How Long Is Opened Bourbon Good For?

Bourbon is a spirit that's meant to be savored. Whether it's a less expensive bourbon worth buying, such as Four Roses Kentucky straight bourbon, or something pricier, you may find yourself taking some time to get through an open bottle. And, if you're like us, you may have wondered if that bottle could go bad. So, we asked Robyn Smith, a whiskey expert and owner of the blog NEAT (@thisblogsneat on Instagram), to help provide some answers. "If it's sealed tightly and kept out of heat and sunlight, it'll hold up for many years," she told Chowhound in an exclusive Q&A. "Bourbon is high-proof and shelf-stable."

That's the good news. But if you're drinking a bottle of something extra special at a very leisurely pace like Eagle Rare 17, the very pricey limited-release bourbon, you might run into issues once you reach the halfway mark. Smith says you may begin to see signs of oxidation, which can include irreversible cloudiness and off-flavors. There could be a hint of sourness, or the spirit's original flavors and aromas may become toned down. Thankfully, there are some preventive measures you can take before oxidation sets in.

Bourbon is at least 40% alcohol by volume, which keeps bacteria from forming, but there are other culprits that can wreak havoc on the spirit once it's opened. Among these worrisome conditions is exposure to high temperatures, direct light, or too much oxygen, according to Robyn Smith. "That said, if the bourbon has been stored properly, this is rarely a concern," she says. "And even if some cloudiness or flavor drift does occur, it won't make you sick."

Smith suggests keeping any opened bottles of bourbon in a cool place out of direct light and making sure they're sealed tightly. "If the bottle's running low and you're not quite ready to polish it off, consider transferring it to a smaller glass container to reduce headspace and slow down oxidation," she says. So if you happen to have a bottle of 25-year-old Pappy Van Winkle, the most expensive bourbon in the world at $50,000, and you don't want to knock it back, take Smith's advice to heart.