Why do watermelons burst or foam?

Hidden beneath its refreshing sweetness, a curious phenomenon occurs – watermelon explosions and the unexpected release of foam

One of the most surprising occurrences related to watermelons is their tendency to burst, sometimes with explosive force. The primary reason behind this phenomenon is the internal pressure build-up. As the watermelon grows on the vine, its water content increases, causing the cells to expand. However, the rigid outer rind restricts the expansion to a certain extent. This results in a significant amount of internal pressure being exerted on the fruit’s structural integrity.

In some cases, when the internal pressure becomes too great for the rind to contain, it gives way, leading to the watermelon bursting open. This release of pressure is often accompanied by an audible pop and can be quite spectacular. Factors such as overwatering, rapid growth due to excessive fertilization, or certain environmental conditions can contribute to an increased likelihood of bursting.

Another intriguing occurrence involving watermelons is the formation of foam or froth inside the fruit. This captivating phenomenon traces its origins to fermentation, in which naturally occurring bacteria within the fruit revel in sugar, leading to the production of carbon dioxide.

When microbes enter the watermelon and start fermenting the sugars in its flesh, carbon dioxide gas is released. Since the watermelon’s flesh is mostly composed of water, the carbon dioxide gets trapped within the liquid, forming bubbles that resemble foam. This foam can accumulate and become visible through cracks or openings in the rind. If the internal pressure intensifies, your watermelon might be on a trajectory toward exploding.