How can I speed up banana ripening?

Question

I need to make banana bread tomorrow, and the bananas I recently purchased with this in mind to not appear to be ripening fast enough. Is there anyway to speed the ripening without spoiling the bananas altogether?

(I have looked at this answer and it refers to how the fridge will speed up "blackening". @Sarge_Smith describes it as a different process chemically, so I am unsure that blackening == ripening for the purpose of making banana bread.)

Answer 1

Bananas are imported unripe and then ripened in the country of sale. This ripening is achieved by forcing ethylene gas through the bananas in special pressurised rooms.

Bananas naturally produce ethylene as they ripen, so you could just put them in a sealable plastic bag to contain that gas. Tomatoes also produce ethylene, so you could pop a couple of those in as well, but be aware that they'll also ripen faster too.

Answer 2

When bananas are sealed inside plastic bag, the skin turns black and aesthetically it does not look good. Also, some times black banana may be not fully ripe. As ElendilTheTall says, its better to use ethylene so that banana can be ripened at a faster rate.

There are couple of ways wherein banana can be ripened on a domestic scale.

1. As Aaronut says, cover in paper bag and keep it in warm place, thereby self produced ethylene can be trapped whcih makes banana to ripe.
2. Coat the tip of the banana with some calcium salt, like slaked lime or quick lime, and keep it warm place.
3. Expose the banana to fumes (by burning some dry biodegradable material, like dry leaf, dry stem or such things) and cover the exposed banana tightly.

Answer 3

There is also another method, that only takes 20 minutes. Heat it up in a oven.

Ripe bananas super fast in the oven:

Prepare the fruit with a few puncture holes and enclose them

150°C (302°F ; 130°C Fan, 266°F Fan)

• mashed for Banana bread

80°C (176°F ; 60°C Fan, 140°F Fan)

• soft but chunky

Put in the oven for a good 20 minutes, until the peel of the banana turns brown.
The heating of the fruit will make it soft and very sweet.

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The images show middle ripe, slightly spotty, bananas.
Adjust time, when needed (less ripe / more ripe)

Ripe bananas super fast in the oven 20 minutes Goal: small, soft chunks
213g punch holes with fork
after 20 minutes heating with 80°C (176°F ; 60°C Umluft, 140°F Fan)
138g slice into small,soft chunks

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Ripe bananas super fast in the oven 20 minutes Goal: very soft for mashing
225g punch holes with fork
after 20 minutes heating with 150°C (302°F ; 130°C Fan, 266°F Fan)
135g slit opened and spoon out or squize out
135g after a minimal amount of stirring
Result after using the mashed banana as Jogart replacement and the chunks of the banana replaced the apples

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Answer 4

I know that this is a bit after the fact, but here is a trick I learned from the Produce Manager at the supermarket I used to work at...

Put the banana in a paper bag with an orange. Close the paper bag (roll it up). Leave it over night, and the banana will be ripe in the morning.

The paper bag was mentioned before, as was using an apple, but citrus works even better.