They're both "martini glasses" to most people. But they're not the same. At all. Here's what's actually going on.
The Martini Glass — tall, V-shaped, narrow rim. This thing is engineered. The narrow rim sends the drink straight to the tip of your tongue, where you taste sweet first. So that gin burn? Feels softer than it actually is. The shape also traps the aromas—juniper, herbs, all of it—and hits you with them all at once.
There's research on this. Same drink in a martini glass vs a coupe? People say the martini glass version tastes 15% sweeter and less boozy. The glass is literally tricking your brain.
The Coupe — shallow, wide bowl. Here the aromas spread out. You don't get hit all at once. You get layers. That weird herbal thing in the vermouth? The oak from a aged gin? Shows up better in a coupe.
Downside: wider bowl means ice melts faster. Like 20% faster. Drink it quick or it gets watery.
The Coupe — everyone says it was molded after some French queen's breast. Marie Antoinette. Probably not true, but the story stuck. Actually it was just a champagne glass in 1800s Europe. Ended up in American speakeasies during Prohibition. Shallow bowl meant less spillage if you had to run from a raid.
The Martini Glass — this one's Hollywood. 1940s. James Bond, Humphrey Bogart, all that. Became the martini glass in movies. The coupe faded out until the 2010s when cocktail nerds brought it back.
Depends what you ordered.
Dry martini, fancy gin, want to actually taste the vermouth? You'll probably get a coupe. That's the sipper's choice.
Fruity martini, something sweet, something that looks good in photos? Martini glass. The V-shape makes the colors pop and plays up the sweetness.
Wedding, gala, formal thing? Martini glass. The sharp lines just look right.
Same drink. Different glass. Different experience.
The martini glass makes it taste sweeter, smoother, more Hollywood. The coupe lets you actually pick apart what you're drinking.
Neither is wrong. Just depends what you're after.