I always forget about half bottles of wine. They’re like that former colleague who was kind of soft-spoken but stealthily smart and funny, and now every time you run into her you make a tentative coffee date, but then lose her card (again) in the depths of your bag.

Anyway, a long way of saying that wine half bottles can be great, but are easy to overlook. They’re usually placed in some obscure part of the wine store and don’t figure prominently on wine lists. (One happy exception in New York City: Landmarc makes a point to include lots of half bottles.) And selection can be limited, as often only bigger wineries put out half bottle sizes.

But they’re worth hunting down, for several reasons. Obviously, they’re a great choice for people who don’t drink a lot at one sitting. And half bottles let you try a pricier wine without fully committing. They also work well if you and your traditional drinking partner have different tastes. When we first started dating, Paul was not so much into the white wine, so occasionally I’d get a half-bottle of white for myself while he’d tuck into some red. (Yes, over the same meal. There are plenty of dishes that go just as well with a white as a red—but that’s a topic for another post.)

But maybe my favorite thing about half-bottles is that they age faster than standard-sized ones. Basically, wine ages through slow oxidation – oxygen entering the bottle through the porous cork. The opening of a half-bottle relative to the bottle’s total size is bigger than it is for a full bottle, which means more oxygen and the wine ages faster. (The corollary: big bottles age more slowly.) Because it can be hard and/or expensive to buy older wines, half-bottles give you a great opportunity to see what impact age has on wine.

I can’t stress how important it is for you to try older wines as you expand your wine vocab. As wine ages, it takes on all kind of aromas and flavors you rarely find in young ones: mushrooms, leather, hazelnuts, smoke…these may not sound incredibly appealing, but trust me when I tell you that they can be amazing. I’ve had more luck with finding good white half-bottles than red, particularly California Chardonnay and Burgundy. Pick up a few bottles (for Burgundy, the 2005 vintage was particularly great) and see if you can detect any of those flavors. If so, and if you fall in love with them, I apologize in advance for turning you on to this expensive habit through the gateway drug of the half-bottle. If you don’t like them, then, well, you dodged a bullet – and you have half-bottles to thank.