How much yeast do I have? OLD YEAST!

[Jayhem]

I used some of the yeast I harvested off my last IPA for a starter.

I'm planning to brew 11 gallons of 1.067 OG IPA this week.

The yeast was harvested from the fermenter 75 days ago. I had about 1 full cup of thick, white yeast slurry in a sealed mason jar in the fridge.

I made a 3.0 L starter and put it on the stir plate. It took about 10 hours to produce some krausen and it was done after about 36 hours on the stir plate. Now I look to have about 2 cups of thick white slurry.

Any way I can estimate cell counts? I was going to use this for an 11 gallon batch but now I'm thinking I had so few viable cells to begin with that I probably only have enough for a 5.5 gallon batch.

What would you do? I want to brew in a day or 2.

 

[eastoak]

you could count the cells under a microscope but my bet is that you have plenty of yeast in a 3L starter.

 

[Jayhem]

you could count the cells under a microscope but my bet is that you have plenty of yeast in a 3L starter.

Plenty of yeast for an 11 gallon IPA with an OG of 1.067? This is Nottingham Ale Yeast. I may just pitch the starter yeast to 5.5 gallons of wort and a couple packs of US-05 to the other 5.5 gallons of wort to be safe.

 

[eastoak]

Plenty of yeast for an 11 gallon IPA with an OG of 1.067? This is Nottingham Ale Yeast. I may just pitch the starter yeast to 5.5 gallons of wort and a couple packs of US-05 to the other 5.5 gallons of wort to be safe.

you need something like 500 billion cells so, yeah, i'd say a 3L starter is plenty. 1 cup of slurry would have about 500 billion cells. 1 pack of US-05 is plenty for a 5 gallon batch of that gravity.