Killed yeast in starter. Pitch new packet?

[DerekS]

Well had a great brew day, thoroughly sanitized everything, aerated well, and was only a 1.042 beer. Was expecting the fermentation to take off after having made a starter (Wyeast1007 German Ale) but absolutely nothing was happening by the 24 hour mark, so I shook up my fermenting bucket to try and get something going.

Well I was away for work and had my wife make my starter and when I was trying to find out what was going on we realized that she did not cool the starter wort in an ice bath but just left it sitting for 30 minutes to cool on its own.

So realizing the unfortunate circumstance of her killing the yeast in that hot bath I was planning on buying another yeast pack today to pitch in; but yesterday around the 40 hour mark to my surprise the airlock was going off really good, I guess somehow a few lucky ones survived!

So now for my question; do I still pitch in another pack to help out or do I wait and see if this thing attenuates, and if not all the way only then pitch again?

 

[Bearclaw215]

If fermentation has visibly started there's enough yeast in there another packet most likely isn't going to be of much help. Chances are there was plenty in there to begin with and there was just some lag. Just let it do its thing.

 

[DerekS]

If fermentation has visibly started there's enough yeast in there another packet most likely isn't going to be of much help. Chances are there was plenty in there to begin with and there was just some lag. Just let it do its thing.

So how do you suppose the yeast survived the hot wort, at what temperature will they die? Was 30 minutes enough time to cool and maybe the yeast were just used to hot fermentation temperatures and were slow to want to work in the 70 degree wort?

 

[Bearclaw215]

~140F kills, ~120F injures yeast and rehydration is done at ~90, so the little guys are quite resilient. I can't guess what temp your starter might have been at but it obviously wasn't enough to kill them all off and they reproduced in the starter. The lag time can be from a few things like underpitching, 10F+ starter/wort temp difference shocking the yeast or a few other things. Trust me you yeast is happier in 70F wort than what it was in, each yeast has its fermentation range where its at its best and its good to stay around that or you risk stressing it. I wouldn't worry too much just take care not to scald your poor yeast again

 

[CraigKing]

Important lesson learned here - don't let your wife/gf brew your beer.

 

[DerekS]

~140F kills, ~120F injures yeast and rehydration is done at ~90, so the little guys are quite resilient. I can't guess what temp your starter might have been at but it obviously wasn't enough to kill them all off and they reproduced in the starter. The lag time can be from a few things like underpitching, 10F+ starter/wort temp difference shocking the yeast or a few other things. Trust me you yeast is happier in 70F wort than what it was in, each yeast has its fermentation range where its at its best and its good to stay around that or you risk stressing it. I wouldn't worry too much just take care not to scald your poor yeast again

Lol yeah will do. Next time I'll have to make a checklist sheet for her if I am away again. Thanks, I appreciate all the help!

 

[yogensha]

Important lesson learned here - don't let your wife/gf brew your beer.

Or make sure your starter is done before you pitch it. It takes seconds to pour a little taste.