Changes

'''Sour mashing''' is a technique for adding acidity to a beer before primary fermentation begins. This is accomplished by the introduction of lactic acid bacteria into the mash after the completion of the starch conversion. Performing a sour mash is similar to [[Category:TechniquesWort Souring]]in that both techniques involve acidification of unfermented wort with lactic acid bacteria before primary fermentation. Many sour brewers prefer [[Wort Souring]] (which includes ''kettle souring'') due to having more control over off flavors produced versus sour mashing. <blockquote>"''Mixed culture fermentation for sour beers produces one thing, and (kettle souring/sour mashing) produces another thing. If you’re going to make a malty red ale that is kettle soured, don’t call it a Flanders Red. Honor the tradition.''" - Sean Burke of the Commons Brewery, Kettle Souring Presentation, CBC 2015.</blockquote> ==Methods of Sour Mashing==Sour mashing procedures fall into the normal all-grain brewday process after completion of saccharification, and any other desired mashing rests, and before the separation of the wort from the grain. After the normal saccharification rests and a mashout to 170+ F (76.7+ C) to denature enzymes in the mash, the mash is cooled to approximately 120 F (48.9 C). At this point the mash is more or less pasteurized from the hot temperatures of the mash. In order to reintroduce bacteria into the mash it is inoculated with lactic acid bacteria. This may be accomplished by addition of a pure culture of ''[[Lactobacillus]]'' or, more commonly, by the addition of a small amount of unused malt, which has ''Lactobacillus'' in addition to other bacteria and yeasts on the husks (see [[Grain#Malted_Barley|bacteria found on malted grain]] for more information). To help favor the growth of ''Lactobacillus'' over the other unwanted microbes, it is important that the mash be kept anaerobic and incubated warm (ideally 113-120°F/45-48.9°C) throughout the duration of the sour mash. This can be accomplished by purging the headspace with CO2 (some breweries go so far as to bubble CO2 through their mash while it is cooling, and periodically throughout the souring time) and covering with saran wrap at the liquid-air interface to eliminate air contact. The favoring of ''Lactobacillus'' over spoilage microbes can also be supported by dropping the initial sour mash pH by methods such as the addition of acidulated malt, lactic acid (preferably), or starter wort from a ''Lactobacillus'' culture.

== Introduction ==Sour mashing is may be conducted on the entire mash, or may be conducted on a portion of the mash. On a homebrew scale, sour mashing only a technique for adding acidity to portion of the grist can easily be accomplished by conducting a beer small stove top mash before primary fermentation beginsthe planned brewday. This is accomplished by pre-soured portion can then be blended in with the wort collected from the introduction normal mash of lactic acid bacteria after the completion of remaining grist during the mashing process. Sour mashing is similar to [[Sour Worting|sour worting]] in that both techniques involve acidification of unfermented wort with lactic acid bacteria before primary fermentationbrew day.

== Methods of sour mashing ==Sour mashing procedures fall into the normal all-grain brewday process mashes typically last between completion of saccharification, roughly 12 hours and any other 3 days. After the mash has reached the desired mashing rests, and separation of acidity the wort is separated from the grain. After the and boiling and fermentation are carried out as normal saccharification rests and a mashout to 170+ F (76.7+ C) to denature enzymes in the mash, the mash It is cooled to approximately 120 F (48.9 C). At this point the important that wort from a sour mash is not consumed, especially if it was inoculated with lactic acid bacteria. This may be accomplished by addition of a pure culture of ''grain, because pathogens have been found to grow in wort soured with grain (see [[LactobacillusGrain#Malt_Inoculated_Wort|Malt Inoculated Wort]]'' or, more commonly, by the addition of a small amount of unused malt, which has ''Lactobacillus'' in addition to other bacteria, yeasts, and molds on the husks).

To help favor the growth of Some professional brewers have reported stuck or slow sparges when performing a sour mash. This generally isn''Lactobacillus'' over these other unwanted microbes, it is important that t a problem on the mash be kept anaerobic homebrew scale. Adding rice hulls and incubated warm (generally 100-120 Fresetting the grain bed will help resolve the issue <ref>[https:// 37www.8-48facebook.9 C) throughout the duration of the sour mash. This can be accomplished by purging the headspace com/groups/MilkTheFunk/permalink/992202820807932/?comment_id=993343157360565&comment_tracking=%7B%22tn%22%3A%22R0%22%7D Conversation with CO2 (some breweries go so far as to bubble CO2 through their mash while it is cooling) and covering with saran wrap at the liquid-air interface to eliminate air contactprofessional brewer Anthony Accardi on MTF. The favoring of ''Lactobacillus'' over spoilage microbes can also be supported by dropping the initial sour mash pH by methods such as the addition of acidulated malt, lactic acid, or starter wort from a ''Lactobacillus'' culture]</ref>.

Sour mashing may be conducted on ===Unwanted Microbes===Due to the entire mash or may be conducted on a portion wide variety of the mash. On microbial species typically added to a homebrew scale, sour mashing only a portion mash from the addition of unused grains of malt after the grist can easily be accomplished by conducting a small stove top mash before the planned brewdaymashing process, unwanted microbes such as ''Clostridium spp''. This pre-soured portion can then be blended take hold in with the wort collected from the normal a sour mash of the remaining grist during the brew dayand produce off flavors such as [[Butyric Acid|Butyric acid]] and possibly [[Isovaleric Acid|Isovaleric acid]].

Sour mashes typically last between roughly 12 hours and 3 days. After Should the sour mash has reached display prominent character of these spoilage organisms, such as rancid/vomit/fecal aromas or moldy patches, it may be advisable to not use the desired acidity sour mash. If the wort sour mash is not acidic enough it is separated from possible for human pathogens to be present in the grain mash (over 4.4 pH), and it may not be advisable to taste the boil and fermentation are carried out mash, especially if noticeable spoilage aroma is detected. [[Wort Souring]] is generally not as normalsusceptible to these spoilage organisms.

Some professional brewers have reported stuck or slow sparges ==Microbiology and Biochemistry==The buffering capacity of the mash is higher than wort due to the grain material. This has a positive affect on the growth of lactic acid bacteria. Peyer et al. (2017) found a slight increase in cell growth of ''Lactobacillus'' when performing incubated in a sour soured mashversus when souring in wort. This generally isn't However, due to a problem on much higher concentration of sugar content and buffering capacity of the homebrew scalesour mash versus plain wort, less lactic acid was actually produced. Adding rice hulls This study also found that sour mash beers have almost four times as much acetaldehyde as the co-fermented and resetting kettle soured versions, although this was speculated to be caused by the grain bed will help resolve oxidation of ethanol in the issue sour mash, which converts alcohol back into acetaldehyde <refname="peyer_2017">[httpshttp://www.facebookasbcnet.comorg/publications/journal/groupsvol/MilkTheFunk2017/992202820807932Pages/?comment_id=993485744012973 Conversation with professional brewer Anthony Accardi ASBCJ-2017-3861-01.aspx Sour Brewing: Impact of Lactobacillus amylovorus FST2.11 on MTFTechnological and Quality Attributes of Acid Beers. Lorenzo C. Peyer, Martin Zarnkow, Fritz Jacob, David P. Schutter, Elke K. Arendt. 2017.]</ref>.

==See Also= Unwanted Microbes ====Additional Articles on MTF Wiki===* [[Wort Souring]]Due to the mixed culture typically added to a sour mash from the addition of unused grains of malt after the mashing process, unwanted microbes such as ''Clostridium sp''. can take old in a sour mash and produce off flavors such as * [[Butyric Acid|Butyric acid]] and possibly * [[Lactobacillus]]* [[Isovaleric Acid|Isovaleric acidAlternative Bacteria Sources]].

Should the ===External Resources===* [http://www.fivebladesbrewing.com/presentations/berliner-and-beyond-sour-mashing-and-its-applications/ Berliner and Beyond: Sour Mashing and Its Applications. Derek Springer's NHC 2015 audio and slides.]* [http://www.fivebladesbrewing.com/year-sour -mash display prominent character / "Year of these spoilage organisms, such as rancid aroma or moldy patches, it may be advisable to not use the Sour Mash" by Derek Springer. This series of articles were written for his NHC 2015 presentation.]* [http://homebrewingfun.blogspot.com/2010/10/sour -mash-how-to.html "Sour Mash How-To", by Adam Kielich (Brain Sparging on Brewing blog). If the ]* [http://byo.com/kegging/item/1691-sour-mashing-techniques "Sour Mashing: Techniques", BYO, by Dave Green. October 2008.]* [https://byo.com/videos/item/889-how-to-make-a-sour -mash is not acidic enough it is possible for human pathogens -techniques "How to be present in the mashMake a Sour Mash: Techniques", and it may not be advisable to taste the mashBYO, especially if noticeable spoilage aroma is detectedSeptember 2000. ]* [[http://suigenerisbrewing.blogspot.com/2015/07/how-i-sour-mash-recipe.html "How I Sour Worting|Sour worting]Mash & a Recipe"; Sui Generis Blog (includes microbiology information).] is generally not as susceptible to these spoilage organisms.