Making a yeast starter using best by date

[private4587]

I have just bought a pack of Wyeast 1469 and i am wanting to overbuild my starter to keep some as my house yeast. My problem is that the software i use for calculating my overbuild relies on the mfg date but the new wyeast packets come with the best by date. How do i get the mfg date from this to enable me to work out yeast viability

[McMullan]

You don't. It's not really recommended to attempt to extrapolate from assumptions based on bollocks. If you plan to store yeast, do it at a very small scale, millilitres. Then build up when needed. No need to 'overbuild' a starter to hold some back. If you want to figure out yeast viability get a microscope. Otherwise build up from little and confidently assume over 99% viability. Simple really.

[MashBag]

It's not really recommended to attempt to extrapolate from assumptions based on bollocks.

I might have to steal that! Brilliant

[IPA]

Follow McMullan's advice and you wont go wrong.
Or if like me you are not a chemist you could try this method.

viewtopic.php?f=2&t=78251#p812576

[f00b4r]

The best before date is 6 months after the manufacturing date on the outer pitch packets.
That said, following McMullan’s advice on building up from a smaller amount in proper steps improved my fermentation’s, even working to invigorate expired yeast.
IPA’s method on collecting yeast from an active fermentation works well too, it’s a good source to build up from and it’s easy to check the “beer” after for off flavours, before using to create a new starter.

[MashBag]

IPAs method is storming. I did loads a few years ago. Kept them in a freeze and then just lobbed them in. No starter required.

Call me a hooligan...

[guypettigrew]

IPAs method is storming. I did loads a few years ago. Kept them in a freeze and then just lobbed them in. No starter required.

Call me a hooligan...

Seriously? You collected the fermenting beer and froze the stuff. And it worked with no starter?

Astounding.

Guy

[MashBag]

100%
Better still there was no discernable lag.
Ps. Lobbed in from frozen, in the bottle.

[guypettigrew]

This is a late April fool, right?

Guy

[MashBag]

Nope.
Yeast have managed for years (millions) without gycol washes / stainless steel / harvesting / slants and all other manner of cockery..... And without human intervention!

[McMullan]

Fresh/wet yeast (Saccharomyces cerevisiae) cells generally don't like being frozen, even when done properly using standard lab protocols. There's always going to be a significant drop in cell viability due to stress of a freeze-thaw cycle. Most die due to ice crystals rupturing the cell. Ouch! What a horrible way to go! Brewing (domesticated) strains haven't been around for millions of years and have likely drifted away from being as stress-tolerant as wild types. Kind of mollycoddled by friendly brewers. In nature, they'll be long dormant, with a low water content and conditioned by natural cryoprotectants, like glycerol and trehalose, therefore more tolerant than domesticated lightweights, before winter (natural selection) arrives, in temperate regions, but there is still going to be a lot of mortality. Perhaps one reason why they are so rarely isolated from natural habitats in areas with seasonal freezing? I'm not aware of any endemic S. cerevisiae populations surviving in Antarctica or the Arctic, although, obviously, there is a lack of habitat (e.g. tree refuges) to support survival of S. cerevisiae populations over winter at the poles. The Great Antarctic Brewing Company? Doesn't sound right, does it?

[MashBag]

The Great Antarctic Brewing Company? Doesn't sound right, does it?

LOL. There would always be a s stool at the bar!

No disagreeing with anyone. Just I have done this - it works. Try it you might like it.