@selzero @kaia Rather than “bad grapes” it’s frequently a blend of leftovers. What used to be called 2 buck chuck (Trader Joe’s) was notorious for occasionally having extremely good wine, but with very high variation.
People would buy a bottle of it, sample it in the parking lot, and if it was good, they’d go back and buy as much as they could afford.
Don’t know if it’s true anymore. It’s certainly no longer 2 dollars a bottle.