Matching yeast temp to wort temp

[Zigs6]

During my most recent all grain batch I hydrated a couple of dry yeast packs in some warm water. Afterwards it dawned on me that I was not anywhere close to matching the temperature of my yeast and wort. The yeast would have been around 80 degrees and my wort temp at the time was 50 degrees for my lager. Can anyone chime in with their experiences with this? Conventional wisdom would tell us not to do this as it may shock the yeast. It’s already fermenting but I could not find much info on this at all. What are the ramifications if any for this mistake. It wasn’t my intention but merely an afterthought.

Cheers

 

[homebrewer_99]

Chill the yeast and wort to the starting temperature. When they are within 10 degrees of each other it'll be OK.

 

[RPh_Guy]

I think there are more reliable ways to kill yeast than suddenly dropping 30 degrees.

IF you rehydrate, and IF you use warm water to do it, the BEST way is to add wort to the yeast every 5-10 minutes to gradually reduce (no more than 10°F at a time) to wort temp after rehydration is complete. Or so they say.

 

[flars]

AS @RPh_Guy said. Bring the temperature of the rehydrated yeast closer to the temperature of the wort by adding wort a little at a time to the rehydrated yeast. This is called attemperation. More information here.
http://www.lallemandbrewing.com/products/brewing-yeast/

 

[couchsending]

You just created some more lag time by shocking the yeast, not a big deal but not advisable.

What yeast did you use? Fermentis recommendation 70-77 for rehydration temp for their lager strains. 15-30 minutes settling plus 30 minutes of stirring etc will usually get you closer to pitch temp unless you’re brewing somewhere hot which I assume since it’s July is probably the case. Attemperation is the way to go in this case.

 

[Zigs6]

I’m in Phoenix and I used 34/70. Let it be written that I chilled a 10 gallon batch of wort down to 48 degrees in Phoenix in the middle of July. I think I was more excited about that so I was so happy I just threw it it in there after oxygenating without thinking about the temp difference. Other than an increased lag time, any other worries? It was going pretty strong after 30 hours so it didn’t seem too bad.

 

[RPh_Guy]

RDWHAHB
All is well.

 

[Steveruch]

Save yourself a step next batch and pitch direct without rehydrating.

 

[Zigs6]

Save yourself a step next batch and pitch direct without rehydrating.

That is a definite yeast killer.

 

[Steveruch]

That is a definite yeast killer.

it can't be that bad; far too many brewers have success doing it that way. At least one of the dry yeast manufacturers now says to not rehydrate.