Mr Malty "Harvest Date"

Northern Brewer General
1

A few yeast questions here:

Primary Question:

When using the Mr. Malty pitch calculator’s “Harvest Date” field…is it best practice to use the date of the most recent harvest (on the logic that many of the yeast cells in the harvest would have been created during the course of the fermentation of the beer that you are harvesting from)…or is it best to use the date of the first harvest for that yeast…which may have been several batches and many weeks back?

Secondary Question:

Mr. Malty is telling me I need 72ML of yeast for a 1044 red ale, based on the harvest date and slurry thickness and whatnot that I have entered. I have at least that amount in a mason jar in the fridge. Does this mean I should A) just pitch that much yeast from what I have in the fridge, B) make a starter that will yield that much (fresher,younger) yeast, or C) take that much yeast and make big starter with it?

I guess my bias would be to take the 72Ml and make a starter to get thing up and running and since I have read in a few places that its is nearly impossible to overpitch at the homebrew scale.

Looking for opinions here.

Thanks all…

2

Use the most recent harvest date. And if the yeast has been stored for less than a month I would generally just pitch it, longer than that I usually make a small starter.

3

Really, it would be best to use the date the beer reached high krausen, because that’s pretty much the point at which the viability starts dropping. If you got lazy and left a fermenter at room temperature for a month, then harvested, your actual viability would be in the 60% range, but the calculator would say it’s near 100%.