Hydrating Yeast Question

[bennyd]

Ok....I finally got all of my equipment yesterday and have had a great time looking over it, playing with it, and reading up on directions. I looked through my first two recipe kits and I have a question on hydrating the dried yeast.

If you have to cool the wort to below 75 degrees before pitching, then why would you rehydrate yeast in water that is 90-100 degrees? I'm not doubting the directions at all as I've read that in multiple places. I'm just curious as to the difference.

Why would the warmer temps kill the yeast in the wort, but work fine to rehydrate them?

 

[ajf]

The warmer temperatures aren't enough to kill the yeast, but fermenting at warm temperatures can produce some rather unpleasant flavors. When you hydrate the yeast, it isn't fermenting, it's just being woken up and made ready to ferment at proper temperatures.

-a.

 

[bennyd]

Thanks for the quick reply, ajf. That makes sense. Just wanted to make sure I didn't do anything that would make me come on here and start a "did I kill my yeast," thread.

 

[northernlad]

The temperature of the yeast will drop while it is rehydrating putting it closer to your wort temp.

 

[budbo]

I have personally never seen the need to rehydrate, just dump it straight from the pack and it will be fine.

 

[MurderMittenBrewing]

I have personally never seen the need to rehydrate, just dump it straight from the pack and it will be fine.

I've done both - rehydrating and direct pitching. I noticed that fermentation starts much more quickly when I rehydrate. Dry yeast is packed with yeast nutrient, so I suppose rehydrating gives the yeast a head start.

 

[beerthirty]

I've done both also, and haven't noticed much difference. But when using dry yeast I usually drop 2 packets per bucket to speed things along.