A lot of what you think you know about wine may actually be a myth, and that includes the purpose of the dent in the bottom of a bottle. While it served an important function centuries ago, the design feature today is cosmetic at best—and deceitful at worst.

According to Wine Spectator, the dimple in the bottom of your wine bottle is actually called a “punt.” Prior to the Industrial Revolution, all wine bottles were handmade by glassblowers, and these punts were added to ensure they could stand upright. Today, most wine bottles are made by machines, and it would be easier to manufacture them with even bottoms that lay flat than it was 200 years ago. But because of tradition, the punt has endured.

The wine industry has found alternate uses for the archaic dent over the years. It creates a natural place to hold a wine bottle, and according to some experts, when pouring a glass, the proper technique is to rest your thumb in the bottle’s indent. (Others say holding the base of the bottle is also OK, so long as your hand doesn’t creep up more than halfway.)

The punt can also be exploited to trick customers into thinking they’re getting more than what they paid for. Two wine bottles stored next to each other on a shelf may appear to be the same size, but if one has a deeper dent, it actually contains less liquid.

The depth of a bottle’s punt also used to be a marker of value, and some wine manufacturers continue to exaggerate the indents at the bottom of the glass to pass it off as high-quality. But as is the case with the heft or the color of your wine bottle, these cosmetic features have nothing to do with the caliber of the product inside.

Those aren’t the only reasons that have been floated for the continuing presence of the punt: According to VinePair, some claim the feature keeps sediment from being incorporated back into wine as it’s poured, or that the punt increases surface area, which in turn allows the wine inside to chill more quickly. Others say punts make wine bottles easier to clean before the wine is inserted, or that they allow the bottles to withstand higher pressure, or even that they’re an organizational feature—apparently, “Punts allow for more ease when it comes to stacking wine.”

The wine world feels a lot less intimidating when you realize a lot of its conventions are meaningless, like the rules that reds must be served with meat or that corks are better than twist caps. Here are some more wine myths to look out for.

A version of this story ran in 2020; it has been updated for 2023.

This article was originally published on www.mentalfloss.com as The Reason Wine Bottles Have Dents in the Bottom.