Need opinion on yeast

[jmartie13]

My schedule changed at the last minute and I have time to brew this weekend. I have the ingredients for an Imperial IPA I was planning on doing, but, I didn't have time to make a starter. The recipe calls for a pitch rate of 275 billion cells. I have two smack packs and I also have three mason jars in the fridge with some yeast settled on the bottom from my last batch. All the same yeast strain.

I guess my question is should I suck it up and buy another yeast pack, or could I decant the yeast in the fridge and add it in the wort with the two smack packs? could I make a small starter today for tomorrow? Any opinions would be great! thanks

 

[stpug]

decant the yeast in the fridge and add it in the wort

If you have in the realm of 200+ml of yeast in your jars then that's PLENTY to ferment that batch. Save the smack packs for your next brew.

 

[jmartie13]

Thanks for the response. Do you know how to tell how much viable yeast is in the settled yeast? There's got to be some ratio of viable yeast to amount collected. I've read that there's 20 billion cells per gram, but I don't have a gram scale.

 

[stpug]

In water: 1 gram = 1 ml. Yeast would certainly be different.

I use an estimate of 1-4 billion viable cells per milliliter.

A White Labs vial is ~30ml, and it only comes ~1/2 full (i.e. 15ml yeast) and they claim 100 billion viable cells at packaging for a breakdown of 6.67 billion cells per milliliter. But their stuff is super clean and concentrated (i.e. no waste material).

So assuming 1-4 billion per milliliter in collected yeast is reasonable in my book, especially if you go low like 1-2 billion per milliliter. I assume 2 billion/ml for washed yeast, and 1 billion for yeast slurry.

You should be able to estimate how many ml you have knowing that 1 cup is ~240 ml, and then using the "billions of cells per ml" of your choice.

 

[jmartie13]

Perfect, thanks.