Any yeast should be kept in a glass mason type jar in the fridge or freezer. Yes, this pic is now, 6 years and still quite viable! Take out what you need, immediately reseal, and back for a cold nap. REALLY the only way to go! I buy in bulk, usually a pound at a time. If it starts getting lazy, I don't feel very guilty for tossing it at $5ish/lb if it lasts for 6+ years! Try it, you won't regret it!!!