White Labs PurePitch's decay per 30 days, as a fraction remaining.
White Labs publish their own figures for the pouch: about 99 % viable at one
month, 98 % at two, 90 % at three, 84 % at four, 79 % at five and 72 % at six,
the month its best-by falls on. That's much gentler than the liquid default
of 0.79 per month, which comes from the vial era. That figure would put a
five-month-old pouch at 31 % and size a starter for more than twice the
cells it needs.
Their curve is flat for two months and then falls, which no single
exponential matches. 0.946 passes through the six-month point
(0.716^(1/6)). Before that it reads a little low (85 % at three months
against their 90 %), so any error is toward a slightly bigger starter,
never a smaller one.
White Labs PurePitch's decay per 30 days, as a fraction remaining.
White Labs publish their own figures for the pouch: about 99 % viable at one month, 98 % at two, 90 % at three, 84 % at four, 79 % at five and 72 % at six, the month its best-by falls on. That's much gentler than the liquid default of 0.79 per month, which comes from the vial era. That figure would put a five-month-old pouch at 31 % and size a starter for more than twice the cells it needs.
Their curve is flat for two months and then falls, which no single exponential matches. 0.946 passes through the six-month point (0.716^(1/6)). Before that it reads a little low (85 % at three months against their 90 %), so any error is toward a slightly bigger starter, never a smaller one.