For those interested: 
#grownostr
Discussion
Okay this product is of high interest to me! I have a 30 yr old vine and have 4 bushels of concord grape to process every year. I use a stock pot and potatoe masher..
Do you just steam the grapes and the juice stains as it steams?
Yessir. That's exactly how it works. I'd guess we had a 75-80% volume reduction just from the steaming, no mashing or pressing at all until I squeezed the last tablespoon or so out of the leftover pulp. Started with roughly a gallon of grapes and ended with 3 quarts of juice.
Nice. Those work so good.