Meringues can go wrong in a number of ways. Under- or overbeaten foams may weep syrup into unsightly beads or puddles. Beads also form when the sugar hasn’t been completely dissolved; residual crystals attract water from their surroundings and make pockets of concentrated syrup. Undissolved sugar (including invisibly small particles present in an undercooked syrup that then slowly grow at room temperature) will give a gritty texture to a meringue. Too high an oven temperature can squeeze water from the coagulating proteins faster than it can evaporate and produce syrup beads; it can also cause the foam to rise and crack, and turn its surface an unappealing yellow.