Yeast past expiration date.

Dwhite · #1 03-12-2012, 04:14 PM

Not a question just an observation.

Yesterday I put together a show mead with some wild blueberry honey.

After getting everything secure in the primary I started cleaning up and noticed the expiration date on the yeast package was 1/2011. This was over a year past, still started, and is merrily bubbling away. A little worried until I got home this evening and saw it working.

Yeast was 71B-1122

Need to manage my supplies better.

All the Best,
D. White

TAKeyser · #2 03-12-2012, 04:19 PM

I think we've all run into pulling a pack out of the fridge only to find we haven't been paying attention to the dates as closely as we should.

Braxton · #3 03-12-2012, 04:34 PM

I've used dry yeast that is past its expiration date before. I usually double my normal pitch rate when I do. But it still seems to work well. Man, I'm cheap.

Chevette Girl · #4 03-12-2012, 04:42 PM

I at least make sure it's doing something after rehydration before I pitch it, if it's not doing anything obvious I add some must as if I was making an acclimated starter...

I keep my yeast refrigerated so it probably extends their viability for at least a couple months but I do try to use everything before it expires.

I did underpitch once with a packet of yeast that was expired by a couple months and hadn't been refrigerated (the packet that came with a wine kit that took a while for me to get to, survived at least one summer in my kitchen) and it took a while to get going and wasn't as quick as most wine kit fermentations I've done but it did eventually finish where it was supposed to.

fatbloke · #5 03-13-2012, 01:17 AM

Dry yeasts in original pack, is pretty much bomb proof.

Expiry dates are added as its considered as a food product, hence the legal device of an expiry date, for the makers CYA.

I just make a starter to confirm the yeast viability.......

hepcat · #6 03-13-2012, 08:12 AM

Quote:

Originally Posted by Chevette Girl

...
I keep my yeast refrigerated so it probably extends their viability for at least a couple months but I do try to use everything before it expires.

Didn't know that. I should be keeping my dry yeast packs in the fridge? Right now I've got them stashed in a cool dry closet.

TAKeyser · #7 03-13-2012, 10:04 AM

Quote:

Originally Posted by hepcat

Didn't know that. I should be keeping my dry yeast packs in the fridge? Right now I've got them stashed in a cool dry closet.

Definitely keep them in the fridge. Every LHBS I've ever been to in the 4 states I've lived store them that way.

Dwhite · #8 03-13-2012, 03:53 PM

This had been stored in the fridge.

This batch is really rockin' and rollin' too. Glad the yeast worked.

All the Best,
D. White

Braxton · #9 03-13-2012, 04:50 PM

There is a drop off in viability with age for sure, though I think it would take a long time to be completely dead if it were kept refrigerated. One of the yeast manufacturers has some handy guidelines for the % drop off in viability over time, but I don't remember which one (maybe Lalvin?).