Look at the skin. Sweet potatoes have thin, smooth skin that can be copper, red, or even purple. Yams have thick, bark-like skin that’s difficult to peel with a regular peeler.
Check the flesh. A classic orange sweet potato (the one you roast for Thanksgiving) is moist, sugary, and gets soft quickly. A true yam is pale or purple, feels tough, and needs longer cooking times.
Size is another clue. Sweet potatoes are usually modest, about the size of your hand. Yams can be enormous, sometimes as long as your forearm. Kind of intimidating, really.
Why This Matters for Your Dinner
Imagine you’re craving sweet potato fries. You grab a “yam” from the bin, expecting that caramelized, soft interior. Instead, you get a dry, dense fry that doesn’t brown the same way. That’s the difference in action.
If you’re making a sweet potato casserole with marshmallows, you definitely want the orange sweet potato. Using a true yam would give you a gluey, unsweet mess. No one wants sad marshmallows.
