Stepped Starter Calculations

[BigB]

I was wondering if anybody knows of a decent calculator to estimate the final amount of yeast from starters that were split then stepped. For example, yeastcalc is pretty close to what I want, but it won't let you change any of the variables for the steps besides the size of the starter.

Say you start with a single tube/smack pack of yeast that had a manufacture date about a month or so back which left you with 75% viability... Now you are really starting with roughly 75B cells. So you go ahead and do a 1.5L starter on a stir plate. When that is fully fermented, you cool then decant. The resulting slurry is then measured. Next, you take 1/2 of the slurry and add pitch that into a 1.8L starter. Now do the same with the other 1/2.

Is there any calculators that would make the calcs easier by being able to set the variables such as these all at once? Yeastcalc will somewhat do it, but you have to do it in several steps and add the results.

 

[KaSaBiS]

Huh? Yeastcalc has everything you need IMO. I split upfront. so If I brew 12 gal batches and have a fresh vial, I split it and "start" with 50 bil cells, and change my desired batch to 6. everything is done x2.

if you wanted to split after the first step, take the new total of cells, devide that by 2, and punch that as your viability.

 

[BigB]

Exactly my point. I made the example simple, but like you pointed out, yeastcalc does NOT do what I want - It requires multiple steps. I find it myopic in only allowing variable adjustments in the main step - albeit its better than any of the others I found. I might just make an excel spreadsheet and be done with it.

 

[KaSaBiS]

Im just not sure why you would put any extra time into this. I think his calculator is neat and consise.
all I do with it anyway is jot down each size starter needed onto a post it note anyway to take to the stove.

I would have to imagine you must really make a lot of split step starters after pitching the entire vial in the first step. It takes me approx. 2 min to get any type of configuration punched up then I move on. I do this once a month, and the time spent on changing a field up top in the calc saves me no real time anyway..

Sorry Im no help. Have you worked with the Wyeast step calculator on their site? that may have what your looking for. I know mr. malty doesnt

 

[jhoyda]

Am I missing something?

Step 1: enter viability (75%) and 1.5l starter
Step 2: take resulting cell count, divide by two
Step 3: take resulting number, enter as starting cell count (instead of 100 billion) and 1.8l starter

It took me longer to type that then it would to enter. These are all estimates anyways unless you have a scope.

 

[KaSaBiS]

he wants it to branch it into seperate starters without having to take a calc value and replace starting values. and +1 to your microscope comment. no point in refining an estimate if it will still be an estimate of equal accuracy. I am missing the real convienience factor since it is so fast anyway

 

[BigB]

I know it seems like what I am attempting is simple... but I made the simple example intentionally to keep from writing a long convoluted thread. Yes, a microscope and plates would be nice, but again...just looking for a reasonably accurate estimate. My whole idea here is more of experimentation than anything else. Essentially testing a theory. At $7.50 for a vial of yeast, I was contemplating how to best stretch that money without yeast washing. I don't like yeast washing as I don't have the proper lab equipment to get the quality control I want. Plus, for lagers I like to pitch LOTS of healthy yeast - something I'm not convinced you can get from washing. But, I don't want to buy 4 vials of yeast either for a maibock. Nor do I have the ability to make 4L starters. Finally, to make things really confusing, I am testing what I believe to be my understanding of what Chris White was saying in various chapters of his "Yeast" book (great book by the way). So for me its not a matter of trying to speed up what I'm doing for a particular brew, it s just the simplicity of an "all-in-one" calculator rather than a so-so calculator that does part of what I want....I was just trying to avoid programming my own calculator to theoretically test multiple combinations of variables through multiple steps as I'm not that strong with excel. Finally, no I have not looked at Wyeast's calculator... didn't know they had one. I'll look it up.

EDIT: I checked out Wyeast's calculator... It doesn't do what I want either.