Here’s a fun fact you may not know: not all wine is vegan. Some wine is clarified with “fining agents” that are made from animal products.
These fining agents help eliminate proteins, yeasts and other molecules that give wine a cloudy appearance. They can also eliminate harsh tannins, helping the wine taste smoother at a younger age, wine blog VinePair says. As The Kitchn explains, the fining agents attract molecules. By collecting around the fining agent, the molecules form larger particles that are then easier to filter out of the wine.
The amount of the fining agent left in the wine (or beer) might be minute, but some people are extremely sensitive to any amount.
Another wine production thing I was not aware of. I would expect this to be an issue for the large scale wine production outfits. It never came up when I was working for someone who was transitioning from accounting to wine making. My recollection was wine makers were interested in good grapes, and what you got in the bottle was it for that year. It depends, but a lot do not grow all the grapes themselves. They’ll have some of their own, but source a fair bit from local wine grape growers.
The article mentions the wine bottle label. I don’t know what or if anything changed since I last looked into it, but there was no standardization whatsoever as I knew. I get the impression that hasn’t changed.