Is It Safe to Eat Guacamole That Has Turned Brown? Experts Weight In

Guacamole is one of my all-time favorite spreads: If I’m not dipping chips, french fries, or veggies into smashed avocados, it’ll be used as a condiment or topping for everything from toasts to burgers to baked potatoes. Heck, I even add it to my chicken salads, dressings, and deviled eggs!

When making (or opening) a fresh guac, there’s nothing worse than enjoying a few scoops and wrapping it up in the fridge, only to find it turned an unappetizing, tepid brown color the next day. Not only does this transformation look unappealing, but I actually worry if it’s safe to eat.

To find out whether my inclinations are true, I spoke with a food safety expert and food scientist to get all the need-to-know information on guacamole that has turned brown.

Why Do Avocados Turn Brown?

There’s actually a very scientific explanation for why leftover guacamole changes color. Sarah Alsing, MS, RD, registered dietitian, food safety expert, and recipe creator for Delightfully Fueled, explains it’s “due to oxidation, which means an enzyme in the flesh of avocados reacts with oxygen and turns brown.”

Referred to as enzymatic browning, this process happens when you slice into an avocado. The fruit (yes, avocado is a fruit!) has polyphenols—a naturally occurring, antioxidant-rich plant-based compound—that react with enzymes when exposed to the air. Once kept apart, when they mingle, “they can now have a heyday and turn brown,” adds Abbey Thiel, PhD, food scientist, consultant, and educator.

This same enzymatic reaction occurs with many other foods, too. “It’s just like how cut apples turn brown,” adds Alsing.

Can I Still Eat Brown Guacamole?

While the science is interesting, the real question remains: Is it safe to snack on guacamole after it undergoes this oxidative process? Absolutely, assures Alsing: “It may not look pretty, but brown guacamole is perfectly safe to eat.”

However, the flavor of brown guac may not be exactly the same as a fresh batch. “Brown guacamole may taste slightly bitter due to oxidation,” says Alsing. However, for most people, the difference won’t be too pronounced. “I think you have to be a pretty sensitive taster to notice,” Thiel adds. “The main issue is that we eat with our eyes and often judge food by its appearance.”

How to Prevent Guacamole from Turning Brown

Thankfully, there are plenty of ways to prevent guacamole from turning brown for several days. “This is classic chemistry,” explains Thiel. It all comes down to limiting how much oxygen can get to the avocados or controlling the enzyme.

“I squeeze lemon juice on top of guacamole before storing it in an airtight container in the fridge,” Alsing offers, noting that citric acid (in lemons and limes) delays oxidation and helps keep guacamole green longer.

Some folks swear by sticking the avocado pit in a freshly made batch to prevent it from turning brown, while others claim this isn’t true. Alsing says placing a piece of plastic wrap directly on the top of the guacamole and then covering it with an airtight lid helps limit oxygen exposure. Adds Thiel: “Be sure to store leftovers in the fridge in a timely manner. The cold temperature will slow down the enzymatic reaction.”