can yeast starter be too large

making first ever starter, added vial of yeast yesterday the name escapes me sorry into 1litre of 1040 wort and spun for 24 hours chilled overnight could definately see the yeast at the lower of bottle , decanted wort from above and made a new 1040 wort and added and now have back on the stir plate , definately have activity going on thinking of running for 24 hours.

Question 1: How do i actually know when ive created the maximum amount of yeast from the wort that i can do?

Question2:How do i know that the yeast amount is sufficient other than cell counting under a microscope ?

Question3:Is it possible to make too much yeast? And ruin my beer because of this?

Going to be making a porter kit!
The information that i am after is for the future as well as trying too improve my skills before attempting whole grain brewing.

Thanks all!

If I am trying to increase my yeast count by doing a 2-stage starter then I try to have the wort volume of the 2nd stage to be larger than the first stage. Using the same volume of starter for the second stage may not give you twice the yeast count as the first stage.

Aah I see that would make perfect sence

Here you go.
http://www.mrmalty.com/calc/calc.html

here is my favorite yeast calc...http://www.yeastcalc.com/

I like it because you can do step up starters with it.

The calculators will give you a good estimate but can easily be off by a factor of two. There is no way to really know without a cell count. If you over pitch by a factor of two you will get a fast fermentation, and less of the yeast characteristics. Under pitching will result in a multitude of flavor problems, so when it doubt, over pitch.

If anyone is actually interested in the data I was thinking of doing some experiments to see how close the calculators are to my processes. (Both Mr. Malty and YeastCalc are based on the same set of data produced by White Labs)

WoodlandBrew said:

The calculators will give you a good estimate but can easily be off by a factor of two. There is no way to really know without a cell count. If you over pitch by a factor of two you will get a fast fermentation, and less of the yeast characteristics. Under pitching will result in a multitude of flavor problems, so when it doubt, over pitch.

If anyone is actually interested in the data I was thinking of doing some experiments to see how close the calculators are to my processes. (Both Mr. Malty and YeastCalc are based on the same set of data produced by White Labs)

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So are you thinking the calculation for desired pitching rate is off, or just the estimation of your starting cell count in the pack/vial? I imagine the latter is where error really comes for since loss of viability is probably not nearly so constant from batch to batch n each strain, and certainly not between strains.

The estimation of cells generated by the starter calculator is the largest variable that I see, although the other two are factors as well. White Labs specifies that a vial contains 70 to 140 billion cells, so even if you pitch yeast directly after purchasing it your starting cell count can vary by a factor or two.

WoodlandBrew said:

The estimation of cells generated by the starter calculator is the largest variable that I see, although the other two are factors as well. White Labs specifies that a vial contains 70 to 140 billion cells, so even if you pitch yeast directly after purchasing it your starting cell count can vary by a factor or two.

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I have always wondered about this. White Labs vials average 100 billion cells per vial. But as you said the actual cell count can be 70-140 billion. It seems like there could be a HUGE difference in either direction unless you do a cell count. But how many professional breweries actually do cell counts? I am sure all the large and mid-size breweries do. I seriously doubt many small breweries and brew pubs do.

The bigger the starter is the less the initial cell count influences the final cell count. Using yeast calc for a 1.5 litter stater with 70 to 140 billion cells the final count ranges from 148 to 215. So the initial cells varied by a factor of two but the result only varies by a factor of 1.4. But, of course, there is the growth factor of the calculator that is likely not the same as the real growth factor.

Phunhog said:

But how many professional breweries actually do cell counts?

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That's something I'm curious about. It's pretty easy to do if you have the right tools.