Beer Forum

Hello.

Has anyone with a microscope and hemocytometer tested which yeast calculator is correct or closest?

Mr Malty has a stir plate factor of 1.55, Beersmith is 2.66, and yeastcalc.com is 2.25.

Thanks!

Unfortunately there is no way to know for sure without doing a count every time. Every starter is unique. There's just a lot of natural variation. I have found that my beers come out pretty good with a 2L starter from one pack of yeast with intermittent shaking even though Mr. Malty tells me that I need a 3 or 4 L starter. I would use the Mr Malty factor of 1.55 but don't sweat it if you come up a little short.

As Zigg said, it will vary, especially if your process is variable. If you get consistent in how you handle your yeast, you may be able to get a good feel for what gives you the amount of yeast you want... growth factors, etc. are all just numbers. That being said, JZ's would give you the most conservative, and I doubt you would come up short using his, while the others may give you an overestimate some of the time.

Thanks guys. I am going to split the difference and rahahb. Is that how you write it? lol

I've done many starters with many yeasts and usually get 75% of what Mr.Malty predicts according to cell counts with my process and equipment. Doesn't seem to matter 2L vs. 5L or different inoculation rates. Only once have I seen 100% and it was the only time I've counted a WLP007 starter. The only way you'll know how your equipment compares is by doing cell counts yourself. I've done simple starters too and they all seem to match Mr. Malty's estimates. Brett strains are a different story, they go nuts at 2.5 times the amount of doublings as sacch.