Oven spring is the quick rising of leavened dough or batter products that is observed in the initial part of baking. In yeast leavened products it is caused by the increase in activity of the live yeasts as the bread warms from the proofing temperature. The dough will continue to rise until the yeasts die when the dough reaches an internal temperature of 60 degrees centigrade. In batters that are leavened with baking powder or foams the rising action is caused by the warming (hence expansion) of air trapped in the substance that emulsified it.