T-58 best before date

[SudsyPaul]

So I'm an idiot and I just picked up any packet from LHBS, and I just noticed that the expiration date on the packet is 05-2012

This is almost a YEAR overdue... wtf?

Is this still safe/ok to use?

I'm going to call them and ream them out, tomorrow morning... but I'm 30min into my boil, so there's not much I can do, right now :|

 

[nmfree]

Why wouldn't it be safe to use? It's not like the sterility of the packaging magically disappeared on June 1st of last year.

The only problem that you might run into is underpitching, since yeast viability decreases over time, but I wouldn't worry about even that.

 

[Calder]

Was the pack in the fridge at the LHBS? Did you store it in the fridge? If the answer to both questions is yes, then you are fine.

At room temperature dry yeast looses about 20% or more viability per year. I suspect the use by date s based on that and worked out to be about 50% of the cells to still be viable.

If stored in the fridge, dry yeast looses about 4% viability per year; so even after 10 years you will still have more than 50% viability.

If it was stored cool, you do not have a problem.