When you think of a library, you undoubtedly envision books. But did you know that a library can also refer to a wine collection?

In theory, a “library wine” is any unopened wine that is stored in a cellar, wine fridge, closet, or other repository. By this definition, most of us have at least a small wine library (absolutely no judgment if you lack restraint in this department!).

In practice, a library wine is one that can be cellared for many years because it is inherently capable of aging. Such wines are sourced from high-quality fruit. They can be red or white, but they must have adequate levels of either sugar, tannins and/or acid—all of which serve as natural preservatives—to support aging.

Many wineries will reserve a portion of each year’s vintage for their libraries. Napa Valley’s Freemark Abbey is a pioneer in this area. In the 1960s, it began setting aside wines for what is now an incredibly extensive library that dates back five decades – a testament to the quality and age-ability of its wines. The estate’s Library Tasting is a chance to travel back in time. You get to sample Cabernet Sauvignon wines that are up to 25-years old and compare them with the newly released vintages to taste how wine ages over time.

What exactly happens to wine as it ages? It might be counterintuitive, but red wine turns lighter in color—going from deep purple to light brick red—while white wine grows darker, eventually transforming into a golden, brown hue.

As wine ages, it develops what are called tertiary aromas and flavors. These are the notes that develop during the maturation or aging phase, long after harvest (the primary notes) and fermentation (the secondary notes). Aged wines taste leaner, less fruity and more savory.

Older red wines might have aromas of baking spices, cedar, cigar box, smoke, dried tobacco or dried leaves. Older white wines tend to show toasty notes and flavors of aged cheese, cream, brioche, nuts, or oak. And don’t worry if you find some sediment or tartaric crystals in an older wine. These won’t hurt you, but it is more pleasant to filter them out before drinking.

With all the exciting new vintages available, why buy a library wine? For starters, these wines have been perfectly aged for you and and are released to you when they are at their optimal point for drinking. A library wine can serve as a trip down memory lane or make a special gift for a milestone birthday, graduation or anniversary.

Library wines are also a great way to expand your tasting skills. These wines have been aging and evolving without oxygen. Let the genie out of the bottle (so to speak) and taste how they differ from young wines. Library wines become more compelling through the years by layering new aromas and flavors that enhance their complexity. Enjoy a bottle through the course of an evening and experience how the layers unfold in the glass.

When it’s time to open the bottle (may we suggest Open that Bottle Night?), let it stand for a while to ensure that any sediment falls to the bottom. Next, use a special corkscrew such as an Ah-So, which has prongs for extracting the cork by its sides, or The Durand, which combines Ah-So-like prongs with a normal corkscrew to pull the cork from both sides and center.

Slowly rock the corkscrew laterally back and forth, adjusting pressure as needed, then gently twist and pull. If the cork breaks in half, you can insert a regular corkscrew at a 45-degree angle into the remaining piece and slowly extract. If all else fails, use the handle end of a spoon to gently push cork into the bottle, then filter the wine through cheesecloth or a tight-weave mesh directly into your glass.

After opening the bottle, you only need to decant the wine for about 15-20 minutes as older wines need much less aeration. Be prepared for a totally different taste than you have with a younger wine. While older wines taste leaner and less fruity, they often have an ethereal quality to them. For this reason, they pair beautifully with rich foods, such as this Artisan Cheese Board with Bacon, Almonds & Orange Marmalade.