There are several ways to prevent those inevitable wine bottle drips from staining your tablecloth. You can wrap the bottle in a napkin while you pour, just skip the wine glass altogether and drink straight from the bottle, or use your physics degrees to re-engineer the bottle’s spout so it never drips again.
As a wine aficionado, Brandeis University biophysicist Daniel Perlman has almost certainly tried all of the above, but he’s had the most success with that last approach. Over the course of three years, through some of the most enjoyable research he’s probably ever conducted, Perlman studied the flow of liquid as it leaves the lip of a wine bottle.
Slow-motion video revealed that a stream of wine, or really any liquid poured from a bottle, has the tendency to curl back over the lip and then run down the side due to the bottle being made of glass which is hydrophilic—it attracts water-based liquids.
There are contraptions on the market you can attach to a wine bottle to counteract this effect, but Perlman wanted to solve the problem, at its source, once and for all. After a bit of trial and error, he found that using a diamond cutting tool to carve a two-millimeter-wide, one-millimeter deep groove just below the lip of a wine bottle was the simplest solution.
When wine droplets trying to run back down the bottle encounter that groove, they would need to flow against the force of gravity to go up and across to the other side, or simply leap over it. What happens instead, is that those potential dribbles just return to the rest of the flow, saving napkins, tablecloths, and shirt sleeves from getting strained.
There’s no word on when Perlman’s improved bottle design will be adopted by bottle makers or wineries, but adding that simple additional groove will require modifications to glass molds, so there will be some additional costs up front. But the benefit to the consumer would be immeasurable, and could end up being a valuable marketing tool until every winemaker jumps on the drip-free bandwagon.