In our quest of exploring different maturation vessels in making sour beers, we decided to obtain granite tanks.
We thought that due to granite’s complex mineral structure of feldspar, quartz, mica and amphibole and its porosity it should have the ability to dramatically transform the flavors and aromas of a complex brew.
After filling the granite with beer, we also saw a pulsating re-fermentation triggered by wild airborne yeast and yeast hidden inside the granite rock. This process seemed to be helped by the porosity of the igneous rock.
Our granite tanks were custom made in Austria. One is made from Spanish Rose Granite and the other is Bavarian Blue-Grey Granite. We have learned that both impart different aspects to our beers.
To drink beers from this project, look for beers that were matured in granite. Any our beers could make it into the granite fermenters for a special release.