Calculating Steps in a starter

Ingredients
1

I am making a 15 gal batch of Kolsch using WY2565.  My pack was a few months old and Mr. Malty calculated it to be around 25% viability.  I made a 500 ml starter at 1.040 and put it on the stir plate.  I let it ferment out for a couple days, activity was slow but evident.  After I figured it was just about done, I added another 1500 ml of 1.040 starter and it took off like crazy (did not decant, just added more).

I cold crashed it for several days and decanted the very clear beer off the top today.  I would estimate that there was  100 ml or so of yeast, not really sure how to tell since my flask isn’t graduated that low.  I added another 1000ml of 1.040 wort and fermentation went wild, huge thick krausen in less than an hour even though it’s on the stir plate.  There is probably 3 inches of krausen.

But, here is my question.  Do you think that there is enough yeast there to do 15 gals?  I have only used Mr. Malty but I really wish that there was a stepping up calculator that would let you work up to the amount you need from a limited number of vials/packs.  I can either do one more decant and add more wort or if there is enough it can go right in.

2

Have you tried www.yeastcalculator.com?

Dave

3

No.  Does it have such a service?

4

Yep, check it out.  3 steps.

5

Neat.
Now who do you believe?  Jamil or Kai? According to Jamil I won’t have enough.  According to Kai, I’ll have more than enough (I’m assuming JZainashef would be Jamil and KTroester would be Kai…)

That’s great.  Thanks for pointing me in the right direction.

6

No problem.  Correct in above.  I typically go in between…

Dave

7

I too have been wondering this as well.  Who is more accurate with their information here?  Jamil and Chris White or Kai and his experiments?  Using Kai’s formula would lead me to believe that I have been pitching more than enough yeast while using the Mr. Malty calculator I am sometimes underpitching even though my fermentations are sufficient and effective.  Still trying to figure this one out…

8

Here is another calculator to try out…

http://www.wyeastlab.com/hb_pitchrate.cfm

9

I’ve always had good results being somewhere in the range between yeastcalc and Mr.Malty. I don’t think that either is much more accurate than the other. You want to pitch enough yeast but not way too much. I think the range between them is close enough to get there reliably.