A traditional Finnish sauna that uses sauna rocks in its operation is often referred to as a rock sauna, and the name aptly indicates how important a feature of the conventional sauna is that the rocks are. The sauna heater holds and heats the stones, and the sauna bather throws water on the hot stones to create steam or loyly that increases humidity in the sauna room. Even in the modern era of far infrared sauna therapy, many sauna enthusiasts refuse to be carried away by the belief that sauna stones are essential to achieving the ultimate sauna experience.
While sauna fans are free to forever debate what defines an authentic sauna bath, it is an absolute must that rock sauna owners always use proper sauna rocks in their saunas. Many manufacturers and distributors often supply the Finnish style saunas and kits they sell, but sauna owners who enjoy frequent baths in their rock saunas will probably one day have to replace old stones with new ones.
Under intense pressure from fluctuating sauna temperature and humidity levels, even the best sauna rocks eventually crack and crumble. Once a sauna rock starts to disintegrate like this, it can’t retain heat as well as it used to. It will also produce less steam and can even clog your sauna heater. Before the day comes when you have to replace your sauna rocks, it is imperative that you learn how to tell the difference between the good sauna rocks and the bad ones.
For obvious reasons, sauna owners should avoid using rocks that can explode in the sauna, as well as those that emit poisonous or offensive odors. Neither should rocks containing sulfur minerals (yellowish minerals and / or metallic luster) or asbestos minerals be used. Rocks with sulfur minerals do not pose a health risk; they just wear out very quickly. However, rocks with asbestos minerals present a legitimate risk, as asbestos has been shown to cause cancer.
To avoid placing potentially explosive rocks in your heater, follow the advice of expert Mikkel Aaland, who recommends a simple test: “Heat a sample thoroughly for two hours or more. Drop it into a bucket of cold water and then look for cracks. rock is cold, test it by hitting it with a hammer or another rock. If the rock cracks or makes a soft squeaking sound when rubbed against another rock, discard it. If it survives, you have a safe sauna rock. “
Because the best rocks are the least exposed to the elements, certain quarried rocks are highly prized by lovers of the traditional Finnish sauna. One of the most popular is peridotite, a mined Finnish rock and one of the most common rocks in the earth’s upper mantle. Peridotite is a type of igneous rock, like olivine and vulcanite, which also work well in saunas. Many purists prefer to use dark colored igneous rocks because these rocks contain magnesium and iron and therefore have a relatively high heat capacity.
Be sure to consult the manuals and other literature that came with your unit and heater before replacing your sauna stones. Inadvertently, you could void your range’s warranty if you use a type of stone that is not specifically approved or recommended by the heater manufacturer.
The information packaged with your heater should also indicate the amount or weight of rocks recommended for use with the heater. However, as a general rule of thumb, you should use enough rocks to cover the heating elements of an electric heater. If you heat your sauna with a wood stove, the rocks should form a small mound that rises above the edge of the stove. In both cases, remember to pack the rocks loosely to allow sufficient air circulation.
Substantial information on sauna rocks can be found online, but not all of it is accurate or reliable. For example, one website recommends using smooth river and shore stones as sauna stones, while another advises homeowners to stay away from them. There is also disagreement about the suitability of high iron rocks for use in saunas. Questions about the ideal size, shape, texture, and mineral content of your sauna rocks may be best answered by the manufacturer or dealer from whom you purchased your sauna heater.