Re ferment beer after transferring to keg and force carbonating it

Question

Re ferment beer after transferring to keg and force carbonating it

Mark Veilleux

2016年1月22日 12:25

I brewed a 5 gallon batch of IPA beer, the OG was 1.067 and 2 weeks later it only dropped to 1036. A stuck fermentation I was told after I transferred it from my fast fermenter to two 3 gallon kegs. I forced carbonated both and tried the beer a few days later. Way to sweet for my taste. My question/idea is to use Co2 to prime the fermenter then transfer from the keg to fermenter via Co2, re pitch champagne yeast and hope to dry it out. Would their be enough oxygen in the beer for the yeast to do it's job? Would adding yeast nutrient to the beer help? Newbie questions I know... Thanks, Mark.

Topic fermenter stuck-fermentation homebrew

Category Mac

brewchez · Accepted Answer · 2016年1月22日 12:25

I have largely found the "miracle" of champagne yeast to be a myth. It hasn't worked well for me. The failings of pitching dried champagne yeast is primarily due to two things.

First, champagne yeast prefers to ferment the simpler sugars found in grape must. A stuck ferment in a malt based wort generally has a higher ration of complex sugars to the simple sugars. The beer yeast already fermented the easy stuff. Champagne yeast, therefore, will have a tough time with those sugars.

Second, a partially fermented wort has experienced a drop in pH and an increase in alcohol. Most any yeast, champagne or brewers, will have a tough time going from a dormant state (dried or liquid) to a fermentative state under those conditions.

I have seen that champagne yeast will get things moving again, but I have yet to see something ferment out with champagne yeast. It usually still will finish several points above where it total attenuation could have been.

A better approach is to get a 500ml to 1L starter going. Wait until it is very active visually and pitch that active starter in. Picking up a little oxygen at this point incidentally from pitching the starter won't hurt much.

You can do this with more of the same yeast already used, or chose a yeast with a higher alcohol tolerance than the one previously pitched. Before pitching the active starter I'd recommend warming the stalled beer up to 68F-70F if it isn't there already. (which is usually a better place to start to unstuck a ferment than pitching new yeast, IMO)

Evil Zymurgist · Accepted Answer · 2016年1月22日 02:12

Fortunately dry yeast has matured past the aerobic stage for dehydration and packaging.

You will be ok to transfer to a fermenter and try a repitch of dry yeast with out oxygen. This will limit cell reproduction but you shouldn't need a large colony to finish the fermentaion.

I would try a single pack of an ale yeast first, as champaign yeast will consume all fermentables and leave it very dry.

Also you need to identify what caused the stuck fermentation. Many things could cause this, but the worst case in your situation would be the mash temp was above 158° making a lot of a hard to ferment sugars.

Re ferment beer after transferring to keg and force carbonating it

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