Expert: Ed Westemeier - 10/15/2007

Question
QUESTION: I just started my first batch of pale ale and everything went as expected accepted I realized after I rehydrated my yeast that I didn't sanitize the yeast container enough (the solution was 1/5 of the strength it needed to be).  I thought it might not be a big deal since it seemed to hydrate well.  I pitched it and let it sit but I was worried that my place was too warm since the thermometer on the fermenter said 78 F so I started to leave a window open.  The first day and a half there was a lot of activity from the airlock.  Unfortunately I left the window open on the second night (I tried to close it then so it wouldn't get too cold but forgot) and the thermometer on the fermenter said it was 62 F but there was no activity from the airlock anymore.  I closed the window and moved the fermenter to a warmer room and shook the fermenter to resuspend the yeast and it seemed to bubble a bit more but nothing lasting.  Is the yeast dead or just dormant?  Should I pitch more yeast, leave it be, or start over?  Thanks.

ANSWER: It's possible that you "shocked" the yeast with the drastic chilling from the high 70s to the low 60s, and it went dormant on you. It's also possible that you just had a quick fermentation and it's all done. The only way to tell is by taking a hydrometer reading of the specific gravity.

Compare it with the measurement from the time you pitched the yeast (you did take a reading then, right?) and you'll know.

However, if we assume the worst (and if it's your first batch, that's a reasonable assumption ;-)), then the easy way out is to simply pitch some new yeast. If the fermentation takes off again, you're fine. If it doesn't, then you'll know it was already done.



---------- FOLLOW-UP ----------

QUESTION: Will the addition of more yeast affect the taste too much or will it just simply settle to the bottom?  Also, how much yeast should be pitched?  The same as the recipe or half?  Thanks.

Answer
Just pitch the same type and same amount of yeast, and there won't be any effect on the flavor. There is only so much sugar in the wort for the yeast to work on, and when it's done, it's done. You want to use at least the same amount, because if the original yeast was really knocked out by the temperature, then there has been plenty of time since then for off flavors to develop due to wild things in the air. They like the sugar, too, but they don't contribute good flavor like a good beer yeast.