In the spring the birch takes water, releases its reserves and moves them into the eyes that have slept during the winter. These, on standby, will be awakened by feeling the thrust of sweat and bursting with open scales, where the leaves will appear by igniting a new hatch and putting on a tree. When the leaves are widened into sunlight, the raw sweat that comes from the bottom to the top is transformed, and in an elaborate sweat, it is sent from the top down, so that all the eye, branch, trunk, roots, tree can be thrown to the surface.

We don't have a habit here, but to the north, where birch is more abundant than here, you want to pick up that first spring sweat. It's sweet; then, when the tree foliage starts working, sweat cracks.

In the freshly milled, sweat is diaphanous, pure, and a little sweet gives it the softness of silk. To celebrate the entrance in spring, the new year is used as an aid to start with a special cleaning, both inside and outside: drinks, food supplements, skin and hair cleaning of the face... Birch has also been called “the tree of the diseased kidneys”. Once outside the tree, because of its sugar, it will begin to boil, like the must of any fruit. Boiling becomes an alcoholic beverage. They also cook, forming a thick jaropa.

In cold countries, where winter seems unfinished, the passage of sweat through birch is considered a miracle, a sign of spring coming. They call it the "tree of wisdom."