Reusing yeast - wash or no wash?

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Sidman

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So I am just finishing packaging a cream ale and want to do another. I prepared a starter with 3 yeast packs wlp 80 (two were close to exp and another was expired) for the first 10 Gallon batch. This time I remembered to cool the batch and dump the trub prior to pitching. I hit the wort with a good full minute of oxygen and the batch took off like a rocket. Fast forward to packaging and I now have two pint sized jars filled with very thick yeast. So I was going to try my luck at reusing this yeast and basically I seem to be confusing myself as to whether or not to wash. It looks pretty clean and my next batch will be two days from now so I was wondering if I should just go ahead and pitch half of one of these pints? I don't think a starter would be needed right? just keep this in the fridge, let warm to room temp before pitching?

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Sidman

Sidman

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I'm no authority but when I looked in to this recently, lots of accomplished folks were skipping the wash, so I am too.
Feel like I am going to do the same. Are you planning on using yours straight or making a starter?
 

jimmykx250

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No wash required in my opinion. That jar is more than enough yeast even for another 10 gal mid range gravity.
 
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I'm going to start by using the slurry straight and skipping the starter, provided I have enough slurry to do the job. How many cells per mL though? There is guidance on this page and it ranges from 1 to 4.5 B/mL depending on how compacted the slurry is.

http://www.mrmalty.com/calc/repitch.html

As of today I have collected 3 jars but haven't actually USED any yet, though I am new to this.
 

IslandLizard

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There's probably some fine trub and proteins mixed in. I doubt washing (or more accurately, rinsing) that yeast slurry would separate them anyway.

Just estimate the cell count and pitch. Rule of thumb is to pitch 1/4 of a saved yeast cake. If it's older than say 2 months (stored in fridge), many will advise to prepare a new starter. I've pitched saved cakes after being 4-6 months in the fridge. Just pitched some extra, but not quite half of the original cake.
 
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Sidman

Sidman

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There's probably some fine trub and proteins mixed in. I doubt washing (or more accurately, rinsing) that yeast slurry would separate them anyway.

Just estimate the cell count and pitch. Rule of thumb is to pitch 1/4 of a saved yeast cake. If it's older than say 2 months (stored in fridge), many will advise to prepare a new starter. I've pitched saved cakes after being 4-6 months in the fridge. Just pitched some extra, but not quite half of the original cake.
Thanks much...I likely have more yeast as I just pulled off the two pints so far. That rule of thumb really helps out.:mug:
 

IslandLizard

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Thanks much...I likely have more yeast as I just pulled off the two pints so far. That rule of thumb really helps out.:mug:
As @Horseflesh said, per Mr. Malty a saved slurry will contain 1-4.5 billion cells per ml. Although that's a wide range, an educated estimate can be made.

If the cake is very trubby, it will be on the lower side. If it's very clean, like yours is after a pre-pitch trub dump, lean toward the higher side, probably in the 2-3 billion cells/ml range, possibly more. If you need 800 billion cells for your new 10G pitch, 270-400 ml of that slurry should suffice. Even a 3x overpitch has no negative effects on the resulting beer, usually. Where some stressing is needed, stay on the lower pitch side.

Good oxygenation helps leveling that field too.
 
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