While its true that alcohol does not at all help you out in the cold (it just makes you feel warmer by widening your blood vessels, so more blood flows to your extremities which are the parts that most feel cold, but that runs counter to the purpose because it means you just lose body heat faster... whatever)
But Vintage Story is foremost a game, and replanting berry bushes or some future olive trees or what have you to make fruit juice and wine or brandy is a system you can engage with for many hours, and the reward (alcohol), which lasts a long time but at lower satiety (and even worse compared to meals.)
Recurrants are 80 satiety per berry, or 1280 satiety for 16 berries -> five litres of juice (1000 sat) -> (400 as wine) -> (40 as brandy). If you're in a situation where you're making wine to extend the shelf life of your food, then that kind of implies you already have more than enough food to live off. If you're at the stage where you can even consider brandy, you're way past the point where you have to preserve it for shelf stability due to worries of running out of food, and you'd be doing it only because you already have so much food you cant even drink your wine fast enough (and remember, wine is already almost an 80% satiety loss compared to meals made with the same fruits) and you're just trying to keep it from spoiling.
So the system ends up not really serving a purpose, I feel, because while it's something to do, you don't get any useful product out the end. The fact that alcohol in reality is pretty useless is kind of irrelevant, I think, because it shouldn't matter to a game.
I dont claim to have the answer, but I feel for how involved brandy-making is, it should have some upside. I doubt anyone's actually drinking the brandy they end up making anyway.
But, as one idea, maybe drinking at least one liter of alcohol would improve the duration of the improved satiety you get from eating a meal?