Demystifying science | Ice or water for bread?

Every week, our journalist answers scientific questions from readers.

Boiling water, to get steam as quickly as possible, according to Christina Blais, who published the books Christina’s bread And The chemistry of desserts.

“We want to have steam during the first half of the cooking,” says M.^me Blais. So the ideal is to put boiling water in a metal container that is already in the hot oven. But since it steams immediately, some people use ice to avoid burns. You can also spray the bread before putting it in the oven, and add a few sprays in the oven when putting the bread in the oven. »

These tips apply to bread baked without protection in the oven.

For breads baked in a crucible or other closed container, the moisture present in the bread is normally sufficient, so no need to add water or ice.

Bruno Blais, specialist in fluid mechanics at Polytechnique Montréal, explains that putting ice in a hot oven slightly delays the increase in humidity in the oven, compared to hot water. “The ice will have to melt first, then it will be transformed into steam. It’s a question of thermodynamics. »

Mr. Blais works on other types of fluids. “I particularly study 3D printing by fusion of material powder. The powder becomes liquid then solidifies with 3D printing. »

Are there still things that are poorly understood about the melting of a solid and the vaporization of a liquid? “I would say there are more unknowns when it comes to the formation of ice from a liquid,” says Mr. Blais. It takes a crystal to start the formation of ice. Often it will come from impurities. But when you have a very pure liquid, for example distilled water, the liquid can remain liquid well below freezing temperature. »

To return to bread, humidity allows for a less hard crust and for bread to expand more, because the wet surface remains flexible, according to Christina Blais. “Ideally, we put the water in a cast iron pan because it retains heat better. Remove the container halfway through cooking, unless all the water has already evaporated. »

Avoid cooking with convection to prevent steam from escaping from the oven.

Convection ovens like gas ovens are ventilated and therefore steam is not retained as long as in an electric oven. And be careful, you should not pour the water directly into the bottom of the oven, “and especially not on the oven window,” says M.^me Blais.

Annie Ferland, from the Science et Fourchette website, thinks that putting an ice cube in bread cooking in a crucible can be useful to increase “heat stroke”. “But it is certain that with bread cooked without protection in the oven, you need water for at least 20 minutes at the beginning,” says M^me Ferland.

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