13,592
edits
Changes
first pass at yeast acclimation instructions
When bottling or priming a keg at packaging time, the brewer should consider re-yeasting. In a long aged beer, especially an acidic beer, the ''Saccharomyces'' will mostly be dead already. This leaves ''Brettanomyces'' in charge of conditioning the beer. Although some lactic acid bacteria are capable of producing CO2, their contribution is probably negligible. It is also possible that homofermentative LAB will consume a portion of the sugar before the ''Brett'' has a chance to produce CO2. Re-yeasting is a very effective way to ensure proper CO2 levels in an aged sour beer. Another benefit of re-yeasting is that it tends to help avoid (or minimize) [[Tetrahydropyridine]] production.
Commercial producers and MTFers have had success re-yeasting with their mixed culture, wine yeast, and champagne yeast. The specific yeast you choose is up to you, and we recommend that you try a couple different yeasts out to find the one you prefer (MTFers have reported success with Lalvin EC-1118 Champagne, Red Star Premier Cuvée, Red Star Pasteur Blanc, Danstar CBC-1, Fermentis T-58, Scott Laboratories DV10 wine yeast, and fresh cultures of ''Brettanomyces'' <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1477763322251877/ Conversation on MTF regarding bottle conditioning yeast. 11/21/2016.]</ref>). When re-yeasting at bottling, it is not recommended to add new highly attenuative yeast to make sure that the bottling yeast you add cannot ferment additional carbohydrates remaining in the beer <ref name='Sour Hour episode 6'/> (~41 minutes in). Re-yeasting with a yeast that beer has already seen should eliminate the possibility of continued attenuation as long as the beer is already at final gravity. Brewers who are having difficulty carbonating sour beer or need to ensure that the beer will carbonate properly should grow their yeast first in a yeast starter that has yeast nutrients (Fermaid K + DAP, for example) and diluted 1:1 with the sour beer itself. This will acclimate the yeast to the harsh conditions of the sour beer, and has shown to be more effective for ensuring bottle carbonation <ref>[http://www.sciencedirect.com/science/article/pii/S0740002016301605 Terminal acidic shock inhibits sour beer bottle conditioning by Saccharomyces cerevisiae. Cody M. Rogers, Devon Veatch, Adam Covey, Caleb Staton, Matthew L. Bochman. 2016.]</ref>. See [[Saccharomyces#Fermentation_Under_Low_pH_Conditions|Fermenting in low pH conditions]] for more informationon what can cause this, and the ''acclimation starter'' methods below.
The yeast required for carbonation is very little. A good rule of thumb to use is to use 10% of the yeast that you would normally use for a primary fermentation (approximately 1 million cells per mL). For example, for dried yeast use ~2 grams of yeast for 5 gallons of beer <ref name="priming_calc">[http://jeffreycrane.blogspot.com/2015/06/blending-calculator-ph-abv-and.html Blending Calculator - pH, ABV and Carbonation. Jeff Crane. Blending Calculator - pH, ABV and Carbonation. Bikes, Beer, & Adventures Blog. June 12, 2015.]</ref>. Rehydrating the yeast is recommended. See [http://jeffreycrane.blogspot.com/2015/06/blending-calculator-ph-abv-and.html Jeff Crane's "Blending Calculator" (extension of Michael Tonsmeire's "Blending Calculator")] for a re-yeasting and priming calculator.
* [http://www.lewybrewing.com/2012/12/wine-yeast-in-beer-experiment.html?m=1 Chris Lewis's write up on wine yeast character/Killer Factor on Lewy Brewing Blog.]
* [http://www.babblebelt.com/newboard/thread.html?tid=1108752780&th=1275037001 Shea Comfort notes on wine yeast on the BBB.]
<blockquote style="background-color: lightgrey; border: solid thin grey; padding:10px;">
'''Escarpment Labs Acclimation Protocol'''
The following acclimation protocol has been adapted for sour beer from Richard Preiss's instructions on how escarpment Labs acclimatizes wine yeast: <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1363395580355319/?comment_id=1364119323616278&reply_comment_id=1364521000242777&comment_tracking=%7B%22tn%22%3A%22R9%22%7D Wine yeast acclimation protocol for Escarpment Labs by Richard Preiss. 08/01/2016.]</ref>
# Take a "pinch" of rehydrated dried yeast, and pitch 150,000 cells/mL into 100 mL of '''YPD + Go-Ferm Media'''. Grow for ~24 hours at 30°C with shaking.
# Transfer the starter into 100 mL of '''Adaption Media 1'''. Grow for ~24 hours at 30°C without shaking.
# Transfer the starter into '''Adaption Media 2''' (whatever volume is needed for batch size). Grow for ~24 hours at 30°C without shaking.
# Pitch ~1 million cells into each bottle, along with priming sugar.
Definitions:
;YPD + Go-Ferm Media (autoclaved):
: 0.02375 g/L Go-Ferm
: 10 g/L yeast extract
: 20 g/L peptone
: 20 g/L dextrose
;Adaption Media 1 (filter-sterilized)
: 10% base sour beer
: 20 g/L sucrose
: 0.02375 g/L Go-Ferm
;Adaption Media 2 (filter-sterilized)
: 70% base sour beer
: 20 g/L sucrose
: 0.2 g/L Fermaid
</blockquote>
<blockquote style="background-color: lightgrey; border: solid thin grey; padding:10px;">
'''Homebrew/Low Tech Acclimation Method'''
This method was adapted from the Escarpment Labs and the Rogers et al. methods using non-laboratory processes and ingredients.
For ~20 liters (or around 5-6 gallons) of sour beer:
# Measure 1-2 grams of dried yeast, and re-hydrate in a little bit of warm water.
# Measure 50 mL of the sour beer that is going to be carbonated, and combine it with 100 mL of apple juice and a pinch of yeast nutrient in a saucepan.
# Heat pasteurize the sour beer, apple juice, and yeast nutrient mixture on the stove at 140°F for 10 minutes.
# Cool the sour beer and apple juice mixture to around 70-85°F. Pitch into an Erlenmeyer flask, along with the re-hydrated wine yeast.
# Grow for ~24 hours without shaking.
# Measure 200 mL of sour beer that is going to be carbonated, and combine with 200 mL of apple juice and a pinch of yeast nutrient in a saucepan.
# Heat pasteurize the sour beer, apple juice, and yeast nutrient mixture on the stove at 140°F for 10 minutes.
# Cool the sour beer and apple juice mixture to around 70-85°F. Top up the Erlenmeyer flask with the yeast starter in it with this fresh mixture.
# Grow for ~24 hours without shaking.
# Continue to step up the starter as needed for larger batches.
# Add ~200 mL of the starter per 20 liters of beer (shake the starter before adding into the beer).
</blockquote>
===Priming===