To “proof” yeast, first dissolve the sugar (about 1 tablespoon for each 2 cups of liquid) or other sweetener in warm water (about 95°F) and then add your yeast. Wait several minutes for it to dissolve and begin to “work,” or develop tiny bubbles. If it doesn’t show signs of life, discard it and try another batch. Because yeast doesn’t like salt, add it after the yeast is “proofed.”