If you open an avocado too soon, there's a very simple trick to make sure that it still ripens with plenty of flavor. Just rub it with lime or lemon. Put it back together.
After speaking with avocado experts and running some in-house tests, we learned that avocados can continue to ripen after they've been cut. In fact, as long as you store the cut fruit properly and give it a few extra days, it will be just as creamy and rich as if you had opened it at peak ripeness.
Once you've let the feeling of disappointment wash over you, you may wonder, "Can you eat an unripe avocado?" The short answer is yes — unripe avocados have the same nutritional value, and if you're not allergic to avocados, eating an unripe one is perfectly safe.
Do not microwave your avocados or put your avocados in the oven to try to ripen them faster. If you do, the microwave or oven may soften the flesh of the fruit a little which may make it 'seem' ripe, but it isn't. The avocado will taste unripe and won't have the creaminess or buttery, nutty flavor we all know and love.
You know that thing about putting underripe fruit in a brown paper bag to make it ripen faster? Well, it actually works: Throw an unripe avocado into a paper bag with a ripe banana, fold down the opening, and leave it at room temperature on your countertop for a day or two to accelerate the avocado ripening process.
Avocados ripened in the refrigerator, whether in a bag or out in the open, took around four days to soften, but did so evenly. Stored in the fridge, they lasted a full five days before starting to show signs of over-ripening.
Placing an unripe avocado in the refrigerator will slow the ripening process, but the same concept applies to ripe avocados: put them in the refrigerator to keep them at their prime ripeness for longer. Avocados will freeze well, but this requires a bit more preparation.
Cold slows down ripening, so don't buy unripe avocados and put them in the refrigerator. They won't ripen properly, if at all.
Use or Store the Avocados
Once cut, it will be several hours—typically at least four hours—before the avocado starts to turn brown. Browning may occur more quickly if the avocado was overly ripe before blanching. If you are making guacamole, adding lime juice will help prevent browning even longer.
And while unripe avocados are known for being bitter, you'd be surprised how good your Guacamole will taste even when using semi-unripe avocados. Most peeps won't be able to tell the difference as long as you use plenty of salt and lime juice. What is this?
Bright green: If your avocado has a bright green color, this means that it is still around four to seven days from being ripe. Avocados this color will typically be hard to the touch and will need to rest on the counter for a few days—maybe even a week—before you can eat them. Underripe avocados tend to lack flavor.
Cut your avocado in half and fill a glass or plastic container near full with water. With the flesh-side down, place the avocado in the container, cover, and place in the fridge. This will keep the avocado from turning brown for about another two days.
If your avocado is rock hard and nowhere near ripe enough to eat, you'll need to rely upon your oven. Preheat your oven to 200 degrees Fahrenheit. Without cutting into the fruit, wrap the avocado in aluminum foil, and bake on a sheet pan for ten minutes. Check for ripeness.
How to "ripen" an avocado in the oven. Preheat the oven to 200°F. Wrap an avocado in foil and bake, checking every 10 minutes, until the avocado is soft enough to use.
To speed up the avocado ripening process we recommend placing unripe avocados in a brown paper bag with an apple or banana for two to three days until they are ripe. We do not recommend any other method of ripening avocados.
To ripen an avocado quickly on the counter, place it in a bowl or paper bag next to an apple or banana. To make the avocado ripen in 1-2 days, place it in a paper bag with a banana or two. Avoid using plastic bags that stifle the fruit.
Properly timing the picking is important, as the only reason that an avocado will not ripen is if it is harvested prematurely or stored improperly, in cool conditions. If an avocado is picked too soon, it has a low oil content and will never ripen sufficiently, remaining inedible and rubbery, with poor flavor.
Unripe Avocado Guac
Add a touch of salt and pepper, lime juice (fresh squeezed is best), and any extra vegetables you'd like. The most popular are tomatoes, peppers, onions, or jalapeños. Adding more of these different ingredients will distract from the slightly bitter taste of the unripened avocado.
Just coat both halves of your avocado with fresh lemon juice (lime will work too), then put back together and wrap tightly in cling film. Whack it in the fridge and check back the next day. It may need a little longer depending on how hard it was when you sliced it open, but eventually it'll ripen up nicely.
The darker the color, the riper the avocado.
Olive oil: Brushing an avocado half with olive oil is said to reduce contact with air, preventing oxidation. This method held up for us, with minimal browning happening around the edges, but with most of the interior flesh remaining a vibrant green.