Answer: 

To proof Traditional Active Dry Yeast or fresh yeast, add 1 teaspoon sugar to 1/4 cup warm water (100° to 110°F / 38º to 42ºC). Stir in 1 envelope yeast (2-1/4 teaspoons); let stand 10 minutes. If the yeast foams to the 1/2 cup mark, it is active and you may use it in your recipe. Proofing is not recommended for Quick-Rise™ Yeast.