The fermentation rate increases up to a temperature of 40.5oC (105oF).1 In order to control the height of the baked good, yeast kill should be accomplished by 50% of the bake time. During baking, yeast starts to die at 55.5oC (132oF). An absolute yeast kill is at 60oC (140oF).2
Used as a QC tool, the baker can control the height of the oven spring with strict adherence to yeast kill at about 50% of the product. The importance of predicting and controlling yeast kill will prevent issues with product height. This includes:
- Buns that break and shred on just one side, causing sloped crowns
- Prolonged oven spring, that either causes an oversized product, that cannot be bagged; or one that causes a huge collapse after cooling.
Minimize oven spring with yeast kill closer to 40% of the bake time. To achieve this, the front zones of the oven have to operate at a higher heat, stopping gas production by killing the yeast earlier on in the bake. By making sure that you adhere to your usual yeast kill percent, you will gain better control of your product quality.
- Pyler, E. J. “Dough Fermentation.” Baking Science & Technology. Merriam, Kan.: Sosland Pub., 1988. P632.
- Pyler, E. J. “The Baking Process.” Baking Science & Technology. Merriam, Kan.: Sosland Pub., 1988. P74