecules traverse the cell membrane of taste cells, dissociate and acidify the cytosol, and thereby excite the cell.<ref name="Roper">Roper SD. Taste: mammalian taste bud physiology. In: ''The Curated Reference Collection in Neuroscience and Biobehavioral Psychology.'' Elsevier Science Ltd. 2016:887–893.</ref> Another hypothesis is that protons (and not undissociated acids) enter the taste cells and so depolarize the cell via sodium channels.<ref name="Scott"/><ref name="Neta"/>

Either way, all of the acid will give up its protons in the mouth due to the buffering effect of saliva; as the small amount of hydronium ions is neutralized in the mouth, more undissociated acid (HA) molecules ionize to replace the hydronium ions lost from equilibrium. However this raises an issue of sensory coding that has not yet been addressed, namely, how we can discriminate between sour and salty tastes if protons and sodium &mdash; both monovalent cations &mdash; activate the same receptors by means of the same mechanism.<ref name="Scott">Scott TR. Neural basis of taste, sour (acid) taste. In: Smelser NJ, Baltes PB, eds. ''International Encyclopedia of the Social & Behavioral Sciences.'' Pergamon; 2001.</ref> It is also unclear how taste cells transduce a sour taste because protons have diverse effects on cell membranes. It has been shown that acids in a single receptor cell may block ion channels, permeate ion channels, change intracellular pH, and alter transporter function. Although the variety of effects and potential targets are well recognized, until recently there has been little success in characterizing the molecular species involved in the transduction machinery.<ref>Izawa, K, Kuroda M. Chemical ecology, sour taste receptors. In: Mander L, Liu H, eds. ''Comprehensive Natural Products II.'' Elsevier Science; 2010.</ref>

 

*[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5486105/ "Antibacterial and Antifungal Activities of Spices."]

*https://embracethefunk.com/

*http://suigenerisbrewing.com/

*http://suigenerisbrewing.com/index.php/2020/11/22/probiotic-beer/

*https://www.tandfonline.com/doi/abs/10.1094/ASBCJ-58-0094

*Aneta Ciosek, Katarzyna Fulara, Olga Hrabia, Paweł Satora, Aleksander Poreda, Chemical Composition of Sour Beer Resulting from Supplementation the Fermentation Medium with Magnesium and Zinc Ions, Biomolecules, 10.3390/biom10121599, 10, 12, (1599), (2020).

*[https://www.mdpi.com/2218-273X/10/12/1599 Chemical Composition of Sour Beer Resulting from Supplementation the Fermentation Medium with Magnesium and Zinc Ions]