Repitching question

[zeeke]

I am getting ready to repitch from a harvest of WLP001. I have the harvested yeast in a Nalgene bottle in the refrigerator, and am following Jamil's instructions from the shows. The only part I can't figure out is the temperature of the yeast when you re-pitch. Do I take the whole container out and let it get to room temp, then add room temp sterile water, shake and pitch what i need? Can i then just put the rest right back in the refrigerator again until I am ready to use it? Do these temp swings not affect the yeast viability?
Or can I add refrigerated sterile water to the refrigerated, decanted yeast and then shake and pitch part of the cold slurry into the room temp wort? What is your procedure?

Thanks in advance

[scotchpine]

Well here's what I do. I collect about a qt of yeast cake from fermenter and add equal amout of preboiled water at room temp (both). Shake really well and place in fridge. I remove from fridge a couple hours before making my next starter and losen cap. After my starter wort is boiled, with yeast nutrient, and cooled, I extract the middle layer of yeast with a sanitized turkey baster and put it in the wort at room temp (both). Place on stir plate and let her rip. I also add fermcap. Hope that makes sense to ya.

[brewindruid]

Well here's what I do. I collect about a qt of yeast cake from fermenter and add equal amout of preboiled water at room temp (both). Shake really well and place in fridge. I remove from fridge a couple hours before making my next starter and losen cap. After my starter wort is boiled, with yeast nutrient, and cooled, I extract the middle layer of yeast with a sanitized turkey baster and put it in the wort at room temp (both). Place on stir plate and let her rip. I also add fermcap. Hope that makes sense to ya.

I like this idea, less work then washing it. I am washing 1469 now and it is being a stubborn SOB.
I would either do as above or decant the waste water, pull off the amount you want to pitch let it warm. Meantime do a low SG starter to wake em up, say about three hours before you need to pitch. Put the harvested yeat in the room temp starter, you don't want any temp shock, let em start to work and pitch the whole thing! Don't need much more starter wort just enough to get things moving along.

[Ozwald]

Washing it can be a real PITA, especially getting the pH perfect & using the correct types (& subsequently concentrations) of acid. I don't know a lot of homebrewers who are doing an actually wash on their yeast, for good reason. It's just more trouble than the cost of buying a new pitch if you can't rinse it clean. Depending on how bad the yeast is, the amount of trub or hop residue, several rinses are in order.

I collect a large portion of the yeast cake into a sanitized bottle & mix it up really well. If it's really thick, I'll add a touch of sterilized, de-oxygenated water. You'll get the 3 layers & you're really looking to get that middle layer.

Let it settle out completely, decant as much of the top layer as you can, and transfer into another container, leaving as much of the bottom layer behind as possible. Add more water, swirl & let it settle out again. I repeat until 85%+ is just that original middle layer. You probably won't have much volume left by this point, so do a couple of small starters to build your cell count back up. If you're being really careful you can rinse out a couple times, do a starter to boost the middle layer without much effect on the top/bottom ones & rinse a few more times to help if you lose too much of that middle layer in the rinsing process. I err on the side of leaving too much top/bottom with each rinse to avoid that situation. It's easier to sand a piece of wood to size than to try to whittle it down with a chainsaw & miss.

As for temps, you want to avoid the shock. Since I let it settle out cold to help with layer separation, I don't use room-temp water. Instead, carefully pull it from the fridge to not stir anything up & let it set at room temp for 15-20 minutes. I pull the water at the same time. After 20 minutes they should be close enough where shock won't be an issue and will be significantly easier to separate than at fridge temp.