Indirect heat transfer through a liquid. The definition, very simplified, and the operation of the bain-marie is well known by anyone who has ever cooked. But when was the last time you used it or saw it in one of those kitchens seen in a restaurant? Although, indeed, this technique, whose history goes back many centuries, seems somewhat out of use, pastry chefs and chefs confirm that it is still essential in some recipes.

Did the microwave finish with the bain-marie? In lower case, by the way, according to the RAE. Melting chocolate without burning it is one of the best-known uses of this system, but with small touches in the microwave, stirring, and a little care, the same thing can be achieved without the need to use fire, a pot, water, and a bowl.

“It is a classic for working chocolate without a microwave or gadgets. You heat in a bain-marie and you can melt, but you can also temper it to shape and decorate”, explains Ximena Pastor, one of the managers of the L’Atelier Barcelona pastry shop.

But it is true, he points out, that many workshops use devices such as the Magic Temper that maintains the cocoa butter at a certain temperature and viscosity and, when added to the melted chocolate, tempers it just by mixing.

If even relatively modern recipes or techniques are difficult to trace back to the exact moment of their invention, in the case of the bain-marie, centuries have further blurred the origin of this technique.

The most widespread version is that we owe this system and its name to ‘María la Judía’, considered the first female alchemist and who lived between the 1st and 3rd centuries, depending on the sources consulted.

There are no writings of this scientist, also known as María the Hebrew or Míriam the Prophetess, but there are later references that mention her as a scholar of her time and a pioneer in techniques such as this hot water bath.

Stories or legends aside, what is known is that the bain-marie was originally a system linked to the world of chemistry and microbiology. In fact, it continues to be a key element in laboratories for, as indicated in the catalog of a material supplier, for serological tests and incubation and agglutination processes, among others.

The jump to the kitchens occurs, in fact, with an idea closer to a laboratory than to a recipe book: the conservation and sterilization of food. You have to jump to the 18th century for the Frenchman Nicolas Appert to discover that by placing food in a container, closing it and heating it in the bain marie, it lasted much longer without going bad.

Very useful in military campaigns and at sea, that discovery of hermetic preservation was the first step towards sterilization. Something, by the way, still widely used in home canning, as anyone who has bottled at home will know.

But returning to the L’Atelier workshop, Pastor reminds us that the bain-marie has great advantages when working with delicate ingredients. Thanks to this technique -he explains- “direct heat that can burn or cook preparations that we are only interested in heating or working at low temperatures is avoided.” In addition to chocolate, another example would be cooked meringues. Furthermore, in this case there is no machine that can replace the traditional one, he says.

Low temperature cooking could be considered a close first to the water bath. More specifically, the sous-vide method that consists of vacuum-packing food and immersing it in water at a controlled temperature for a certain time. It is not exactly a bain-marie, but the similarities in the indirect heat transition system are evident.

Thinking about this technique inevitably leads us to the Roca brothers. And precisely the oldest of them, Joan Roca, shared some advice in Comer a long time ago so that scrambled eggs turn out creamy and perfect: cook them in a bain-marie instead of in a pan directly on the fire.

Something also applicable to many sauces in which eggs play a fundamental role. In fact, in Escoffier’s kitchen model, the saucier -cook dedicated to sauces- has a fixed position next to a large copper pot in which he prepares many of these sauces in a bain-marie.

Ximena Pastor gives us another good example: a classic Dutch recipe based on this technique: “the yolks are cooked in a bain-marie, beating and then when they foam and thicken, add the clarified butter and touch it up with the infusion or reduction of vinegar and wine, pepper”.

So almost two thousand years after that invention by a woman alchemist, it seems that the bain-marie still has a lot to say in modern kitchens.