I am doing my first yeast starter ever and am using a stir plate. I entered my numbers into both and came up with two very different results for viability. Yeastcalc gave me 89% which was enough cells ti cover my yeast requirement. On Mr. Malty it gave me a 71% viability and needing two packs to get the right count. The yeast is a Wyeast 1968 London esb. Mfg. date was January 13. Anybody have a preference as to which one they trust more? The guy at my LHBS said to use one pack as a starter and add the other one when I pitch. Three different answers for one starter. I hope it gets easier.
yeastcalc vs. mr. malty
- Thread starter mike024
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Just for kicks, enter an older date into Mr. Malty. It has been known to give you results that are crazy, like needing more starter than you have wort in the fermenter. The yeast calculators are not perfect. Nobody can predict the exact condition the yeast has been through between manufacture and your starter so your yeast may be much more viable than predicted or it could be mostly dead cells. It also would depend on the amount of oxygen you get dissolved in your wort before pitching as the oxygen controls how much the yeast can replicate. (simplified, I know)
LLBeanJ
Well-Known Member
They both have their strengths and weaknesses. I use yeastcalc to make/step-up starters and Mrmalty when I am re-pitching slurry. If starting with a fresh vial or smack pack, go with yeastcalc's numbers and you'll be good.
mike024
Well-Known Member
Thanks guys. I have it stirring at the moment. Is there anything specific I should be looking for to know whether it is finished or not. Right now it looks like spinning beer with a foam cone over the vortex. Are the yeast supposed ti be doing anything visual here. It seems underwhelming. I hope I am doing this right.
The trouble with the viability calculations is that there'e simply no way for them to accurate. Yeast stored for three months at 40ºF will be healthier than yeast stored for three hours in a hot delivery van. Mr. Malty is much more conservative in this respect than yeastcalc. Which is more accurate, ultimately, depends on your situation.
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