Avocados are insanely popular (we ate 4.25 billion in the U.S. in 2015), delicious and have the power to make me order a sandwich I was not previously interested in until I spied it on the ingredients list.
Perhaps the only bad thing about an avocado is its lasting power, or lack thereof: If you don’t use the whole thing right away, it becomes a mottled, brown mess that’s less appetizing than its previous buttery green form.
But what if there was a way to stop avocados from browning? In order to do that, it’s important to understand why avocados turn so rapidly. It’s all thanks to an enzyme called polyphenol oxidase, which causes the fruit to go murky when it's exposed to air. A little browning is inevitable, but to keep avocados from going completely dark, you want to create as tight a barrier against oxygen as possible.
We halved a bunch of avocados and tried the five most popular methods to
thwart science prevent browning overnight. There were some clear winners and losers, and a lot of weird pros and cons to each.
The benchmark against which we compared all of our avocados: A plain ol’ halved avocado, wrapped tightly in plastic wrap. You want to limit the fruit's exposure to oxygen, so the tighter the seal the better. Plastic wrap is great because it clings directly to the surface of the fruit—but some air pockets, and therefore some browning, are inevitable. As you can see, this method resulted in a heavily browned fruit.
Hack #1: Oil
Viscous and silky, oil is a great barrier against oxygen. We rubbed our halved avocado with a generous layer of olive oil to protect the fruit from browning, and it worked. The half stayed nice and green, but the avocado became a little mushy and the oil affected the flavor of the fruit. This is a great trick if color is the single most important thing to you in an avocado, but since it compromises the flavor and the texture, it’s not my first recommendation.
Hack #2: Onion
Sulfur dioxide, a compound found in onions, is used to preserve the color in dried fruit, so it should theoretically hold true for fresh fruits too. We sliced a ring of white onion and pressed it against the cut side of the avocado and bound both in plastic wrap. The result? There was some browning, and of course an avocado that’s heavily onion-scented. For me, that’s enough of a turn off to skip this hack, but if an avoconion sounds good to you, proceed at will.
Hack #3: Pit
I cannot count how many times I’ve been told that leaving the pit in an avocado will keep it from turning brown. I was a skeptic. I figured that the portion of the fruit that’s in contact with the pit wouldn't brown because it’s hasn’t yet been exposed to oxygen, but what about the rest of the surface that has been in contact with air? Plus, won’t the bulbous pit result in plastic wrap that's tented with lots of the air pockets that are famous for browning avocados? I thought yes, but I thought wrong. This method was the simplest, and resulted in a reasonably green avocado. The flavor and texture wasn't compromised, making this my top pick for 'cado preserving.
What not to do: Lemon and water
A generous squeeze of lemon atop my cut avocado has always been my go-to for preserving its color. Citric acid is supposed to slow browning and is recommended by science-loving chef Alton Brown. But results don't lie. I was dismayed to find that the lemon avocado turned as brown as the untreated avocado.
It makes sense why restaurant chefs submerge cut avocados in water: If something is submerged in water, there is no air contact. But unlike chefs, most of us need to store our sliced ‘cados for more than a few hours. As expected, the fruit emerged soggy and water-logged.
Keep that pit. It’s simplest way to preserve a beautiful avocado. It’s not perfectly green, but this method still preserves the flavor and texture whereas the oil and onion methods alter the fruit. But really, at the end of the day, a little brownness should never deter you from feasting on an otherwise perfectly delicious avocado.