We recently saw a piece online claiming that you can ripen rock-hard avocados by baking them in a low oven, which in theory puts the ripening process into hyperdrive. We had to try it out.
Following the instructions, we wrapped a few unripe avocados in foil and placed them in a 200-degree oven. To our disappointment, after a full hour, all that had happened was that the outer portion of the avocado’s flesh had turned soft but slimy, while the interior had remained firm. A check-in with our science editor revealed why it didn’t work: Avocados ripen thanks to ethylene gas, a hormone that triggers enzymes in the fruit to convert starches to sugars and soften cell walls. While heat does stimulate the production of ethylene gas, there is a limit to both the rate of its production and the ripening reactions it produces—you can speed the process up only so much. Placing an avocado in a 200-degree oven doesn’t actually produce more ethylene or ripen the fruit—it merely cooks it, which is why our avocado turned slimy rather than softened like a truly ripened fruit.
Our suggestion? Don’t turn on the oven. Just plan ahead and let your avocados ripen on the counter. You can also put your unripened avocados in the refrigerator, but be sure to allow a few days longer for ripening.