Looking to stop fermentation

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smarek82

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Just did my first Lager and it has been in primary for about 25 days and still has not reached my anticipated FG(1.011). The problem is I got a little crazy with the boil and ended up boiling too much off. The anticipated OG was supposed to be 1.046, but ended up 1.056. Right now after a gravity reading it is at 1.016 and I think it tastes and looks great. No trace of diacetyl, clear, and just slightly yeasty.

I have potassium metabisulfate from when my dad used to make wine. I guess my question would be....Can I use this to stop fermentation? If so, How much?

Also, is it a good idea to do this? I just don't want the beer to drop down to the anticipated FG of 1.011. I think it will be too alcohol forward.

Thanks.
 
Well, no. I wouldn't recommend adding sulfite to your beer.

Beer and wine yeast strains are pretty tolerant of sulfites, so it doesn't really kill yeast anyway, just sort of stuns them in high doses. Smaller doses, so that the whole batch doesn't taste like sulfur, don't kill yeast. Also, you want to let the beer ferment until it's done. It might not get to 1.011 anyway. When the SG is the same over a period of time, it's done.
After 25 days in primary, you may not go any lower. I'd be surprised if it dropped any more.

If you did manage to kill the yeast, how are you going to condition? Are you planning on bottle carbonating?
 
+1 to the above. Your "anticipated" FG is based on a much lower OG, so your new "anticipated" FG is now much higher also. After 25 days, I'd also guess that it's about as low as it's going to go.
 
+2. Just because a recipe has listed a F.G. does not mean that the yeasties will abide and reach that no matter if other variables change. Higher OG usually translates to higher FG (as attenuation works in percentage of sugars). Plus, if your higher OG was due to high boil off rate, as opposed to say, better efficiency, you probably experienced greater melanoidin formation in the boil, thus driving up your expected FG as well. That's another thing to keep in mind if/when you try to replicate this beer later on in terms of getting the same flavor.
 
Thanks for the great information. I used wyeast american lager so the attenuation i believe was 73%-77% and taking law of averages it would attenuate to 75% giving me a FG of no less than 1.014. I do plan on bottle conditioning so i guess killing the yeast would be a bonehead idea.

thanks!
 
Those attenuation numbers are really only good for comparing between yeasts. For instance, 1056 also has 73-77% listed. I, and many others easily get it to hit 80% or more for certain beers.
 

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