New to yeast starters

[BobBailey]

Howdy folks. Been brewing for several years now, mostly all grain and never made a starter. Have read enough that I don't actually have a problem with the starter, but a question about building enough to pitch plus enough for another starter. I assume that if I calculate out a proper starter for the brew and up size it enough to produce another 100 billion cells that I can treat the extra 100 billion cells as if it were a fresh vial of yeast when I need it for another starter? Is this true? Can I calculate its viability by age the same as you would a fresh vial assuming it was refrigerated? If not, can anyone tell me how it would differ? Any input sincerely appreciated.

TIA,

Bob

 

[WoodlandBrew]

You've got the right idea. Most homebrewers use with Mr. Malty or Yeast cal for these type of calculations. If you are running your starter for 48 hours and crashing they are fairly accurate, but if you run to completion then the estimates are low. Kai's formula on brewers friend is more accurate if you are running to completion. For viability by date all of them seem to produce a lower viability number than I have measured. There is very little drop in viability when refrigerated.

You can use the calculators, or do the calculation yourself. Balling Observed that number of cells produced is 1 billion cells per gram of extract. That doesn't match the calculators, but it does match my results.

Here is information on viability in the refrigerator:
http://www.woodlandbrew.com/2012/12/refrigeration-effects-on-yeast-viability.html

 

[sky4meplease]

What do you mean by running to completion?

 

[BobBailey]

Thank you very much Steven. Very informative. Have a Merry Christmas!

Bob

 

[WoodlandBrew]

What do you mean by running to completion?

By running to completion I mean allowing adequate time for all fermentable sugars to be metabolized.

 

[trentm]

is 1 billion cells per gram of extract.

I am a little confused about the use of "cells per gram of extract". Are you talking about malt extract? If so, I think a typical a starter uses 100 gram of malt extract per liter. So, are you saying a typical 1 liter starter fermented to completion should contain ~100 Billion cells?

 

[m00ps]

I am a little confused about the use of "cells per gram of extract". Are you talking about malt extract? If so, I think a typical a starter uses 100 gram of malt extract per liter. So, are you saying a typical 1 liter starter fermented to completion should contain ~100 Billion cells?

yes he's saying that a typical yeast strain will produce about that many cells after consuming that amount of sugar. I usually do 1L starters for most of my 5.5gal batches that arent too strong. I know expert will advocate more, but it works for me. Plus I brew like 60% belgians and it helps bring out the esters

 

[WoodlandBrew]

yes he's saying that a typical yeast strain will produce about that many cells after consuming that amount of sugar. I usually do 1L starters for most of my 5.5gal batches that arent too strong. I know expert will advocate more, but it works for me. Plus I brew like 60% belgians and it helps bring out the esters

Yes, that's right. Per gram of extract consumed is more accurate. The extract could be any carbon source that the yeast can metabolize.