Back when they first started making beer there, they hired some local miners to dig into the hill behind the brewery. It is solid rock, and they dug it all out by hand. It stays nice and cool down there and is perfect to age the beer. When Prohibition hit, the feds came along and destroyed all the beer barrels, except one, and they walled off the tunnels.
They made ice cream during that time to stay open. No refrigeration needed, and they had enough tunnels to store all the beer they produced. The tour guide shows us one door that was the "government room" and only the feds had keys. It was to measure the production for taxation. They pay the feds 18 bucks per barrel, and the state gets 2 bucks.