The Science Behind How Sour Cream Can Keep Guacamole Nice And Green

Suppose you've effectively figured out how to get avocados to ripen faster and successfully made a batch of your one-of-a-kind guacamole to bring to your friend's house for dinner the following night. How will you keep that creamy dip from turning five shades of brown before the main event? Avocados are one of those rare nutritious fruits that have a very specific window of ripeness of 2-3 days, so making your favorite recipes and keeping them fresh for an extended period of time can be a tad stressful, even for the most experienced home chefs.

Once your avocado flesh has been exposed to outside air and oxygen, the clock starts ticking down to the moment the shelf life of this delicious snack falls to the wayside. Indeed, the mixture of oxygen and specific compounds in an avocado's flesh leads to browning over time. Luckily you can fix this oxidation with one milk-based condiment — sour cream. By adding your guacamole into a resealable container and adding a sufficient layer of sour cream on top followed by plastic wrap, you're essentially closing off your guacamole from outside air exposure. Before we reveal other ways to keep your next batch of guacamole green for a longer period of time, let's discuss how sour cream works to protect your guacamole against discoloration.

Whether you learn how to make your own sour cream or choose to buy a tub from the nearest grocery store, this dairy product has an important ingredient that fights against the breakdown of enzymes in avocado once it's been cut. Sour cream is primarily composed of cream and lactic acid that has been fermented over a period of time. This lactic acid bacteria provides a certain degree of acidity that fights against the oxidation process in freshly made guacamole. Essentially, you get two benefits from one product — by adding a layer of sour cream to guacamole, not only does the thick coating create a protective barrier between your guacamole and outside air, but the addition of lactic acid also works to keep your zesty dip fresh and green for as long as possible.

To use this convenient hack simply add your freshly made guacamole into an air-tight container and completely cover your avocado-based dip with a sufficient layer of sour cream followed by a tight-fitting lid or plastic wrap. Of course, if you're on the fence about using up all of your precious sour cream just to keep your bowl of homemade guacamole from turning brown, there's another way to incorporate this product into your next bowl of chip dip.

If adding a substantial layer of sour cream to your classic fresh guacamole recipe doesn't exactly seem practical, you can try mixing this fermented dairy product directly into your favorite recipe for added flavor and texture. Keep your guacamole recipe the same, but when preparing the ingredients, mash your avocados with ¼ cup of sour cream before adding in extras like chopped onion and cilantro. The tanginess of sour cream will add depth of flavor — and work to keep your guacamole fresh until chow time.

If you're still on the fence about incorporating sour cream into your favorite dip, try adding fresh lime juice on top of your freshly made guacamole instead. Limes contain a considerable amount of ascorbic acid — or vitamin C — which works to prevent oxidation just like the lactic acid in sour cream. Given the ingredients you may or may not already have on hand, adding extra lime juice may be a more practical option. 

As long as you aim to keep oxygen away from your freshly made dip and use one of these protective ingredients, your guacamole may last up to five days when stored properly in the refrigerator.