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General Category => Yeast and Fermentation => Topic started by: yso191 on August 06, 2014, 05:10:46 PM

Title: Repitching slurry
Post by: yso191 on August 06, 2014, 05:10:46 PM
It seems I am a little tardy in my research.  I brewed an IPA with Wyeast 1968 on June 5.  I collected the yeast from my conical by discarding the first hard packed yeast, then collecting about 1.5 cups of what came out next.  I then put it in a sanitized Mason jar and stored it in the fridge.

That is only 2 months but Mr. Malty has my viability at 10%.  I brew tomorrow.  How would you handle this?

Here is the slurry: http://s787.photobucket.com/user/yso191/media/AHA/8501DEB1-F252-42C7-94C6-A32D44F9439B_zpsyhrzg2mr.jpg.html

(I would imbed the pic but that button hasn't worked for me for some time)
Title: Re: Repitching slurry
Post by: klickitat jim on August 06, 2014, 05:13:58 PM
I would make a starter and pitch day after tomorrow
Title: Re: Repitching slurry
Post by: 69franx on August 06, 2014, 05:47:02 PM
The numbers on Mr. Malty are scary here for someone who has not done any harvesting and re-pitching. Looking at your pic, you have about 1/2 cup of slurry or about 118mL, at 10%. Using those, Mr. Malty says you need 1034 mL for 5 gallons of 1.065. May need a couple steps. But Im sure someone with more re-pitching experience can allay those fears
Title: Re: Repitching slurry
Post by: morticaixavier on August 06, 2014, 05:51:46 PM
have you played around with the thickness setting and the non-yeast setting?

If you have pretty thick pretty clean yeast you may not need as much. also, I would be somewhat suspect of the viability calculations. that seems fairly steep falloff.

I'd pitch it and see what happens. but I'm a risk taker
Title: Re: Repitching slurry
Post by: ynotbrusum on August 06, 2014, 06:05:12 PM
I agree with Mort on this one - storage under the beer should help it in terms of viability.  Or you can make a starter - not stir it at all, use an airlock and keep it just above the pitching temps while it ferments the wort and then pitch it at high krausen without decanting.  Or just get some dry yeast as a standby in case the stored yeast doesn't take off for you.
Title: Re: Repitching slurry
Post by: kylekohlmorgen on August 06, 2014, 07:57:18 PM
If you have to make a starter anyway, what's the point of using slurry? ($7 savings for the yeast pack?)

Even if you prop up a bunch of healthy cells with the few that are viable, you'll still be carrying over a bunch of dead yeast. Why risk the entire batch?

Either make a starter with a new pack, or use dehydrated S-04; both are much healthier options than old slurry.
Title: Re: Repitching slurry
Post by: Slowbrew on August 06, 2014, 09:21:17 PM
I just pitched around 3 oz. of 1056 slurry into a 1qt starter (1 gallon jar) last week.  It foamed right over the top in about 12 hours.  It's been working away furiously in ale since Saturday.

I bet you'll be fine, just dumping in the slurry you have.

Title: Re: Repitching slurry
Post by: woodlandbrew on August 13, 2014, 12:00:59 AM
Cell counts I have done show that Mr. Malty assumes the worst for viability.  In the fridge viability drops very slowly.  See here for details: http://www.woodlandbrew.com/2012/12/refrigeration-effects-on-yeast-viability.html