The sap is not only safe to consume, but some food experts even claim that the more the sweet potato secrets, the sweeter its overall flavor is. The more sugar and water are present in the sweet potato, the more sap the potato will secrete. The sap is also indicative of freshness, as sweet potatoes dry out over time, meaning the juicier your potato is, the fresher it must be (via Cooking Chew). Also, according to FoodsGuy, studies and surveys have found that sweet potatoes grown en masse are significantly less sappy than their organic counterparts. Still, whether the lack of sap in mass-grown sweet potatoes is due to pesticide usage, genetic modification, or some other factor is unknown.
If you cut into your potato and find some of the flesh is not stained white by the sap but instead is actually white itself, you may have stumbled upon a mislabeled yam. According to MerchDope, yams are often mislabeled in North America, and so often people will find sweet potatoes and yams mixed together at the grocery store. No matter if you see it coming out of a yam or sweet potato, don’t be afraid to taste the white liquid, as it’s completely safe to digest, even if just to have a better understanding of the food you’re cooking and consuming . Just as some ingredients can change your sweet potatoes forever, so this white ooze might change how you view this vegetable.