How much slurry

[wolfie7873]

How does one know how much slurry to use for a given gravity and volume of wort?

I've been pretty religious with using dry yeast packets for my brews. Since this is obviously somewhat limiting, branching out into liquid yeast makes sense. The reason I generally don't is because I've gotten some strange results in the past, beers that just didn't taste good and when brewed again with dry yeast were just fine. Happened too many times to be coincidence. I tend to make small batches (3 gal into fermentor) and my theory was that the liquid packs were either too much yeast, or too much leftover starter wort for my beer to ward off changes in flavor profile.

But if I made my own starters I could presumably get around this. Culture a liquid yeast strain, harvest and wash, store under sterile water and use "the right amount" when needed for a brew. Obviously weighing dry yeast is simple enough for determining cell count using published data, but how does one know how much slurry to use for a given gravity and volume of wort?

 

[GernBlanston]

I'm sure there is a better way, but early in my yeast washing development, I took an empty vial, filled it with water to the line where a settled slurry would come up to, then poured it into the quart jar I will be collecting the washed slurry into, and repeated it three more times. This gave me a idea where four vials would fill up to in the jar. All my slurry jars are the same, and I collect slightly more than I need. Its rather hard to over pitch to the point it causes problems. Under pitching is more of a concern. Now I just estimate the slurry. More for big beers. Even more for lagers. If the pitch is large enough, and aerate the well, it can overcome any deficiencies you might have in the wort aeration.

 

[Brew Cat]

I don't wash my yeast , I just pour the trub in a couple mason jars. I use the forum host pitch calculator and never had a problem

 

[Head First]

Not very scientific but I just split a yeast cake from 5 gallon into 2- 5 gallon fermenters. I get some blow off but it ferments the beer in 3-10 days depending on the yeast type. Usually get about 3/4's of a quart of slurry from 1 cake. So first use yeast from a 10 gallon batch(2- 5gallon fermenters) will give me enough for 2- 10gallon batches then enough for 4- tens etc.

 

[Brew Cat]

That translates to about 700ml. So half is half is about 350ml. That sounds about right for an average beer. I've pitched the whole amount for a big beer. The thing I've noticed about slurry is yes it works fast and usually attenuates much better than what is advertised. I think you could pitch less but I would rather over pitch than under pitch any day.

 

[Nola_Brew]

I use the ratio of 30 billion cells to 1 oz of slurry. This is assuming it's straight yeast slurry with no hop debris. If I use slurry that was dry hopped , I usually add an extra ounce or two to compensate. Never had an issue.

 

[wolfie7873]

I use the ratio of 30 billion cells to 1 oz of slurry. This is assuming it's straight yeast slurry with no hop debris. If I use slurry that was dry hopped , I usually add an extra ounce or two to compensate. Never had an issue.

1 oz by volume or weight?

 

[Nola_Brew]

I use the ratio of 30 billion cells to 1 oz of slurry. This is assuming it's straight yeast slurry with no hop debris. If I use slurry that was dry hopped , I usually add an extra ounce or two to compensate. Never had an issue.

1 oz by volume or weight?

I put a jar on my scale and zero it out then pour the slurry.