Changes

In the traditional or long ferment method, the selective availability of carbohydrates to particular microbes allows the activity of those microbes to occur in a natural succession. As the microbes with better competitive ability run out of metabolic resources microbial groups with lower competitive advantage, but wider access to metabolic resources, begin their primary activity. In the short fermentation method, the brewer controls the phases of microbial activity. This allows the brewer to introduce the microbes with the lowest competitive ability to the wort first, allowing them to act on the simplest sugars and establishing their population in the absence of better competing microbes. The order of primary microbial activity in the short fermentation method is, therefore, often the opposite of the order typically observed in the long fermentation method. Further, this approach allows the brewer to maintain temperature profiles that are optimal for each microbial phase. Since the phases are controlled by the brewer, there isn't a need for the longer chain sugars that are generally included in the wort designed for long fermentation because the microbes with lower competitive ability have already been established in the beer by the time the better competing microbes are introduced. For this reason, the beer can fully attenuate within 3-4 weeks of it's final inoculation in many cases. It is important to note however that care should be taken in the decision to bottle these beers in such a short time frame (See bottling section below). Once the beer has reached full attenuation the beer can be packaged, in some cases this can be only 6-8 weeks from brew day(see [[Mixed_Fermentation#Fermentation_in_Less_Than_3_Months|Mixed Fermentation In Less than 3 Months]]). A number of biochemical reactions that effect flavor and aroma may still take place over a period of weeks, to months or even years, however, most of these reactions do not involve the evolution production of carbon dioxide so these reactions may take place in the bottle.

The grain bill for a short fermentation sour can be based on nearly any style. In contrast to the low fermentability wort used in the long ferment method, the wort used in the short fermentation method is generally designed to be highly fermentable. This is because the order and timing of microbial inoculation, rather than natural succession of the microbial community, is used to control acidity and fermentation characters. A few modifications to grain bills can be made to increase the fermentability of the wort and accomplish the full attenuation of the wort in a relatively short period of time. These modifications include lowering or removing crystal malts from the recipe and mashing for 90-120 minutes at 149F149°F/65°C. Extract brewers can steep 2-3 lbs. of crushed, malted 6-row or 2-row base pale malt at 149F in their kettle with their extract in order to increase the fermentability of their wort.

# Produce a low or no hopped wort (see the [[Mixed_Fermentation#Standard_Method|Standard Method]] above).# After boiling the wort, cool it to 11090-120°F (4332.3-48.9°C), and run it into the fermenter. The exact temperature depends on the culture being used (see the [[Lactobacillus#Culture_Charts|''Lactobacillus'' page for recommended temperatures).# Pitch a pure culture of ''[[Lactobacillus]]'', and if possible hold the temperature between 11090-120°F (4332.3-48.9°C) for 2-4 days (see the [[Sour_Worting#Souring_in_the_Primary_Fermenter|Souring in the Primary Fermenter]] page for more details).# After 21-4 3 days, or after the desired pH is achieved (generally between a pH of 3.0-3.7), cool the wort to 65-70°F (18.3-21.1°C), oxygenate the wort, and pitch a starter of ''[[Saccharomyces]]''.

# Add one or more cultures of ''[[Brettanomyces]]''. Optionally, also pitch a culture of ''[[Pediococcus]]'' and/or bottle dregs from commercial sours (see [[Commercial_Sour_Beer_Inoculation|Commercial Sour Beer Inoculation]] for more details on using commercial bottle dregs). For more ''funky'' Brett flavors, do not make a starter for the Brett. '''(Editor's note: new information suggests that the pitching rate for ''Brettanomyces'' in a mixed fermentation probably does not impact flavor. See [[Brettanomyces secondary fermentation experiment]] for more details).''' Also optionally, these additional microbes can be co-pitched along with the [[Saccharomyces]] during step 5.

Some brewers have been experimenting with mixed fermentations that can finish within 3 months. This approach to mixed fermentations takes some knowledge of the cultures being used and is considered to be an advanced topic. In general, use cultures that don't produce a lot of off-flavors early on in fermentation. For example, Omega Yeast Lab's ''Lactobacillus'' blend (OYL-605) and The Yeast Bay's Lorchristi ''Brettanomyces'' blends are good choices, for example. '''Warning: if mixed fermentation beers are bottled too early, they can result in bottle bombs or gushing bottles.''' Gareth Young offers his advise to brewers wanting to try mixed fermentations that finish within 3 months <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1262504037111141/?comment_id=1262518747109670&comment_tracking=%7B%22tn%22%3A%22R9%22%7D Conversation with Gareth Young on MTF regarding fast mixed fermentations. 03/24/2016.]</ref>: