Whether or not you’re a fruit lover, you’ve probably heard that you should store unripe fruit in a brown paper bag to speed up the ripening process. But do paper bags really help fruit ripen? And if yes, how ?

The answer depends on the fruit.

It’s not the color of the bag, it’s the material

It’s true, some fruits do leak gas – ethylene gas to be exact. It is released through the growing tips of roots, flowers, damaged tissue (i.e. bruising) and during maturation. This hormone is responsible for several effects of the plant, one of which is ripening. As the fruit ripens, ethylene converts the starch in the flesh of the fruit to sugar, creating a sweeter, tastier fruit.

When a fruit producing ethylene gas is placed in an enclosed environment like a paper bag, the gas begins to build up around it, essentially giving it a healthy dose of the elixir of ripening. And so the fruit ripens faster. You can even add a piece of ripe fruit to unripe fruit for an extra boost of ethylene.

Plastic bags can also trap ethylene gas, but they are not breathable. Thus, they also trap moisture which can cause the fruit to rot before it ripens. Paper bags – whether brown or white or any color in between – are ideal because they promote air circulation. But these are not the only ideal ripening containers. You can also store ripening fruits in other breathable materials such as cotton cloth or even bowls of rice (although this option is not ideal for softer-skinned fruits like peaches).

Which fruits ripen after picking?

There are two classifications of fruits in the field of ripening – climacteric and non-climacteric. In short, climacteric fruits produce ethylene gas and continue to ripen after being picked, unlike non-climacteric fruits and therefore should only be picked when fully ripe.

Climacteric fruits include:

  • apricots
  • lawyers
  • bananas
  • Kiwi fruit
  • mangoes
  • nectarines
  • peaches
  • pears
  • plums
  • tomatoes

Non-climacteric fruits include:

  • apples
  • coconut
  • cherries
  • grapefruit
  • Grapes
  • oranges
  • Pineapple
  • strawberries
  • tangerines
  • watermelons

The best time to eat a fruit, of course, is when it’s ripe, because it’s at its peak in terms of flavor and texture. But climacteric fruits are picked and sent to the supermarket before they are ripe. This is because many soften as they ripen, making them susceptible to bruising and rotting. Harvesting them when they are still firm and unripe helps minimize damage in transit and extends shelf life. When you bring them home, let them ripen for a few days before eating them.

Non-climacteric fruits, on the other hand, will not continue to ripen or become sweeter once removed from the plant. Thus, they should remain on the plant until they reach full maturity and be eaten soon after.