Checking yeast for freshness is a crucial step in baking to ensure the success of your baked goods. Fresh yeast is active and will produce carbon dioxide gas, which causes the dough to rise. Old or inactive yeast will not produce enough gas, resulting in dense, flat bread.
There are a few simple ways to check the freshness of yeast. One way is to proof the yeast. To do this, dissolve the yeast in warm water with a little bit of sugar. If the yeast is fresh, it will foam and bubble within a few minutes. Another way to check the freshness of yeast is to sprinkle it on warm water. If the yeast is fresh, it will float on the surface of the water.