Beginning as the Minneapolis Brewery in 1866, the Heinrich Brewery, as it came to be known, existed until 1903. The area was dubbed “Brewery Flats” because the Noerenberg Brewery (whose lagering caves are utterly inaccessible today) was also located nearby. These breweries, along with others, merged to form Grain Belt Beer in the 1890s, which went on to become a nationally recognized brand.
Heinrich Cave was dug in the sandstone, probably in the 1880s, pretty much at river level, with more than 1,000 feet of passages. The three entrances (two of which are completely blocked up, while the middle one is gated) led to three passages going straight into the bluff, these being connected by low crawlways. In the late 1930s, when the sanitary interceptor tunnel was being dug just inland from the cave, the latter was used as a dumping ground for excavated sand—which is why the passages, originally 20 feet high, are nearly full to the ceiling throughout much of the cave.
Heinrich Cave was gated as a bat hibernaculum for the Eastern Pipistrelle by the DNR in 1990, and is no longer open to the public. When we initially explored the cave back in the 1980s, before the gate was installed, we found improvised fortifications, toy swords, and so forth, indicating the cave’s use by university students for games of “Dungeons & Dragons.” We also came face to face with two healthy, fat raccoons. In later years, when I noticed that the DNR wasn’t paying very close attention to the hibernaculum (the lock had been sawed off by vandals and not replaced), I installed my own lock on the cave, which, in turn, was sawed off.
Heinrich Cave is unusual for its mineral formations. The largest room in the cave, just inside the gate, is very wide and low, but there’s a breakdown pile here that has been fused into the form of an orange stalagmite by iron-rich waters dripping from the ceiling joints above. In the remotest part of the cave there’s the Red Room, chock full of reddish rusticles (rust stalactites). The floor here is corrugated with red flowstone, with nests of cave pearls. A greenish pool of water in the rear of the Red Room is afloat with calcite rafts.
The most unusual mineral found in Heinrich Cave, however, is gypsum, usually associated with drier and warmer caves much farther south. A small crawl tube at the rear of the cave is adorned with gypsum needles and gypsum petals can be found on the ceiling nearby. In other places, it appears as though gypsum has grown between layers in the limestone ceiling, wedging them apart and causing them to collapse onto the floor below. It appears that what the Minneapolis breweries lack in size and number, they make up for in their unique crystal deposits.
EXCERPTED FROM SUBTERRANEAN TWIN CITIES.