For most of the 19th century, the caves on the Miller Brewery campus represented the height of technology in fermentation and storage of beer.
And you can still see evidence of the massive operation today.
Construction began on the network of interlocking man-made tunnels in the 1850s, and they were central to the brewery's production until the turn-of-the-century. After the beer was finished brewing, it was stored inside the caves where a crude measure of refrigeration was used.
Instead of refrigerators (they hadn't been invented yet), workers cut blocks of ice from area lakes and rivers and lined the cave walls with it, allowing the area to be kept an a constant, cool temperature.
But when large scale refrigeration was invented in the early 1900s, the caves were no longer needed and closed. Some were even sealed off. And they stayed that way for decades.
Today, parts of the caves have been restored and opened to the public as a stop on the popular Miller Brewery tour.
Check out photos from the caves below, and click the podcast player to hear OnMilwaukee's Bobby Tanzilo and I chat about his recent visit.
