Chippewa Falls has a nice brewery cave in their local park. It was the first such cave I studied and since then I have learned quite a lot on this subject. Recently I went back for another look.
My first post on Chippewa Falls is here.
Here is the entrance to the cave.
The initial user of the cave was a man named F.X. Schmidmeyer. I have done quite a bit of research on this fellow, a three part series that starts HERE. In short, Schmidmeyer started the first brewery in town in the mid to late 1850s and purchased the land you see here in 1871. His earlier storage cave appears to have been obliterated.
Schmidmeyer did not have to start from scratch when digging his new cave, there was an existing niche or cave to expand. Not far away we see another example:
Layers of stone tend to be put down in specific strata, and caves are often located where water erosion has exposed softer stone under a harder layer.
Schmidmeyer used the cave for something just under a decade. The business faltered in the late 1870s and was sold at auction in 1881. His main competitor the Leinenkugel Brewery was right up the street from this cave site and appear to have taken it over. How long they used it is not certain, but most breweries of any consequence got mechanical refrigeration systems starting in the mid 1880s. And as this would have been a somewhat inconvenient overflow storage from their own caves I suspect it was not used continuously.
In 1906 this cave and the land it was on became part of Irvine Park, named after the local businessman who donated much of it. The cave was near the bear den which was the first part of the Irvine Park zoo, established in 1909. Local lore aside I can't find evidence that bears were ever lodged in this cave. In fact they would be able to hide out in the back and be invisible, which would hardly please visitors. Also there is a continuous flow of water in the cave from a natural spring. Great for cooling beer. Likely to make your bears soggy and unhealthy. No, I think the cave has always been just a local curiosity.
The cement pad you can see leading into the cave is a bit of a puzzle. I suppose it could be a loading platform for wagons to unload kegs, but the cave proper is too low for them to enter. And the pad only goes about 1/3 of the way back. beyond there it is rough, damp rocks. I was hoping to see the remains of bars, representing a bear enclosure, but the cement is entirely smooth.
And, the cement is in several layers. As you can see below this has been revised several times, the most recent date being far too new for a bear enclosure (the bear pens are next door, and while empty now are certainly many decades old).
There is even a layer of old metal in there.
Here we have documentation of the most recent cement work.
So, while you can't entirely discount other theories, I think the evidence here supports the cement pad being nothing more than a safe footing area for park visitors. Back when this end of the park was more visited this would have been a nice shelter for a picnic, or a retreat from bad weather.
The sign board outside the cave claims that the hole in the ceiling was to lower down kegs of beer. I think this is unlikely.
I have seen too many vent holes in brewery caves to consider this to be anything else. There are no remains up above of any platform or structure. And while I have had the opportunity to go over Schmidmeyers actual inventory and know that he was using some small 1/8 barrel kegs, the standard sized barrels would never fit down a hole this size. And really, why bother with all that when you have a nice road leading up to the cave entrance?
Of the other reported features of the cave I could find nothing. In particular I hunted for evidence of the iron gate that supposedly closed off the entrance from unauthorized withdrawals. But I could see no anchoring points in the walls or roof, and anything down on the floor is covered under layers of cement.