Barrel Saunas
If you’ve ever tossed water on sauna rocks, you know it does more than make a satisfying sizzle.
That steam isn’t just for show—it’s the key to an authentic sauna experience! But not all rocks (or saunas) work well with water.
In this post, we’ll dive into the science behind steam in saunas, what makes certain rocks safe, and why random stones from your backyard aren’t a great idea.
Steam Saunas vs. Infrared Saunas: The Importance of Rocks
Steam saunas, also known as traditional saunas, rely on heated rocks to generate warmth and humidity. When you pour water on these hot rocks, it instantly vaporizes, creating a burst of steam known as löyly.
This steam temporarily raises humidity, making the heat feel warmer on your skin and enhancing the overall sauna experience. Infrared saunas, however, work differently. They use infrared heaters to warm your body directly, so no rocks or steam are involved.
In short, the steam in a traditional sauna adds a unique layer of relaxation. This combination of heat and moisture makes it quite different from infrared saunas.
However, if you’re after that authentic, steamy experience, you’ll want to avoid infrared setups—they just don’t give you the same atmosphere.
Why Not All Rocks Are Safe for Saunas
Not all rocks make the cut for sauna duty. Ideally, sauna rocks should be dense, non-porous, and heat-resistant. The reason? Porous rocks, like lava stones, may look great but don’t hold heat well. They might even crack under pressure, releasing that steam far too quickly for comfort.
And the worst part?
Porous rocks don’t keep the sauna warm for long. They lose heat faster than dense rocks, like granite, which maintain the ideal temperature for a relaxing session.
Choosing the wrong type of rock isn’t just a hassle; it’s a safety risk. Some stones contain natural minerals that release toxic fumes when heated.
While collecting rocks on a hike might seem like a fun DIY project, it could lead to some serious respiratory issues if those rocks contain harmful materials. Stick with rocks that are proven safe for sauna use.
Hydrofracturing: Why Cracks Matter in Sauna Rocks
Hydrofracturing might sound like something from a geology textbook, but in saunas, it’s a real concern. This term describes what happens when water seeps into tiny cracks in the rock and instantly vaporizes.
The rapid expansion causes the rock to split—or in worst-case scenarios, to explode. This is why cracked rocks in saunas are a big no-no.
If you’ve ever had a rock burst in your sauna, it was likely due to hydrofracturing. Rocks with tiny cracks or crevices allow water to infiltrate, which then heats up and creates pressure within the rock.
A solid, crack-free rock is the safest option for your sauna. So, next time you consider grabbing a random stone for your sauna, give it a knock. If it shatters, it’s out.
Avoiding Toxins: Why Backyard Rocks Are a Bad Idea
It might seem convenient to gather rocks from your yard or a nearby trail, but natural rocks can contain toxins that aren’t safe when heated. Some rocks have minerals like sulfur, arsenic, or lead, which release hazardous gases when exposed to high heat.
To play it safe, choose rocks that are certified for sauna use. These rocks are specifically chosen to withstand the high temperatures of saunas without releasing harmful substances.
Randomly selected rocks might look harmless, but they can pose health risks if you don’t know their composition. Rocks that are specifically labeled for sauna use, like granite, have been tested for safety in high-heat environments, so you can enjoy your sauna without worrying about toxic fumes.
Plus random rocks in your driveway can ruin your sauna. Sulfur being heated constantly can leave harmful residue inside of your sauna. We don’t like that and you won’t like it either.
How Sauna Rocks Work: The Role of Thermal Mass
In traditional saunas, thermal mass—the ability to retain heat—is essential. This is why granite rocks are commonly chosen.
Unlike lighter, porous rocks, granite holds onto heat, releasing it gradually over time. When you pour water on these rocks, the heat causes the water to evaporate instantly, creating that soothing steam.
Porous stones like lava rocks, however, don’t hold heat well. They cool down quickly, leading to inconsistent sauna temperatures and shorter sessions.
For a truly relaxing experience, stick with dense, high-thermal-mass stones that release heat consistently.
The Perfect Pairing for Our Scandia Stoves
Click Above to Check Out Sauna Stones the we have available.
Here’s a Great Article from the Sauna Times about Sauna Rocks
Here’s UFC Fighter Brent Primus putting our sauna rocks to use in one of our barrel saunas.