Re-hydrating Yeast

[Nicknack]

Well, that would definitely include me "mostly for beginners". However, I didn't want to chance not having enough active yeast which is I why I decided to go against the directions on that piece.

 

[kombat]

I agree - I think it's to prevent inexperienced brewers from accidentally killing their yeast (by rehydrating it in too-hot water) or contaminating their batch (through poor sanitation during the delicate rehydration procedure).

 

[Nicknack]

That makes sense. I'm glad I didn't listen to their advice.

 

[eadavis80]

Yeah, I'd say the kit's instructions are written as a way to minimize mistakes so the product's customers will seem happy with said product. Can you ferment just fine without rehydrating? Absolutely? Is there a chance rehydrating will be done incorrectly, thus the beginning brewer will blame the kit? Absolutely. To be fair, in my first few kits I didn't rehydrate and I'm not sure there was a difference. I do now as it's "best practice" but it would be a good experiment - to split a batch between rehydrated and pitched dry yeast and see if there was a difference.

 

[kombat]

it would be a good experiment - to split a batch between rehydrated and pitched dry yeast and see if there was a difference.

Someone should totally do that.

 

[eadavis80]

I'm 99.9% sure I read that experiment before on here

 

[Nicknack]

Someone should totally do that.

Good read, thanks sharing the link. The results of the experiment seem to be fairly consistent with what I've been reading in posts from people on this board. That is, on brews under .0160, you can probably get away without re-hydrating the yeast. However, with higher gravity brews (such as 1.070 like I just brewed), you will probably start seeing a difference.

It would be interesting to do this experiment at 1.060, 1.070 and 1.080 to see if the changes increase as there is an increase in gravity. Perhaps this has been done - if so, I would love to learn about it!

 

[slym2none]

Did you mean 1.060, 1.070, & 1.080???

 

[Nicknack]

Did you mean 1.060, 1.070, & 1.080???

Yes, thanks. I just edited it to avoid confusion.

 

[BigFloyd]

Don't you risk shocking your yeast pitching it around 85-90 degrees if your wort is chilled to about 70 degrees? The instructions that I've been following recommends getting the yeast within 5 degrees of the wort. After looking more at other directions for re-hydrating yeast, I've seen within 10 degrees as well.

85-90*F is the original temp of the water that the packet of yeast is added to, not the temp of the slurry at pitching time .

I should have mentioned that, after giving the yeast the proper amount of time to rehydrate (as per the yeast instructions) I'll "attemperate" the slurry by adding a small amount of the cooled wort (I pitch ales around 60-62*F), stir and wait a few minutes. By the second or third addition of the cooler wort, the slurry is within 10*F of the wort and ready to pitch.

 

[kombat]

I rehydrate with water at an initial temperature of 85° F. During the 20 minutes of "resting," and 30 minutes of stirring, it cools down to match the ambient air temperature (around 70° F), which is well within 10° of the wort it's being pitched into (62 - 68° F).

For lagers, I build a big starter (I'm making one tonight, actually, 5 quarts), put it on the stir plate for 2 days, then cold crash it. On brew day, once I start the boil, I take it out of the fridge and let it gently warm up a little while I finish brewing. By the time the wort is ready and chilled down to 50° F (easily achievable with my wort chiller and tap water at this time of year), the yeast has warmed up slightly (but not fully to room temperature). I decant the spent wort, swirl up the slurry, and pitch it; again, within 10° of the wort temperature.