Can you cool the wort too much?

I started my second batch today, with steeped grains and extract. I cooled the wort in the kettle down to 75deg in 20min in the sink with ice and water, and not completely thinking, added the extra 3 gallons of water to bring it up to ~5 gallons. The water had been cooled so when I checked the temp it was 56deg for the full 5gal.

I had rehydrated the yeast at 68deg and pitched it anyway, assuming that you cannot overcool yeast, just kill it with heat. Is this OK? Is there harm in the wort being too cool or of "shocking" the yeast?

I figure that once the wort warms up to room temp (aiming for 68deg in a 72deg room right now) it should be fine. Any thoughts?

you've made one more batch then me but....

aren't you supposed to pitch the yeast before you add the water?

No, you need to get the wort to 5 gallons before you pitch. Take your Hydrometer reading, aerate some, then Pitch. As far as the original question goes, you are probably right. It will just be a slow-starter. I usually pitch the yeast when the wort is around 75F, and let it ferment at the recommended temp for the yeast I'm using.

If you pitched at 56 degrees, then just let it warm up and it will be fine. The fermentation will start slower, but there shouldn't be any effects.

Thanks to all. I figured as much, but thought I'd check. It's comforting knowing there's a place for such noobie questions.

the temperature differential between the wort and the yeast will shock the yeast (you wouldn't like it if someone threw you into a 56F pool, would you?!), but will end up just fine. many breweries and brewers start ales fermenting at low temperatures and allow the wort temperature to rise slowly. this practice prevents fusel alcohol and ester production, resulting in a cleaner tasting beer.

Well, it was bubbling away after 15 hours (2-3bubbles/second), so I figure it was just fine and warmed up well. Now it's sitting at 66deg and still vigorous. I had read that there are less esters at lower temps. I guess I'll get to see!

I love this hobby, but this whole waiting thing is getting old. Thanks for the info.

The only cure for the waiting game, is to make more batches!

EvilTOJ said:

The only cure for the waiting game, is to make more batches!

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+++1 there!!

Do not want to wait? BREW MORE!!

Greenspey said:

I had rehydrated the yeast at 68deg and pitched it anyway, assuming that you cannot overcool yeast, just kill it with heat. Is this OK? Is there harm in the wort being too cool or of "shocking" the yeast?

Any thoughts?

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When rehydrating dry yeast you should have your water at the proper temperture. Higher or lower than recommended will stress out the cells.

http://www.bodensatz.com/staticpages/index.php?page=20020430195005429