So here’s how we started. The wort had been done the day before and because of time constraints had been left overnight. The next day it was, pardon the pun, stone cold. So I got the rocks I was going to use and started heating them.
This is my first of many rocks being used in the mix. We built a good sized fire and placed them in amongst the coals. The first three or four rocks brought the temperature from 60 to a nice simmer of about 170 degrees. The process took a bit longer than anticipated.
Because I had several size rocks I’ve come to the conclusion that if you’re going to do this process you need to start with a couple of large rocks at first. Then to maintain temp over time you would use smaller rocks that just maintain the heat.
After several more rocks we finally got some response:
The rocks heat also carmelizes the sugars and between the smokiness and the carmelization, you can probably expect a strong beer with a very robust body. The rocks turn black when the carmelization starts on the outside.
It’s important to use rocks that are harder and as non-porous as possible. Sandstone or quarts are bad choices but this rock here was (I believe) a piece of basalt. My stones were all ocean stones which have been on my woodstove for several years so all the moisture was drive out long ago. It also makes for easier handling. The side effects of a hot rock dropped into cool or cooler liquid can be explosive and fortunately we didn’t have any catastrophic results. Although we did have some overworked rocks.
You can see the video at: http://s46.photobucket.com/user/KytheSz/media/DSCF2017.mp4.html