To get to the bottom of the problem, we tested five methods for how to keep avocado from turning brown to discover the most effective and practical solution to spare the fruit (and your money). From storing it in water to using lemon juice to keeping the pit in—just to name a few—read on to find which freshness trick was most effective.
Before we jump in, it’s important to note that every test we tried has one thing in common: they all attempt to prevent prolonged exposure to oxygen, which is an avocado’s worst enemy. The edible insides of the fruit contain an enzyme called polyphenol oxidase that browns when exposed to oxygen, similar to a cut apple. This reaction happens quickly; it tends to become noticeable after just three hours of exposure. Though you can still eat a slightly browned avocado, by the nine to 12-hour mark or sooner, your bright green guac will taste unpleasantly bitter and have turned a greyish-brown color.
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We tested it: How to keep avocado from turning brown
1. Keeping the pit inside of the avocado
Contrary to popular belief, keeping the pit of avocado inside while storing it does little to prevent browning. As mentioned before, oxygen plays the most significant role in darkening the fruit’s vibrant color. Though the pit might protect the area immediately surrounding it from coming into contact with the air, it won’t shield the rest of the exposed surface from changing color. Confirmed by our testing, we found that just after a few hours, the surface began to turn greyish-brown, ranking the “pit method” the worst of the ones tested.
2. Storing the cut avocado in water
As oxygen can quickly damage the surface of an exposed avocado, finding ways to create a barrier to prevent this from occurring can help prolong the freshness of the fruit. One way to do so involves using water to submerge the avocado to prevent air from touching the surface.
We tested it by taking a container large enough to fit a halved avocado (with the skin still on) and filling it with an inch and a half of cool water. Then, we placed the avocado open-side down directly into the water to prevent oxygen from reaching the exposed surface area, and stored it in the refrigerator uncovered for a few days.
Though the avocado did not absorb much of the water, the surface did become slightly mushy after getting submerged. That being said, the avocado maintained its coloring and browned minimally during the first day or two.
3. Tightly wrap the surface of the avocado with cling wrap
One of the most classic methods for how to keep avocado from turning brown involved tightly wrapping the exposed surface of the avocado with cling wrap to keep oxygen exposure to a minimum. The issue, however, was getting the cling wrap to perfectly stick to the surface without creating gaps or pockets of air. After a day and a half, the avocado began to brown in any exposed areas.
However, it is important to mention that this method proved successful for preserving guacamole for a longer time. When storing it, gently press the cling wrap down onto the surface of the mixture in a bowl or container to remove all of the air. This technique vastly helped prevent guac from browning for up to two days.
4. Store your avocado with a few slices of onion
A slightly unconventional approach compared to the other methods, storing the avocado—open-side up—over a few pieces of sliced onion, can surprisingly help with any browning. The onion releases sulfur compounds that act as a natural preservative to help keep the avocado fresh for longer (roughly two days). The key to success with this hack is storing the two in an airtight, sealed container to help ensure the onion’s sulfur can work its magic.
Though we didn’t notice an overwhelming onion flavor in the avocado, you might want to skip this method if using the avocado in a sweet dish or smoothie.
5. Using lemon or lime juice to create a barrier
According to Chef Betsy Wiegand of Great White, a coastal-Californian cafe in Venice Beach, Calif., adding a squeeze of lemon to a cut avocado can help prevent browning. To further preserve its hue, she also emphasizes the importance of storing it completely covered to reduce the oxygen exposure. Due to the ascorbic acid (aka vitamin C) found in lemon or lime juice, adding citrus to an opened avocado helps create a barrier against oxygen that reduces oxidation. As the oxygen reacts with the acid in the juice, it slows down the chemical reaction and prevents browning for a few days. Although this method might add a slightly tangy flavor, it kept our avocados vibrant and fresh for about two days, making it the most effective one we tried. (And similarly, you can apply the same approach by brushing a thin layer of olive oil to shield the surface from oxygen exposure, but this will only work for a day or so.)
Bottom line? Next time you’re wondering how to keep avocado from turning brown, simply enlist some citrus juice.
How to ripen avocados quickly
In need a perfectly ripe avocado and all of the ones at the market feel like they’re hard as rocks? Chef Wiegand suggests wrapping it in a few sheets of newspaper. She notes that her family works in the agricultural business in the Fresno, Calif. area and has relied on this trick for years.
You can also place the unripe avocado in a paper bag and store it in a warm environment to expedite the softening process. Pairing the avocado with other fruits like bananas or apples can also help release a gas called ethylene that helps quicken the ripening process. The more you know, right?
Now that you have a perfectly ripe avocado on hand, find all the health benefits you’ll reap from it here:
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