You’ve had a jar of instant yeast in the fridge for a little while… and you want to bake. How do you know if it’s still active? Here’s the answer…..
To check if instant yeast is still good, perform a quick "proofing" test:
mix 1 teaspoon of yeast with 1 tablespoon of warm water (around 100°F) and a pinch of sugar; if it becomes foamy, bubbly, and forms a dome within 5-10 minutes, it's active and good to use, but if nothing happens, the yeast is dead and should be tossed.