A Give and Take

• The ripening process between the tomatoes and banana works both ways. Not only will a ripe banana placed in a paper bag with green tomatoes turn the tomatoes red, the tomatoes will also ripen the banana even more. Both fruits and vegetables give off the same gas as they ripen, so it stands to reason that everything in the bag will eventually turn. Just as a ripe banana turns green tomatoes red, red tomatoes help to turn green bananas yellow.

It’s About Gas

• Fruits and vegetables give off ethylene gas as they ripen. When the banana and tomatoes are placed inside a closed paper bag together, the ethylene gas stays trapped inside, speeding up the ripening process. How fast the ripening happens depends on just how much gas the banana and tomatoes are giving off. In most cases, the ripening process happens over a series of days, requiring daily checks of the bag for signs of ripening.

Sweet Sacrifice

• Although the ethylene gas is a natural part of the ripening process, there is nothing natural about forced ripening in a bag. Tomatoes that ripen on the vine have the benefit of not only oxygen and ethylene gas, but also the light and heat of the sun. All of these elements aid in converting starches to sugars as the tomatoes turn red. Tomatoes that ripen in a paper bag will not have the same sweet taste as vine-ripened tomatoes.

How it’s Done

• To get the ripening underway, place several green tomatoes into a brown paper bag with a ripe banana and close the paper bag. Open the bag every day and check for ripening. If the tomatoes have not turned red, close the bag and wait another day. If upon opening the bag, you notice that the banana is starting to turn mushy, remove it and replace it with another. Continue the process until the tomatoes ripen.