Ever cut into a potato and discovered black spots inside? These spots — small or large — can look concerning, but they’re usually nothing to worry about.

So what causes these black spots, and is it safe to eat potatoes that have them?

The black spots in potatoes are simply bruises from handling. While potatoes with these spots are still edible, it’s best to cut away the bruised parts since they often taste bitter.

Potatoes — the starchy tubers of Solanum tuberosum originally from the Americas — are quite hardy compared to other vegetables. When stored properly in a cool, dark place like a cabinet or pantry, most varieties keep for weeks and may even develop more flavor over time.

However, potatoes bruise when mishandled. When thrown into baskets or stacked heavily, the force damages their cell walls, creating those black spots. This damage can happen during harvest, packaging, shipping, retail display, or even when you handle them at home.

When a potato gets bruised, the damaged cells release compounds called phenols. Enzymes then oxidize these phenols to form melanin — the same pigment that gives color to our hair and skin. According to Colorado State University researcher Sastry Jayanty, this discoloration takes 24-48 hours to appear after bruising.

While the discoloration looks unappealing, the real issue is taste — bruised areas often develop a bitter flavor. Though generally safe to eat, it’s best to cut away these spots before cooking.

How to Spot Good Potatoes at the Store

Unlike bruised apples or bananas, potato damage isn’t easily visible through their thick skin. Here’s how to choose good ones:

Look for firm potatoes without blemishes, bruises, or cuts. As culinary expert Harold McGee advises in “Keys to Good Cooking,” avoid potatoes with green surfaces or sprouts, which contain bitter, toxic alkaloids.

If you see store employees pouring potatoes from a height into display bins, remember that some will likely develop bruises within a day or two.

Once potatoes are in your cart, handle them gently. They’ll reward you with better flavor when treated with care.

Other Types of Potato Discoloration

Cut potatoes left exposed to air will soon brown on their surface. This “enzymatic browning” — the same reaction that causes internal dark spots — also affects apples, avocados, and bananas. You can prevent this by applying something containing vitamin C (ascorbic acid), like lemon juice.

Don’t confuse bruising or enzymatic browning with spoilage. Spoiled potatoes show signs of fuzzy mold, mushiness, or off odors and should be discarded.

Storing Potatoes Properly

Store potatoes at room temperature (68-72°F) in a cool, dark place like a cellar, basement, or pantry. These areas should be moderately dry and well-ventilated.

Avoid refrigerating uncooked potatoes — cold temperatures trigger processes that increase sugar content, resulting in darker cooked potatoes that absorb too much oil.

According to Oregon State University, long-lasting potato varieties include Elba, Katahdin, Red Chieftain, Yukon Gold, Burbank Russet, and German Butterball. Clean off soil before storing, especially if it’s sandy, and ensure potatoes are completely dry after washing.