Dry Yeast-To Rehydrate or Not to Rehydrate.

[11amas]

I believe JZ said something like "sure, don't rehydrate if you like the idea of killing off half of the yeast". If I buy a sachet full of yeast and I murder a large portion of them I feel like I am missing out. Really, if you look at the yeast mfgr. instructions for pro.s, they say rehydrate. They tell homebrewers to sprinkle so they can make it easier; maybe they pack in more cells than you need to pitch. On the other hand, maybe your yeast is already half dead from storage and time, now you sprinkle, kill off even more, and you have underpitched.
Rehydration does not take long, I microwave a 1 pint pyrex, set it in cool water with foil covering it (the foil gets a starsan spray and covers the steaming water at the end of the boil). The pyrex is about body temperature in less than an hour if I swap the water out a few times.

[whywhyzee]

Thanks for the perspectives. So if I rehydrate at 95 degrees, wait for :30 minutes, but pitch a bit too warm into 68 degree wort, I'm curious if this is worse than just sprinkling the dry yeast into raw wort. According to the Fermentis literature, they appear to be pretty indifferent whether you rehydrate or sprinkle. I found a pretty interesting article at:

http://koehlerbeer.com/2008/06/07/rehyd ... yton-cone/

It pretty strongly makes the case for rehydrating. I will say I like the convenience of the time savings and low infection risk of sprinkling however don't know if that is worth 60% viability.

[11amas]

Not 60% viability, 40% viability...6 of every 10 cells dies. You also don't know how long the dry yeast was stored above fridge temps so expect some initial death from the expected amount of cells. The moral for me is to either buy twice as much and let it die when you fail to rehydrate or rehydrate and do it properly (clean, right temp, right water...it isn't that tough).

More supporting evidence: http://www.danstaryeast.com/frequently-asked-questions

If you are of the opinion that you should sprinkle...do you store your hops at room temp and just take the loss of alpha for convenience? Do you do "no sparge" and just buy more grain accepting low extraction? Do you leave a few gallons in your mash tun and kettle instead of tipping because it doesn't cost much to waste a bunch of wort? If no, why are you suffering such losses in yeast? I guess it is pretty cheap but then make sure you pitch the proper amount I guess. I don't like slaughtering my workers and giving them a shitty start I guess. Remember, we make sugar water, not beer, yeast does that and we don't have much we can do after pitching besides patience and temp control to make better beer. I guess handling but it is already beer then.

Maybe I am crazy, what do you all think?

[Old_Skool]

""So if I rehydrate at 95 degrees, wait for :30 minutes""

Be careful as I believe yeasts like Fermentis S-04 rehydrate at 78-84 deg. Look at the package - visit the manufactures web site -- take your time - do it right.

As a former sprinkle and go guy I can vouch that PROPER rehydrating of dry yeast leads to much more rousing fermentations. Pitch as soon as possible - but keep the yeast mix and the woort with in 10deg or less of each other. Pitch the mixture and have a sanitized big spoon ready so you can give the wort and yeast a good mixing. Then seal it up and add air-lock.

[Old_Skool]

Not 60% viability, 40% viability...6 of every 10 cells dies. You also don't know how long the dry yeast was stored above fridge temps so expect some initial death from the expected amount of cells ..... Blah blah

Maybe I am crazy, what do you all think?

We all think you are bat-shit crazy -- unfortunetly I was voted the one to tell you this. Please don't shoot the messenger