High Gravity

[chefbri]

I accidentally added way too much LME to an English Bitters recipe. My concern is that the higher alcohol content will kill the yeast. I used a Wyeast London Ale III which has an alcohol tolerance of 10%. My original brix reading was around 23 (1.097 I think). I'm thinking that this will put the alcohol content at 14%. Should I be concerned? Should I just let it ferment out and check the gravity when airlock activity ends? If the final gravity is too high should I rack and pitch a yeast with a higher tolerance? Thanks.

 

[poptarts]

How much yeast did you pitch? And, 1.097 wont get you to 14% your probably looking at 10 - 11%

 

[morticaixavier]

and those alcohol tolerance numbers are just a ball park figure anyway. I've fermented the whitelabs version of that very yeast to over 12% with no problem.

 

[BradleyBrew]

Most likely the yeast will explode.... causing your beer to be ruined.

 

[MKBoitnott]

The yeast will probably get very drunk and make bad life decisions.

 

[BradleyBrew]

- drop out of school
- bud with multiple partners without protection
- use this exceptional amount of alcohol as a gateway to more hardcore drugs...
- etc.

 

[chefbri]

Got it. I pitched 1 smack pack. My problem was the brix to specific gravity conversion. I used onebeer.net's brix converter. I entered original brix and estimated final brix and it gave me the 14%. I know final gravity with a refractometer isn't very accurate. I found another converter that predicts my alcohol content at 9-11% (as you say). Thanks for the input.

 

[sweetcell]

making it to 10% abv or higher with only one pack of yeast will be a challenge. did you make a starter? did you aerate a lot? nutrients?

getting up above 10% isn't as simple as adding more fermentables. alcohol is toxic to yeast, so to get to high % you need to baby the beer - pitch A LOT of healthy yeast, give them a lot of O2, etc. without the coddling, the yeast is likely to give up before it gets you to 10%. http://www.mrmalty.com/calc/calc.html suggested pitching 3.4 packs of ultra-fresh yeast, or 4.2 packs of one-month-old yeast, or making a 3.35 liter starter with 2 packs of month-old yeast. so one pack, without a starter, would be a big under-pitch.

please let us know how this beer turns out!.

 

[sweetcell]

If the final gravity is too high should I rack and pitch a yeast with a higher tolerance? Thanks.

you may well need to pitch another yeast to finish the job, however you can't pitch it directly. you need to get it active by putting in a starter and let it get into munching mode in a non-alcoholic environment. let it get going for about 48 hours (or until it reaches maximum activity, AKA high krausen) then pitch that into the stuck beer.

but first let's see how far your first yeast pitch takes you.