We've all been there. You make a big batch of guacamole the night before your big party, only to find that the top 1/2-inch or so has turned at least three shades of gray-brown. Sure, you could scrape it off, toss it in the trash and transfer the rest (now greatly reduced) to another bowl. But, what a waste!
We were certain that there has to be a better way, so we tested out six methods to help you avoid the pitfalls of discolored guacamole. Here, we reveal which ones work best so you always know how to keep your guacamole green.
Method #1: Top with lime juice and plastic wrap
Avocados and most other fruits and veggies contain an enzyme (polyphenol oxidase) that reacts with the oxygen in the air and turns the flesh a dull shade of drab, known as oxidation. Limes are very acidic and contain loads of ascorbic acid, aka, vitamin C, which combats the enzyme. The fix? Drizzle a shallow but visible layer of lime juice onto the guacamole surface (first making it as smooth as possible) and cover with plastic wrap, pressing it directly onto the surface. The next day, either pour it off or stir it in for an especially tart guac.
The verdict: The color stays vibrant and if you like a little extra tang in your dip, this might become your go-to.
Method #2: Top with sour cream and plastic wrap
The lactic acid in sour cream acts very much like the ascorbic acid in limes in combating the oxidizing enzymes in avocados. The process and result is similar: spread a thin layer of sour cream onto a smooth surface of guacamole and cover with plastic wrap, pressing it directly onto the surface. When ready to serve, either scrape it off or stir it in for a creamy guacamole.
The verdict: This is fine if you already have sour cream in the fridge, but certainly not worth a special trip or the added expense.
Method #3: Top with plastic wrap alone
Wondering what would happen if we didn't have lime juice or sour cream on hand, we tried this approach.
The verdict: Pressing plastic wrap directly onto the surface without adding lime juice or sour cream is not a flawless option. If the surface of the guacamole isn't entirely smooth or the plastic isn't entirely flush, there will be air pockets where oxidation will occur.
Method #4: Guac-Lock
This single-use gadget works similarly to plastic wrap, except it's super cute. The basic premise is that all of the air is pressed out, creating an airtight lock on your guac. The bowl and lid have tight-fitting gaskets and the bottom can be pushed up to eliminate the space between the guacamole and lid.
The verdict: It definitely works! The only downside is when removing the lid, a good bit of the guac comes off with it and needs to be scraped back into the bowl. $19.99, casabella.com
Method #5: Add the pit and top with plastic wrap
Some people swear by this one, so we had to put it to the test.
The verdict: Contrary to popular belief, adding the avocado pit to guacamole does not prevent oxidation. In fact, if it sticks out above the surface, it creates air pockets that prevent the plastic wrap from adhering tightly enough. Sorry abuela—I still love you!
Method #6: Top with water and plastic wrap
Water is completely neutral both in flavor and pH level. It won't actively combat the oxidizing enzymes, but it will act as a very effective barrier if the layer is thick enough. Drizzle a 1/2-inch deep layer of water onto the smooth surface, cover with plastic, pressing it gently, but directly onto the surface. The next day, pour it off and stir just before serving.
The verdict: This is the most effective and least expensive way to preserve color and maintain flavor.
Whether you use lime juice, sour cream, plastic wrap, a cute gadget, or water, keeping your guacamole green is ultimately all about creating a strong barrier between guac and outside world. Now, go forth and guac-on!
Here are delicious guacamole recipes to try:
Spice up your guac with chopped garlic and finely chopped red chiles.
Try topping your guacamole with fresh cilantro, shredded cotija cheese and homemade pico de gallo to represent the green, white and red colors of the Mexican flag.
Finely chopped apple and fresh mint give it an unexpected twist.
Guacamole doesn't always have to be savory. Sweeten it up with pomegranate seeds and grated coconut.
Set up a guacamole bar so your guests can customize their dip with smoky bacon crumbles and more.
This article was originally published September 16, 2016.