It’s an age-old tradition in the UK for men of a certain age to fill the garden shed with bubbling demijohns, with the ultimate intent of disappearing into said shed with a select group of acquaintances for several days as a respite from 'er indoors.
I count maybe 10 carboys in the picture; 5 bottles of wine in each. So, enough for one drinking session for 20 sewage workers.
Nobody would make 370L of wine in carboys because 90 carboys would be expensive. You’d use a couple of those blue industrial drums or something. Just on the offchance officer Wiggum there hasn’t confused liters with gallons, though, a seizure of 500 bottles of illegal wine doesn’t seem like “one of the biggest operations we’ve seen in our county and possibly our state”. But I guess it made him feel important.