Just past the stiff-peak stage, the foam is even firmer, takes on a dull, dry appearance and crumbly consistency, and begins to leak some liquid, so that it slips away from the bowl again. At this “slip-and-streak” stage, as pastry chef Bruce Healy describes it, the protein webs in adjacent bubble walls are bonding to each other and squeezing out what little liquid once separated them. Pastry makers look for this stage to give them the firmest foam for a meringue or cookie batter; they stop the incipient overcoagulation and weeping by immediately adding sugar, which separates the proteins and absorbs the water. They also start the beating with about half the cream of tartar per egg that a cake or soufflé maker will, so that the foam will in fact progress to this somewhat overwhipped condition. Past the slip-and-streak stage, the foam begins to lose volume and get grainy.