rest for a short time. The minimum weight of water required may be calculated: .

Yeast viability can be tested by mixing yeast in warm water and sugar, and following a short rest period during which the cells first accommodate to the environment and then begin to grow, a layer of foam is developed by the action of the yeast, a sign of primary fermentation and live yeast. Typically 60 ml ( cup) water at 105 - 115 °F and 2 g ( teaspoon) of sugar are used, or expressed differently,