So is it 6, 10, or 20 billion?

[capt82]

Seems to be different info regarding dry yeast cell counts per gram. One in particular is US-05. Mr Malty says 20 billion cells per gram and the manufacturer says 6 billion per gram.

I just made an IPA (1.062 OG) and just decided to use 11.5 gram packet for a three gallon batch just because it sounded right. BF says I need 130 billion cells. So if Mr Malty is correct, I over pitched by 100 billion cells. If the manufacturer is correct, I under pitched it by 61 billion cells.

The activity was amazing and the trub looked as if it was boiling inside the carboy for days. Based off the crazy activity, I would think if any, it was over pitched.

These pitch rate calculators are worthless unless you know the amount of yeast cells per gram. Is it just me or is that the closest to accurate as it gets?

 

[kaconga]

You could get a microscope and perform your own counts. Personally I just go with Jamil's numbers and call it a day. He was one of the people who literally wrote the book on beer yeast.

 

[jro238]

Interesting that there is such a big difference. I trust Jamil in most things but if the manufacturer tells you how many cells to expect, I would probably trust them. This being said, when I occasionally use dry yeast in a 5 gal batch I just pitch 1 rehydrated pack regardless (assuming OG is below 1.070 or so). If it is slightly underpitched then oh well and it is so hard to overpitch without throwing in a whole yeast cake that I don't worry about it.

 

[tally350z]

Alot has to do with the re-hyrdration process/temps. The 6B count from the manufacturer is the guaranteed minimum. Check this article

 

[kaconga]

Alot has to do with the re-hyrdration process/temps. The 6B count from the manufacturer is the guaranteed minimum. Check this article

Awesome article. As us-05 says to sprinkle directly on to wort then the 6B count makes sense.

 

[capt82]

Thanks tally350z,
That is a good article. I will follow those re-hydration directions next time assuming I'm getting 20 billion count per gram and see if it works for me. Seems like it works for the manufacturer to sell me two/three packs of yeast to pitch directly in my wort rather than 1 pack done properly.


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