The "wino" on the right is a carboy of apple wine that has been fermenting for months. After success in making a gallon of apple wine (using fresh pre-pressed cider) I dove in big time and got 30lbs of fresh apples, washed and cut them up, and then mixed it all with fresh water, acid blend, and sugar in a 7 gallon plastic primary fermenter.
It wasn't pretty.
Heck, it wasn't even enjoyable. Apple juice was dripping and oozing everywhere while the fermentation bubbled along at a less than stellar clip. The apple mass swelled and pushed up against the lid unless stirred three or four times a day, a process that only added to the dispersing of juice throughout the house.
After over a week of this the juice was siphoned off into a carboy and I was faced with the task of trying to press the remaining juice out of three gallons of apple chunks and slush. Mistake #1: putting some of it through a juicer resulting in an unstrainable goo. Mistake #2: didn't throw the goo away, added it to carboy. Mistake #3: I didn't give up and bottle it as slightly fermented apple cider.
The "goo" settled into various layers of apple strata in the carboy, miraculously (with the help of trapped CO2 from fermentation) defying gravity and rising to the top, pushing it's way into the fermentation lock. Mistake #4: pulled off fermentation lock in order to try and siphon off excess goo.
To it's credit the lock was doing it's best to keep things under control, which was discovered when it was removed and the highly pressurized goo came shooting out to coat everything within a three mile radius. A couple more weeks of goo battles ended in another racking (and filtering) with the goo content reduced and the stuck fermentation restarted.
The jacket helps to keep the wine insulated and warm enough for the fermentation to proceed at it's leisurely pace. Furthermore, since the wine has taken on a bit of a personality it is only fitting that we aid in it's anthropomorphic progression.