A simple test, known as proofing ... Read more: 19 Tips You Need To Bake Better Muffins To proof active dry yeast, which is granulated, pour ½ cup of water that is between 90 and 110 degrees ...

In those cases, my dad would add a bunch of extra yeast and hope for the best. Do you do this as well? To learn more about how to test yeast that may be past its usefulness, I spoke to an expert.