I've got an APA in primary now, been in there for 4 weeks. Planning on bottling it tonight. Fermented with US05 sample is very good, anyway question is, i'll be brewing up an IPA tomorrow morning. Anyone else just scoop out about 1/3 of the yeast cake and pitch into a new batch? Is this frowned upon?
Slurry
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I always collect the slurry. Store it in the fridge in mason jars, and pitch about a quarter of the slurry the next time I use that yeast. If I use it within a month, I just straight pitch, if longer, I'll make a starter.
Lots of people use it.
I usually wash the yeast before pitching (not always). I never do it when I collect it since I end up throwing most of it away, and it would be a wasted effort.
Lots of people use it.
I usually wash the yeast before pitching (not always). I never do it when I collect it since I end up throwing most of it away, and it would be a wasted effort.
Here's a thread with some good information: https://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/
I've roughly used Bob's formula many times and it's always worked out great. I usually add a little more yeast than he calls for (usually 1/4-1/2 cup more). But honestly, about 1/4-1/3 of the yeast cake is probably just fine.
I've roughly used Bob's formula many times and it's always worked out great. I usually add a little more yeast than he calls for (usually 1/4-1/2 cup more). But honestly, about 1/4-1/3 of the yeast cake is probably just fine.
Pitching slurry usually works great, but pay attention to your pitching rate. There is a calculator for estimating the amount of slurry to pitch at www.mrmalty.com
For 5.25 gallons (20 litres) of a 1.050 APA you need about 185 billion cells. If the characteristics of your slurry are in accordance with the default settings of Mr. Malty's calculator, you need to pitch 91 ml of slurry (1/3 of a cup). So 1/3 of your yeast cake from your previous batch would probably be waaaaayyyy overpitching.
Fool around with the calculator a bit. It's a great tool!
For 5.25 gallons (20 litres) of a 1.050 APA you need about 185 billion cells. If the characteristics of your slurry are in accordance with the default settings of Mr. Malty's calculator, you need to pitch 91 ml of slurry (1/3 of a cup). So 1/3 of your yeast cake from your previous batch would probably be waaaaayyyy overpitching.
Fool around with the calculator a bit. It's a great tool!
I use slurry and get six or more batches out of the yeast. The problem with Mr. Malty is you don't know how much yeast you have. A lot of it is beer and trub. The calculator is just a WAG. As much as half of your cake will be fine in an IPA. I usually get a a pint to a quart of slurry.
One would think a calculator that can be adjusted to account for the specific characteristics of your slurry is still superior to just winging it.
I can do just fine without it, after all if I have to guess how thick it is the answer is only as good a my guess anyway. One cup of the slurry harvested off the top part of the cake is enough for about any beer. A half cup of it works better than a pack of dry yeast. But then when I use it it's not a month old yet.
Some things I've noticed about Mr. Malty just don't click. I've pitched slurry and hydrated dry yeast side by side that calculated the same amount and the slurry started faster and fermented stronger. And I've made shaken starters that produced much more slurry than the predicted yeast numbers would suggest. So I've decided to just go with what I know works and relax. Keep in mind yeast are more like hand grenades than horse shoes.
Some things I've noticed about Mr. Malty just don't click. I've pitched slurry and hydrated dry yeast side by side that calculated the same amount and the slurry started faster and fermented stronger. And I've made shaken starters that produced much more slurry than the predicted yeast numbers would suggest. So I've decided to just go with what I know works and relax. Keep in mind yeast are more like hand grenades than horse shoes.
just for an update. pitched about a cup of slurry to my 1.070 IPA and took off like a rocket within 6 hours. May try this one more time with my next batch. I realize US05 is dry and cheap, but hey $4 is still $4.
