Effects of other ingredients

• Salt weakens structure as its ions Na+ Cl- compete for bonding sites on the unfolded proteins. It's best to add salt to the other components of a dish rather than the foam itself.
• Sugar both hinders and helps foam making. When added early, it delays foaming and reduces the ultimate volume and lightness. At this point, the sugar interferes with the unfolding and bonding of the proteins. The syrup-egg mixture is also heavier and harder to spread into bubbles. It takes twice as long to foam. However, sugar improves foam stability by slowing down drainage from bubble walls. In the oven, dissolved sugar delays moisture loss until after ovalbumin has had time to coagulate and reinforce the foam. Sugar also adds its own reinforcement to the structure in the form of cotton-candy-like strands of dry sugar. Most times, sugar is added to the egg whites after the foam has already begun to form, though sometimes its added at the beginning for a more firm, dense foam.
• Water in small amounts can increase the volume and lightness of foam, but since it thins whites, it is more likely that some liquid drains from the foam.