How to Test the Freshness of Yeast 9 Steps with Pictures1. Protect dried yeast from the elements. Sealed sachets or unopened jars protect dried yeast from heat, light, and moisture. However, once exposed to oxygen, it must be kept in a cool, dry, and dark place. Dried yeast may be stored in a cabinet, pantry, or freezer. Ounces Per Pound on this page. Proofing Yeast' title='Proofing Yeast' />This is the best homemade low carb yeast bread recipe that I have found that gets great results every time. Can be baked in a bread machine or the oven. To activate yeast the first step is called proofing and is a way to test the yeast to make sure it is alive and still active. This is accomplished by mixing the. Yeast Basics Learn to Bake.