Exploding watermelons: Montrealer surprised after fruit explodes in heat

A Montrealer was surprised after a watermelon he purchased exploded on his kitchen counter.

As Montrealers find ways to keep cool during this intense heat wave, a warning – keep a close eye on your watermelons.

One CTV News viewer wrote in to say his newly purchased watermelon exploded on his kitchen counter just hours after he brought it home.

“It’s actually a very natural process of fermentation, ” said Sylvain Charlebois, a food industry expert and visiting professor at McGill University.

“Sugar gets converted into gas inside the watermelon when it gets really, really hot, especially in the summer,” he said, noting that it’s actually not that uncommon to see foam oozing from a watermelon, or for it to actually explode if too much pressure builds up inside the thick peel.

“You can easily make a natural bomb out of it,” Charlebois said, “because it’s so tight and the gas will stay inside.”

The fermentation process can start if the watermelon is left inside a hot car for too long, or if it’s over 30 degrees inside your house, explained Charlebois. But, he adds, it’s also important to check watermelons in the store for bumps or dents – signs it may have already started to ferment.

“Sometimes there’s a breach in the cold chain which could actually trigger the process of fermentation prematurely,” Charlebois said.

Watermelons are supposed to be transported in refrigerated trucks cooled to three degrees Celsius, but sometimes unreported mechanical failures can expose the melons to prolonged extreme heat without the grocers ever knowing.

“By the time the product gets to the store,” Charlebois said, “it’s already too late.”

According to Charlebois, that’s most likely the reason why the watermelon in the picture sent in by our anonymous viewer exploded.

Watermelons that are showing signs of fermentation should not be eaten. Instead, Charlebois recommends taking it back to the store for a refund.