How to ripen an avocado faster:
You will need
- an avocado,
- an apple (bananas and tomatoes work too),
- and a paper bag (or a wrapped up newspaper).
Put the apple and avocado in the paper bag together. This will trap the ethylene gas that is being produced, and it will accelerate the ripening process. Ethylene is a natural plant hormone. It is a very simple organic compound.
Avocados are unique because they are climacteric, which means they will mature on the tree but ripen off the tree. That is why it is so common to get avocados that are under-ripe from the store. Some stores will use synthetic ethylene gas to ripen them, but this is cheap and easy to do yourself.
If you want to speed up the ripening process, just increase the number of apples, bananas, or tomatoes that you put in the bag with the avocado. The idea here is that each one is producing ethylene gas, and you are creating a gas chamber for it to be trapped within. So the greater the number of ethylene producers you use, the more you will accelerate the ripening process.
Ethylene gas has actually been used since ancient Egypt to ripen fruit. They would gash figs, because wounding plants stimulates ethylene production.
I hope this was helpful. Enjoy your delicious avocado!