Changes

Many commercial sour beers are bottle conditioned with fresh wine or Champagne yeast. If this yeast is still viable, it is possible that it could contribute to the fermentation profile under the right conditions, however in most cases Champagne/wine yeast from bottle dregs usually won't have a significant impact. 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 living ''Brettanomyces'' since ''Brettanomyces'' 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. When dregs containing viable Champagne/wine yeast are added to a starter, then that yeast will often grow into a healthier population, which could then have a large flavor impact from the Champagne/wine yeast if the starter is pitched into primary. If other flavor contributions by from bottling yeast are a concern (esters, thiols, etc.), then cooling the beer and leaving the sediment behind before building a starter may help to alleviate the problem, however, at least some the wine/champagne yeast will probably still be in suspension in the beer. Dregs or a starter from 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 the 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 bottled beer has aged (for 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>.