Where were the photos taken? Which volcano?
Kilauea on Hawaii Island
That's absolutely NUTS. And also awesome. You know how some people do hot rocks brewing? You should try lava brewing.
I do know about steinbiers. Never really been tempted to try it though. The lava here is vesicular basalt (an extrusive igneous) which is very porous and brittle. Seems like I remember Chuck Skypeck experimenting with steinbiers and figuring out that a more dense intrusive igneous rock, granite, works best when you want to rock-n-brew.