How Long Before Yeast Unviable?

[meadowstream]

I ran a tube of WLP530 through a couple of growth cycles but the hardware that I expected from Brewers Hardware is delayed by a 3-4 weeks...will the yeast that I have refrigerating at a low temp last for a month or do you think I need to start from scratch again the week before I brew? Thanks for your opinions!

 

[Culbetron]

It will last, but you will have to give it a little extra starter a couple days before you brew to get it active.

 

[kh54s10]

If you use a calculator and make a proper sized starter there is no reason not to go at least 4 generations. The length of time it is viable depends on the storing procedure and sanitation.

mrmalty.com and yeastcalc.com have god information on viability and making starters.

I freeze yeast and have revived samples that were saved for almost 2 years.
I take 5 ml yeast, 5ml glycerin and 10 ml water, mix, chill in the refrigerator, mix again then freeze.

I have about a dozen different yeasts on hand, including some dry yeast when I want to brew but don't have enough time for a starter.

 

[Culbetron]

Oops, reposted for some reason