If you think you're supporting a winery by picking out one of their bottles, you're going to be shocked when you find out just how much they actually get from your purchase.
Let's take a bottle that costs between $28 and $30. Once you factor in the distributor's cut, how much the retailer takes, and production costs, the profit that the winery gets is, on average, somewhere around a single dollar.
Exact numbers are tough to come by, because most wineries are private companies and don't divulge their numbers. Some do go public with their numbers, though, and it's hugely valuable for the consumer to know not just why they're paying a particular price, but why it's so, so important to buy directly from a winery. When you do, you skip the retailer and the distributor, and the wineries get a lot more return on their product.
In 2014, Napa Valley's Chateau Montelena gave out some numbers, and said that for every $100 bottle of wine sold at a retailer, they got $19. It's not unique to retail stores, either. Say you get a bottle of wine at a restaurant, and you tip your waiter 10 percent of the price of that bottle. You're giving that waiter an average of five times what you're giving the winery, and that's why wineries put so much into their tasting rooms and on-site shops.