Changes

Many commercial sour beers are bottle conditioned with fresh wine or champagne yeast. If this yeast is still viable, it may is possible that it could contribute to the fermentation profileunder the right conditions. For example [[Saccharomyces#Killer_Wine_Yeast|killer wine strains]] can kill ale or lager yeast, and potentially lead to autolysis off-flavors, although reports of autolysis in aged sour beer are next to none, and many believe that autolysis is not a concern in beers containing live ''Brettanomyces'' since ''Brettanomyces'' could potentially can consume the compounds that are released during autolysis <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1779575335404006/?comment_id=1782868198408053&reply_comment_id=1783095121718694&comment_tracking=%7B%22tn%22%3A%22R%22%7D DeWayne Schaaf on autolysis flavors. Milk The Funk Facebook group. 08/07/2017.]</ref>. Champagne/wine yeast could produce flavor compounds such as esters and thiols if it is introduced into wort during primary fermentation. If other flavor contributions by bottling yeast are a concern (esters, thiols, etc.), cooling the beer and leaving the sediment behind may help to alleviate the problem, however, at least some the wine/champagne yeast will probably still be in suspension in the beer. The Dregs containing champagne/wine yeast could be added after primary fermentation, which would eliminate any potential for the Champagne/wine yeast having a significant impact on flavor as far as producing esters from fermentation. Additionally, the long term survival of many wine strains of ''Saccharomyces'' yeast is usually limited in a low pH sour beer, so if the beer has aged (6+ months is an example estimate) then the chances of viable champagne yeast being in the bottle are low <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1268830686478476/?comment_id=1269605776400967&reply_comment_id=1270016239693254&comment_tracking=%7B%22tn%22%3A%22R%22%7D Conversation with Richard Preiss on MTF. 03/28/2016.]</ref>.  Many brewers have had success using bottle dregs that were conditioned with killer strains of champagne or wine yeast, and many consider it to be not a big concern due to the reasons previously mentioned.  See the [[Packaging#Re-yeasting|Packaging and Re-yeasting]] page for more details on killer wine yeast strains. If the brewer wants to guarantee that only ''Brettanomyces'' and/or bacteria are cultured, then they must use isolation techniques to do so <ref>[http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602008000200007 Occurrence of killer yeast strains in industrial and clinical yeast isolates. MARCELO E BAEZA*, MARIO A SANHUEZA and VÍCTOR H CIFUENTES. 2008.]</ref>.