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yeast starter with harvested yeast

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Pdaigle

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Harvested yeast this week and I want to make another batch this weekend. I was wondering if I can make a yeast starter with that harvested yest?
 

BigMack

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Not only can you, you most certainly should. If you harvested yeast from a commercial brew then you need to build up the cell count so that you pitch enough healthy yeast into your beer to do its job.
 

kombat

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He didn't say he harvested it from a commercial brew. In fact, his wording ("want to make another batch") suggests he harvested it from a batch of homebrew. In which case, if it's less than 2 months old, I wouldn't bother with a starter, I'd just pitch 1/2 - 1/3 of the harvested cake directly into the new batch. It will take off like a rocket.
 

BigMack

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He didn't say he harvested it from a commercial brew. In fact, his wording ("want to make another batch") suggests he harvested it from a batch of homebrew. In which case, if it's less than 2 months old, I wouldn't bother with a starter, I'd just pitch 1/2 - 1/3 of the harvested cake directly into the new batch. It will take off like a rocket.
Fair enough, I suppose I shouldn't have assumed he meant commercial. Normally when I hear harvested yeast that is just where my first thought goes.

But yeah, if you're using a harvested yeast cake from a previous batch you should be good to go with just pitching what you've got.
 

kombat

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Whoops, just noticed a typo in my post. I meant to say he should pitch 1/4 to 1/3 of the previous yeast cake, not 1/2. 1/2 would be a wild overpitch. Heck, 1/4 - 1/3 is almost certainly still overpitching, but not (IMHO) by a margin big enough to cause off flavours, and I'd much rather overpitch than underpitch.

I usually collect my previous batch's yeast cake in equal portions in 4 mason jars. I repitch 1 jar per new batch, except for lagers or high-gravity batches, which get 2 jars.
 

Andyoesq

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Whoops, just noticed a typo in my post. I meant to say he should pitch 1/4 to 1/3 of the previous yeast cake, not 1/2. 1/2 would be a wild overpitch. Heck, 1/4 - 1/3 is almost certainly still overpitching, but not (IMHO) by a margin big enough to cause off flavours, and I'd much rather overpitch than underpitch.

I usually collect my previous batch's yeast cake in equal portions in 4 mason jars. I repitch 1 jar per new batch, except for lagers or high-gravity batches, which get 2 jars.
Actually, I was going to harvest yeast for the first time this weekend, and was going to ask this exact question.

Let me know if you see a problem with this plan. I was going to put a gallon of boiled water on the yeast cake, let is sit for about half an hour, decant the yeasty goodness into 4 mason jars. Put three mason jars in the fridge for future use, and throw one of the mason jars directly into a new batch. This should work right? I wasn't planning on using a starter for the same day pitch. Wasn't sure if I would need one for the later fridge pitches
 

brew703

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Whoops, just noticed a typo in my post. I meant to say he should pitch 1/4 to 1/3 of the previous yeast cake, not 1/2. 1/2 would be a wild overpitch. Heck, 1/4 - 1/3 is almost certainly still overpitching, but not (IMHO) by a margin big enough to cause off flavours, and I'd much rather overpitch than underpitch.

I usually collect my previous batch's yeast cake in equal portions in 4 mason jars. I repitch 1 jar per new batch, except for lagers or high-gravity batches, which get 2 jars.
so 1/4-1/3 of a pint jar for a 10 gallon batch?

I brewed a 3 gallon batch of 1.063 over the weekend and pitched 4.8 oz of slurry. Mr Malty shows I needed 131 billion cells.

Assuming 1 oz contains roughly 30 billion cells, I should have pitched 4.37 oz but the slurry I had included hop debris (from dry hopping) so I added a little extra. Within 8 hours fermentation started.

I would think if brewing 10 gallons 1/3 of a jar would not be enough. Assuming an OG of 1.063 and a 10 gallon batch, Mr Malty shows over 14 oz is needed (again assuming an oz=30 billion cells).
 
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Pdaigle

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Whoops, just noticed a typo in my post. I meant to say he should pitch 1/4 to 1/3 of the previous yeast cake, not 1/2. 1/2 would be a wild overpitch. Heck, 1/4 - 1/3 is almost certainly still overpitching, but not (IMHO) by a margin big enough to cause off flavours, and I'd much rather overpitch than underpitch.

I usually collect my previous batch's yeast cake in equal portions in 4 mason jars. I repitch 1 jar per new batch, except for lagers or high-gravity batches, which get 2 jars.
But all depend how many yeast you have in your slurry right? Here's a pic of the jar

image.jpg
 

DurtyChemist

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I would consider either shaking this up and transferring it again after solids drop to the bottom, or decanting more of the water before pitching the whole thing into a starter then just harvesting from the starter. You'd really want to know the volume that beautiful white later is taking up in your mason jar so you could then calculate how many cells you have. Check out the link I posted earlier if you want but I would think the amount of yeast you have in the mason jar pictured below is about the same volume and density of a white labs fresh pitch.

But all depend how many yeast you have in your slurry right? Here's a pic of the jar
 
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Pdaigle

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I would consider either shaking this up and transferring it again after solids drop to the bottom, or decanting more of the water before pitching the whole thing into a starter then just harvesting from the starter. You'd really want to know the volume that beautiful white later is taking up in your mason jar so you could then calculate how many cells you have. Check out the link I posted earlier if you want but I would think the amount of yeast you have in the mason jar pictured below is about the same volume and density of a white labs fresh pitch.
I was told not to do a starter with this harvested yeast
 
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