The Unexpected Way Mason Jars Can Help Keep Your Bananas Fresh

The mason jar has arguably been one of the handiest kitchen utensils for more than a century. Not only is it the perfect fix for fresh wine without a cork, but it's also one of the most cost-effective decanters — and now, it's a clever way to keep your bananas fresh. In the past, when I've eaten half a banana and wrapped the rest in its peel, I've often returned to a semi-browned half that made me want to incorporate it into a quick and easy banana bread recipe (albeit with delicious results). But by storing that banana half in a mason jar, anyone can keep it fresh, even after 36 hours.

According to food preservation blogger Amy Cross, the best way to keep bananas fresh is to cut them in half with the peel on and place them in a wide-mouthed mason jar. Seal the jar and store it in the refrigerator, and you can enjoy the fruit the next day. For the sake of experimentation, the kitchen expert also carried out this banana hack for a week, then continued for another week, and finally for a month. Thirty days later, the banana halves were still fresh. 

There was no browning, no black spots, and the fruit maintained its firm texture, with only a slight softness that typically develops much quicker with traditional storage methods. This genius hack can help you avoid wasting banana pieces — whether you took a bite and left some, or a toddler couldn't finish the entire fruit. And there's a scientific explanation as to why it works.

A sealed mason jar creates the ideal conditions for keeping a banana fresh when the peel is intact. This is due to the enzymes that are contained in fruit, which react when exposed to oxygen and cause the fruit to ripen. That's ideal when the fruit is firm or green, but when you slice an already ripe banana, this enzymatic reaction leads to further ripening beyond the "soft" stage and eventually results in a mushy texture. By sealing a sliced banana in a mason jar, you cut off its oxygen supply, halting this process. This helps prevent the fruit from becoming soft and browning. Keeping the peels intact also minimizes the amount of banana flesh exposed to air. 

Additionally, slicing the banana in half instead of cutting it into smaller pieces helps it stay fresh for longer. Even when peeled, cutting a banana into smaller pieces increases the surface area exposed to oxygen, which can cause the fruit to lose its freshness. Therefore, it's best to leave the banana in halves. 

That said, if you find yourself in a crisis — or there's another mason jar shortage, like in 2020 — there are other methods to keep banana halves and slices fresh. For example, you can sprinkle them with lemon or pineapple juice, which lowers the pH levels and helps prevent browning. Keep in mind, though, that this method will only keep your bananas fresh for three to four days, which is all the more reason to go bananas over mason jars!