Using Outdated Yeast

You can buy fresh yeast CHEAP at Sam's Club, B J's and like stores. It comes in big bags and is less than 1/10 the cost of the triple packs. Buy it there, open and put some in small airtight package in fridge for immediate use and put rest in ziplock in freezer until needed.
Measure what you need, when you need it and put rest back. You will have yeast for MANY bakings.

The best bargain I ever found was outdated yeast. I bought it at a flea market. The man was selling it Three Triple packages for 50 cents. I pointed out that it was outdated, and asked him if it had been stored properly, explaining to him that it might not be any good. He said he bought it at a food auction and didn't really know anything about it. Then told me he would sell all he had to me for just what he paid for it. What a bargain it turned out to be!! I took a chance for $2.00 and carried home 185 triple packages that were 6 months out of date. I took 3 or 4 packs at random and checked them by dissolving them in warm water with a little sugar added. They all were good. I then put them in ziplock bags and put them in the freezer. That was in July of 1998, and I am still using from them. In fact have a loaf of bread almost ready to come out of the oven this morning.

I teach cooking for a living. Don't buy out dated yeast. yeast is a little plant and it does not regenerate after the use by date. You would be better off buying good fresh yeast and freezing it for the time between dates in an air tight container. Let yeast warm to room temprature before using. You'll have great baked goods and they won't taste yeasty. Out dated yeast will not rise with good resalts. It really doesn't makke good sense to waste your money and time on poor old products.

I assume you are referring to dry yeast packets. Keep them in the freezer indefinitely! Sprinkle into 1/4 cup lukewarm water with a pinch of sugar to activate before using. If it does not foam up after 5 minutes, it is unusable as a leavening.