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Spontaneous Fermentation

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==Defining ''Spontaneous Fermentation''==
In the most romanticized view of spontaneous fermentation, the microbes which inoculate the wort in the coolship are sourced exclusively from the ambient environment outside the brewery. Scientific publications have suggested that in the case of some producers, these microbes may be resident in the brewhouse <ref name="Bokulic et al., 2012">[http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0035507/ Bokulich et al, 2012]</ref>. This is supported by the reluctance of lambic brewers to alter their facilities (remodeling, moving, painting, etc.) and the spraying of lambic on the walls of new buildings <ref>[https://www.facebook.com/permalink.php?story_fbid=888263374558973&id=110627652322553/ Cantillon Facebook post 5-February-2015]</ref> <ref>[http://www.latisimports.com/assets/uploads/2009/11/MBA_Boon_October_Article.pdf/ Modern Brewery Age Weekly 23-October-2009 Article by Peter Reid with Frank Boon, accessed 7-May-2015]</ref>. The microbes responsible for spontaneous fermentation may also be derived from the oak barrels and/or foedres which are often used to hold the fermenting beer, especially if the barrels/foudres have not been thoroughly cleaned <ref name="Spitaels et al., 2015">[http://www.sciencedirect.com/science/article/pii/S074000201500012X/ Spitaels et al., 2015]</ref>. Many Belgian lambic producers thoroughly clean their barrels using hot water/steam, mechanical agitation (such as is seen at [[Cantillon]]), and/or burning sulfur <ref> Conversation between Dave Janssen and Steven Sonck of [[De Cam]], winter 2014</ref>; however even the most rigorous cleaning likely does not fully sterilize the barrels. In the case of lambic brewers the microbes resident in barrels are spontaneous in origin, having been derived from years to decades of use in the brewery without any exposure to pitched cultures and the barrels may serve as a concentrating mechanism for the desired cultures. The role of barrels as an inoculating vessel is unclear as some producers report achieving excellent results in barrels new to the brewery and which are microbially clean (<ref name="Spontaneous Sour Hour" /> (~35 min in).
A spontaneous fermentation may also be achieved by inoculating small amounts of wort and growing up the spontaneously inoculated microbes to check for suitability. This is common in homebrew production <ref> [http://www.themadfermentationist.com/2011/04/ambient-spontaneous-yeast-starters.html The Mad Fermentationist Spontaneous Starters, accessed 7-May-2015]</ref> and allows for screening of the microbes to remove wild cultures with aggressive off flavors and/or mold. This is not unlike the potential of used oak barrels, where well performing barrels may be kept to inoculate subsequent batches while poorly performing barrels may be discarded and removed from the brewery. As different microbes survive and thrive in different environments, barrels or pre-screened and grown starters will probably not provide a complete profile of the microbes present in traditional spontaneous fermentation beers. However a combination of a coolship to inoculate the wort with ambient/brewhouse resident microbes combined with a form of pre-screening such as barrel re-use and/or spontaneous starters may provide the full microbiota present in traditional spontaneously fermented products. For the purposes of this page, beers receiving additions of isolated cultures or bottle dregs are not treated as spontaneous and are discussed under [[Mixed Fermentation|mixed-culture fermentation]].
Traditional spontaneous brewers use high hopping rates of aged hops in a long boil. The high hopping rates help to regulate bacterial activity and select for the desired bacteria (''[[Pediococcus]]'' rather than ''[[Lactobacillus]]''. Aging of the hops lowers the flavor/aroma impact the hops provide and also lowers the bitterness. The aged ops still do provide some bitterness as both oxidized alpha acids and oxidized beta acids can contribute to perceived bitterness and measured IBUs <ref name="OSU talk at CBC 2015"> Understanding How to Control Flavor and Aroma Consistency in Dry Hopped Beer. Dan Vollmer, Dan Sharp, Dr. Tom Shellhammer (Oregon State University). Oral presentation at the 2015 Craft Brewers Conference</ref>. Cantillon uses hops that are on average 2-3 years old at hopping rate of 250-300g/100 L (3.34-4.0 oz/gal) <ref name="Spontaneous Sour Hour">[http://www.thebrewingnetwork.com/membersarchive/sourhour2015_05_wildfriendship.mp3 The Sour Hour Episode 11 with Rob Tod and Jason Perkins from Allagash, Jean Van Roy from Cantillon, and Vinnie Cilurzo from Russian River]</ref>(~49 minutes in). Other producers use higher hopping rates . The use of significantly lower hopping rates may result in less bacterial inhibition and lead to different types of bacteria present. Some lambic producers are experimenting with the use of fresh dried hops in addition to or instead of aged hops <ref> [http://www.cantillon.be/br/3_108 Cantillon Iris]</ref> <ref>[https://www.facebook.com/permalink.php?story_fbid=1004839069568069&id=110627652322553 Cantillon Facebook Page post 22-Sept-2015]</ref> <ref>Conversation between Dave Janssen and Jean van Roy of Cantillon, 17-Sept-2015</ref>
A [[coolship]] is an open vessel used to cool wort by exposure to ambient air which traditional spontaneous fermentation brewers use to both cool their wort and to inoculate the wort with ambient microbes during the open overnight cooling. Traditionally, a coolship is a broad, open-top, flat vessel in which wort cools overnight. The high surface to volume ratio allows for more efficient cooling, which is important at commercial production scales. In addition this broad, shallow design maximizes the area of wort available for inoculation with ambient microbes. On a homebrew scale, where typical batch sizes cool more quickly, a wide shallow pan is not necessary to achieve appropriate cooling overnight given sufficiently low nighttime outdoor temperatures and the use of a wide shallow pan might result in cooling at a much more rapid rate than seen in traditional commercial production. Boil kettles and similarly shaped vessels are sufficient for overnight cooling for most homebrew batch sizes and may provide a rate of cooling more similar to that provided by coolships in commercial production sized batches <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1068826853145528/ Facebook post by James Howat] </ref>. However the aspect ratios of these sorts of vessels may limit the inoculation of the wort by ambient microbes due to the lower surface area for a given volume compared to traditional coolships. Cantillon targets a cooled wort temp of 18-20 C (64.4-68 F) after the overnight cooling (<ref name="Spontaneous Sour Hour" /> (~50 min in). Traditional producers only carry out spontaneous fermentation between fall and spring when nighttime temperatures are sufficiently low (max nighttime minimum of about 8°C <ref>Conversation between Dave Janssen and Armand Debelder of [[3 Fonteinen]], July 2011</ref>) to appropriately cool the wort overnight. The ambient microbial balance may also be more favorable during this time of year (--some sources say more bacteria in summer--), but inadequate cooling could result in similar results of enhanced acid production (similar to the effect of warm incubation in [[Sour Worting|sour worting]], see also Alternative applications of ''Spontaneous Fermentation'' below). Whatever the root of the different resulting beers based on time of season/ambient nighttime temperature, producers do report different times of year/temperatures exerting a strong influence on the final beer <ref name="Spontaneous Sour Hour">[http://www.thebrewingnetwork.com/membersarchive/sourhour2015_05_wildfriendship.mp3 The Sour Hour Episode 11 with Rob Tod and Jason Perkins from Allagash, Jean Van Roy from Cantillon, and Vinnie Cilurzo from Russian River]</ref>(~39 minutes in, ~54 minutes in).
Fermentation temps----------------- to do. <ref name="Spontaneous Sour Hour">[http://www.thebrewingnetwork.com/membersarchive/sourhour2015_05_wildfriendship.mp3 The Sour Hour Episode 11 with Rob Tod and Jason Perkins from Allagash, Jean Van Roy from Cantillon, and Vinnie Cilurzo from Russian River]</ref> (~1:14 in), Armand ref.
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