What do I do with expired yeast?

February 19, 2012 2:31 AM

What can you do with expired yeast?

I have two foil packets which expired a year ago, and a canister that expired five years ago.

I don't have enough other ingredients to just experiment (and I really want to make sure the king cake I'm making is perfect as hell), so I'm just gonna buy some more, but I don't want to just throw away this stuff.

Any ideas?

posted by Katemonkey to Food & Drink (8 answers total)

It may still be good. Dry yeast can hibernate a very long time, depending on storage conditions. Try putting some in a bowl with warm water and a pinch of sugar and see if it froths. If so, huzzah! Use as normal. The foil packets will probably still be good - a year isn't that long. Use it in something that won't be a total disaster if it doesn't rise well - I'd try a no-knead pizza dough that gets to sit in the fridge for a day or so. Worst case scenario is that you'll have a thin, crispy crust.
posted by ninazer0 at 2:40 AM on February 19, 2012 [6 favorites]

Try this bread recipe - I made it with some sketchy old packets of yeast from the back of the fridge, and it turned out awesome. Just make sure you initially keep it warm and give it enough time to rise, as it may react slower than fresh yeast.

If you follow that recipe, I recommend reducing the amount of salt. As written, it was a bit much for me.
posted by illenion at 7:40 AM on February 19, 2012 [1 favorite]

Dutch Crunch bread has a topping that is made from yeast (among other things). The topping doesn't rise, so slower/inactive yeast might work for that.
posted by dogmom at 7:59 AM on February 19, 2012 [2 favorites]

Best answer: I throw mine in the compost pile. I've had way too many loaves of bread that just didn't rise to worry about wasting a dollar's worth of bad yeast. If the proofing doesn't prove it good, toss it.
posted by CathyG at 10:24 AM on February 19, 2012

I would use it anyway. As CathyG points out above, you'll know whether it's effective or not by whether or not it proofs.
posted by bunderful at 11:16 AM on February 19, 2012

In my experience, yeast viability continues to decline over time - the longer, the larger the percentage of the total packet that will be nonviable (maybe assume 10% is nonviable at start and maybe 20% at a year?). We have had disasters with old yeast and bread when it was time-critical, but I reckon these would have been mitigated with time (the remaining yeast continuing to multiply). So if you have time to spare, I'd give it a go on something less critical than your king cake.
posted by sagwalla at 12:09 PM on February 19, 2012

Response by poster: The can (expired 2003! Christ!) has been dumped into the compost pile.

The year-out-of-date packets will be kept for an attempt at Tiger Bread. Or pizza dough. Or crumpets. Something where I don't have to worry too much.

The king cake (made with new yeast) is now cooling on racks in the kitchen. NOM.
posted by Katemonkey at 12:47 PM on February 19, 2012

I use expired yeast successfully all the time, but 2003 is beyond anything I've tried.
posted by Obscure Reference at 12:49 PM on February 19, 2012