Walk into any American grocery store in October and you'll see bins labeled "yams" and "sweet potatoes." Most of them are the same thing. The ones labeled "yams" are almost certainly sweet potatoes — specifically orange-fleshed varieties like Beauregard or Garnet. True yams (a completely different species) are starchy, rough-skinned tubers from West Africa and rarely show up in US stores.
The confusion goes back to the slave trade. Enslaved West Africans called the orange sweet potatoes they encountered in America "yams" because they resembled the yams they knew back home. The name stuck. Then in the 1930s, growers started marketing orange-fleshed sweet potatoes as "yams" to distinguish them from the paler, drier varieties. The USDA now requires "yam" labels to include "sweet potato," but the damage is done. Americans still use the terms interchangeably.
For cooking purposes, it doesn't matter what you call them. What matters is which variety you buy and how you cook it.
Know your varieties (and what to buy)#
You'll encounter three main types at the store, all sweet potatoes despite what the label says.
| Variety | Skin | Flesh | Texture | Sweetness | Best for |
|---|---|---|---|---|---|
| Beauregard | Light copper | Bright orange | Stringy, moist | Very sweet | Casseroles, mashing, pies |
| Jewel | Smooth copper | Orange | Fluffy, dry | Moderate | Roasting, fries, savory dishes |
| Garnet | Dark red-orange | Deep orange | Very moist, dense | Very sweet | Baking whole, pies |
Beauregard is the default. If the bin just says "sweet potato" with no variety listed, it's probably Beauregard. Developed at Louisiana State University in 1987, it's the most widely grown variety in the US. Very sweet, very orange, slightly stringy when cooked. Works for everything but especially good for mashing and casseroles.
Jewel is less sweet and fluffier. It holds its shape better when roasted, which makes it better for cubed applications like roasted sweet potato salad or grain bowls. Slightly savory flavor means it pairs well with spicy or salty components without tipping into dessert territory.
Garnet is the moistest. Dark skin, deep orange flesh, almost pumpkin-like when baked. Best for baking whole or pies where you want maximum moisture and sweetness.
What to look for: firm tubers with smooth, unblemished skin. Avoid soft spots, sprouts, or cracks. Smaller sweet potatoes (6-8 oz) cook faster and more evenly than baseball bats. Medium-sized ones (8-12 oz) are ideal for baking whole.
Store them like onions, not potatoes#
Sweet potatoes are tropical tubers. They don't like the cold. Do not refrigerate them unless they're already cooked.
Store them in a cool, dark, well-ventilated spot — a pantry or cupboard away from the stove. Not in a sealed bag. Not next to onions (which release gases that speed up spoilage). Just loose in a basket or box.
They'll keep for 2-4 weeks at room temperature. Once you cook them, refrigerate leftovers in an airtight container for up to 5 days.
How to cook them (ranked by results)#
1. Roasting whole (best for sweetness and texture)
This is the gold standard. Slow roasting at moderate heat converts starches to sugars and gives you creamy, caramelized flesh.
Method: Preheat oven to 400°F. Scrub sweet potatoes clean. Pierce each one 4-5 times with a fork (so they don't explode). Place directly on the oven rack with a sheet pan on the rack below to catch drips. Roast 45-60 minutes depending on size. They're done when a knife slides through with zero resistance.
Why it works: The low-ish heat (compared to roasting vegetables) gives enzymes time to break down starches into sugars. You get maximum sweetness and that silky texture.
Bonus move (if you have time): Hold them at 150°F for an hour before roasting. This activates amylase enzymes that convert even more starch to sugar. You can do this in a cooler with hot water (Kenji López-Alt's method) or just roast at 150°F for an hour, then crank it to 400°F for another 30 minutes.
2. Roasting cubed (best for sides and salads)
Faster than whole roasting and you get crispy caramelized edges.
Method: Preheat oven to 425°F. Peel and cut sweet potatoes into 1-inch cubes. Toss with olive oil, salt, and pepper. Spread in a single layer on a sheet pan (don't crowd). Roast 25-30 minutes, flipping halfway. Done when edges are browned and crispy.
Why it works: Higher heat, more surface area, faster caramelization. The edges get crispy while the centers stay creamy.
Pro trick for extra crispiness: Parboil the cubes first in salted water with a pinch of baking soda (3-5 minutes until just tender). Drain, let them steam-dry, then toss with oil and roast. The baking soda roughens the surface and draws out starch, which crisps up beautifully.
3. Boiling (only if you're mashing or in a rush)
Boiling is fast but you lose flavor and texture. The sweet potatoes get waterlogged and bland. Only do this if you're mashing them and can't wait 45 minutes for roasting.
Method: Peel and cut into 1-inch chunks. Boil in salted water 12-15 minutes until fork-tender. Drain immediately and let steam-dry for a minute before mashing.
Why it's not ideal: Water dilutes flavor. You also don't get any caramelization. Roasted sweet potatoes mashed with butter taste infinitely better than boiled ones.
Even for mashed sweet potatoes, roast them whole first, then scoop out the flesh and mash. Way more flavor.
Peel or don't peel?#
For roasting whole: don't peel. The skin protects the flesh and peels off easily after cooking.
For roasting cubed: peel first. The skin doesn't crisp up and just gets leathery.
For boiling or mashing: peel first unless you like fibrous bits in your mash.
How to use them beyond the Thanksgiving casserole#
Sweet potatoes work in savory contexts just as well as sweet ones. They're starchy enough to anchor a meal and sweet enough to balance spicy or salty flavors.
Savory ideas:
- Roasted cubes tossed with tahini, lemon, and za'atar
- Mashed with miso butter and scallions
- Sliced thin and roasted as "fries" with smoked paprika and garlic
- Cubed and added to chili or curry
- Smashed and fried like crispy smashed potatoes
Sweet ideas:
- Baked whole, split, topped with butter and cinnamon
- Mashed into pancake or waffle batter
- Pureed into pie filling or quick bread
- Roasted and blended into soup with ginger and coconut milk
What about purple sweet potatoes?#
They exist. They're less common in US stores but you'll see them at farmers markets and Asian groceries. Purple varieties (like Stokes Purple or Okinawan) are drier and less sweet than orange ones. They're starchy, almost chestnut-like, and hold their shape when cooked. Best for roasting or steaming, not for mashing or pies.
The purple color comes from anthocyanins (same antioxidants in blueberries). They don't taste wildly different but they look cool.
The sweet potato casserole question#
You know the one. Mashed sweet potatoes topped with marshmallows and baked until gooey. It shows up at Thanksgiving and divides families.
If you're making it, roast your sweet potatoes whole first. Don't boil them. You want all the natural sweetness and caramelization. Skip the added sugar if your sweet potatoes are already sweet (Beauregard or Garnet varieties don't need help). Use brown sugar only if you're using Jewel or another less-sweet variety.
And if you hate marshmallows, a pecan streusel topping (butter, flour, brown sugar, chopped pecans) is objectively better.
Cook times and temps (quick reference)#
| Method | Temp | Time | Notes |
|---|---|---|---|
| Roast whole | 400°F | 45-60 min | Pierce first, check with knife |
| Roast cubed | 425°F | 25-30 min | Single layer, flip halfway |
| Parboil + roast | Boil 3-5 min, then 425°F | 20-25 min | Baking soda in water for crispiness |
| Boil (chunks) | Rolling boil | 12-15 min | Salted water, drain well |
| Microwave whole | High | 5-8 min | Pierce first, flip halfway |
Frequently asked questions#
Can you eat sweet potato skins?
Yes. The skin is edible and nutritious (fiber, vitamins). If you roast whole sweet potatoes, the skin gets tender and slightly chewy. If you roast cubed sweet potatoes with the skin on, it gets leathery and unpleasant. Peel them for cubed applications.
Do sweet potatoes need to be peeled before cooking?
Not if you're roasting them whole. The skin protects the flesh and peels off easily after cooking. For cubed roasting, mashing, or boiling, peel them first. The skin doesn't add anything and can make the texture unpleasant.
Why do my roasted sweet potatoes turn out mushy?
You're overcrowding the pan. Spread them in a single layer with space between cubes. Overcrowding traps steam, which makes them soggy instead of crispy. Also make sure your oven is fully preheated and don't flip them too early — let them sit undisturbed for at least 12 minutes to develop a crust.
Can you freeze cooked sweet potatoes?
Yes. Roasted or boiled sweet potatoes freeze well for up to 3 months. Let them cool completely, pack in airtight containers or freezer bags, and label with the date. Reheat in the oven or microwave. They'll be softer than fresh but still good for mashing or pureeing.
What's the difference between sweet potatoes and regular potatoes?
Different species entirely. Sweet potatoes (Ipomoea batatas) are root vegetables in the morning glory family. Regular potatoes (Solanum tuberosum) are tubers in the nightshade family. Sweet potatoes are sweeter, denser, and more nutritious (more fiber, vitamin A, and antioxidants). Regular potatoes are starchier and more neutral in flavor.
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