Lifelong avocado lovers know there is no greater mystery and pain than trying to figure out how to preserve leftover avocado. It seems any moment an avocado isn’t moving directly into your mouth, it’s actively turning brown, mushy and unappealing. Sure, you can always scrape the brown bits away, but guac being extra means it’s painful to waste.
To understand why it’s so hard to preserve, you have to understand what makes avocados turn brown in the first place. That could take a whole chemistry lesson, but the basics are: the phenols in the avocado react with oxygen to turn into another compound called quinone, which link together to create the brown pigment you see. And yes, it happens faster than pretty much every other commercial fruit.
You cut open an avocado to enjoy it and oxygen immediately starts reacting with the phenols, working to make your avocado flesh inedible. People have recommended all kinds of treatments to make avocados last longer. They’ve claimed that lemon juice, an ingredient regularly used as a preservative, can help. They’ve argued that leaving the pit in helps, covering the cut half of an avocado in water, even oil, can help.
If you’re tried these methods, you know they fall short. Several experiments online have shown as much. At best, you can expect a still-partly-edible avocado 24 hours later.
So what is the best method for preserving avocado?
A vacuum sealer.
Think about it: What does a vacuum sealer do? It removes the air (aka oxygen) from the container. What turns avocados brown? Air.
The trick is to act quickly after you’ve cut open the avocado. Either put the pit-containing side in the vacuum bag or quickly prep the avocado by mashing it and then vacuum sealing it. Some reports argue it can stay fresh for up to a week this way. If you follow the advice of the video, you can freeze the vacuum-sealed avocado as well. They won’t have the exact same texture when you defrost them, but they’ll still be edible up to two months later.
If you don’t have and aren’t willing to invest in a vacuum sealer, you can get a similar effect by tightly wrapping the avocado in plastic wrap or mashing the avocado, putting it in a zip-close bag and pressing the air out to the best of your ability.
Or, you know, just eat the whole darn avocado.