Re-boiling an infected beer

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Gear101

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What if a home brewer got an infection and put the wart/beer back into a kettle and boiled it again. The brewer would boil it at 220 for 10-15 mins, hoping to kill off all the contaminates and the yeast would properly get killed off too. Then re-set it back into the fermenter and pitch new yeast, then continuing the process from there. Would that produces any off favors and other undesirable taste things or reduce the ABV?
 
I would try pasteurizing it by heating to 170F and holding it at that temp for 10 minutes or so. That should kill everything. Why does the brewer in question believe there is an infection in there? If it has progressed far enough to be noticable in smell or taste the prognosis is not as good.
 
Gear101 said:
What if a home brewer got an infection and put the wart/beer back into a kettle and boiled it again. The brewer would boil it at 220 for 10-15 mins, hoping to kill off all the contaminates and the yeast would properly get killed off too. Then re-set it back into the fermenter and pitch new yeast, then continuing the process from there. Would that produces any off favors and other undesirable taste things or reduce the ABV?

It depends on how far along the beer was. If it had an OG of 1.054 and is now at 1.052 then the alcohol and body wouldn't be affected much. But if its now at 1.030 then you're going to end up with a very different beer than planned if you boil.

The old yeast cells would actually act as nutrients for the new yeast.

As far as off flavors go, that depends on how much if them the infection produced before you boiled it again. Some might be volatile and boil off while someone would likely stay. I vote you try it if your beer isn't too far along and then taste the wort afterwards. If it tastes terrible then you're out of luck. If it tastes ok then go ahead and pitch new yeast.
 
I don't know what altitude you are at, but boiling at 220 might be difficult. All of the alcohol would be gone if you boiled at the usual 212, as the boiling point of alcohol is 172. Bittering would go down and much of the hop aromas would boil out.
 
Yes it would stop the infection but it may not taste any different. If the beer soured boiling it won't change anything except that it wouldn't get any worse. You would boil off the alcohol as well. This is assuming of course that your beer is at or near FG. I don't know how you would know that you even have an infection at the very beginning of fermentation.
 
An infection causes off flavors that don't require the infection to still be alive. If notice you have an infection, I think the chances are pretty high that you've already got off flavors in the beer from that infection that won't be affected by boiling and will remain in the beer.

That said, I've never tried this. You never know unless you try.
 

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