Sourdough in the microwave oven!
Generally it is recommended to let a sourdough starter develop in a warm place, with temperature slightly above room temperature. Our place is heated through air vents (we don’t have radiators) and the refrigerator/freezer is rather energy-efficient (it doesn’t emit much heat) so it has been a challenge to find a warm spot in our kitchen. One thing that occurred to me recently is to use the radiant heat from the light bulb in our microwave oven. It lights up when the oven door is opened. The temperature in our kitchen is currently 21-22 degrees C, while in the microwave oven (with the door almost shut) the temperature reaches 28 degrees C.
I’ve been experimenting putting my sourdough starters in the microwave oven at this high temperature, and my doughs have definitely responded with more activity, however, perhaps too much so. Particularly my wheat sourdough became very thin (almost runny) overnight in the microwave oven. Probably it became so acidic that the gluten broke down.
The videos below show a freshly fed wheat sourdough (labelled “New”) and a the same sourdough after 16 hours at 28 degrees C (“Old”). While the fresh sourdough is thick and sticky, the fermented sourdough is quite runny, like sour milk or thin pancake batter.
So after these experiments I’ve actually gone back to develop my starters at room temperature, but the microwave oven trick may become useful as the winter draws in and cools down our place a degree or two.