The stones

„The best stones are collected from the riverbed," my grand uncle once said to me. He was teaching the old way of gathering sauna stove stones. One would go out, wander around the riverbed and chose the stones that were warm, more so than others, from the effect of the sun.

Hard stones such as grantite are up to the job. The best stones are the size of a large fist. Brittle stones, like limestone, are no good. They will fracture with the constant heating and cooling. The best stones are hard and heavy rocks, that can store a significant amount of heat, while standing up to the constant heating and cooling effects.

The main job for the stones on top of the sauna stove, is to store heat and release it over an extended period of time. Usually more intensively when throwing water on top of them. In the typical Finnish sauna, stones can keep the sauna warm for a couple of hours, with no additional heating. In the smoke saunas of old, saunas could well be warm for several days due to the massive amount of stones used.

When throwing leil, many factors play a role in how it reaches the people who are waiting, full in anticipation. The surface area where water touches the stones, the texture of the stone surface, heat conductivity and the dissipation of the water you threw. The better the water dissipates over top and bottom rocks and covering a wider area, the longer longer the dash of heat and steam will be.