How to Cook Purple Sweet Potatoes (7 Methods)

If you’re wondering how to cook purple sweet potatoes, they can be baked, steamed, roasted, microwaved, air fried and more. Find out here why they need cooking for longer than other sweet potatoes, plus all sorts of other purple sweet potato facts. 

Purple sweet potatoes have been appearing more and more in shops and at markets during recent years. This type of potato is prized for its nutritional benefits, including antioxidant properties.

Due to this growth in popularity, purple sweet potatoes are now grown globally, particularly in Japan and the US. They have skin that’s purple or reddish in color and purple flesh with a dense texture. Purple sweet potatoes are packed with antioxidants and anthocyanins.

While they may not be found as easily as orange or white sweet potatoes, the purple variety is often available at green groceries and food markets. You can cook them in much the same way as the more widely available ones with white or orange flesh. It can take a little longer, though, due to their denser, drier texture. 

Purple sweet potatoes can be used in both sweet and savory dishes. They can be baked, boiled, fried, grilled, roasted, steamed or deep-fried.

Purple Sweet Potatoes vs Regular Sweet Potatoes

Apart from the bright violet flesh, the key difference between orange or white and purple sweet potatoes is the nutritional value. Orange sweet potatoes are rich in beta carotene, while purple sweet potatoes are richer in antioxidants and anthocyanins. Perhaps surprisingly, the nutritional value is enhanced when purple sweet potatoes are cooked. 

Purple sweet potatoes have denser, drier flesh and thus need longer cooking times plus the use of water. Once cooked, they have a creamy texture plus a rich, rounded flavor.

Different Types of Purple Sweet Potato

The sweet potatoes you’ll come across are likely to be either Okinawan sweet potatoes or Stokes Purple® ones. You may also come across an Ube, but this is actually a yam.

Purple Okinawan is named after where it was developed – in the Southern Okinawa Islands of Japan. It has been part of the Okinawan diet for centuries, and thought to contribute to the long life expectancy of the islanders. The Hawaiian purple potato was the result of this purple sweet potato being introduced to this second archipelago by Japanese plantation workers. It is smoky and sweet with floral notes, with light purple flesh concealed within a pale skin, and is one of the driest of all the sweet purple tubers. 

Stokes sweet potatoes are widely available in the US. They have a purple skin, deep purple flesh and a slightly sweet and floral flavor. This variety is ideal for baking. It was developed by a farmer in North Carolina, who first received some of the purple potatoes as a gift. 

After propagating, the Stokes variety was patented. These Stokes sweet potatoes are drier and denser than the average orange sweet potato, but not as much as the Okinawan.

Ube are also similar to sweet potatoes in terms of nutritional content. They are growing in popularity in the US, and are often used in Asian desserts too.

Health Benefits

The purple pigment gives away the antioxidant content of this purple tuber. They are also rich in potassium, vitamin C, beta carotene and dietary fiber, and have a low glycemic index too.

Purple sweet potatoes are good for diabetics, reducing the risk of heart disease and hypertension, boosting immunity and brain function, promoting eye and digestive health, and can even help guard against cancer. 

Where to Buy Purple Sweet Potatoes

Okinawan sweet potatoes can be bought all year round, while the Stokes variety can be bought between late August and late spring. You can buy both at food markets, online, and sometimes in grocery stores. Purple sweet potatoes are normally sold by weight. 

You may also be able to grow your own purple sweet potatoes. A climate like Okinawa’s, or Hawaii’s is required, and it’s not always easy to get the seed potatoes you need. Stokes purple is more suited to the climate of the US mainland. 

If you want to try a specific sort of sweet potato, try a farmer’s market, as they will know exactly which crop they have been growing. 

How to Cook Purple Sweet Potatoes

Purple sweet potatoes can be used in place of regular sweet potatoes, though you may need to cook them for longer. You can also cook and eat orange, white and purple varieties together. The purple ones have a different taste, though, with a creamier, richer flavor than other types. 

Our family loves using purple sweet potatoes in recipes because the end result is more colorful, fun and appealing versus using regular ones.

A purple sweet potato can be baked, roasted, boiled or steamed. It can also be mashed after cooking. But don’t use them in a recipe that includes baking soda, as this may cause the potato’s flesh to turn green!

Before cooking, scrub each potato under cold running water and remove any imperfections with a sharp knife. It’s worth leaving the skin in place, as this is packed with fiber and also helps to preserve the nutritional value within. Baking is also the best way to retain anthocyanin and antioxidant levels, according to studies.

Roasted

Roasted purple sweet potatoes are ideal served as a side, in a salad or as part of a main meal. Before roasting, you can cut them into wedges, fries, halves or cubes. The smaller each piece, the shorter the cooking time required. For roasting, seek out larger, blemish-free potatoes that are evenly shaped. 

You can season the potatoes with salt, pepper, garlic or other flavors before cooking. Don’t peel them if possible, to preserve the nutritional value, though they may need a good scrub before being roasted. 

Baked

You can bake a purple sweet potato in several ways. Cook each one whole, or slice it in half and stuff it before placing in the oven. You can even use it in sweet desserts, such as my purple sweet potato pie, due to the mild flavor. 

A baked purple sweet potato makes a tasty, nutritious side dish during any season. You can add all kinds of toppings too. Or just add butter, and sprinkle on some salt and pepper. 

You can find a recipe for making perfect baked purple sweet potatoes below. 

Purple sweet potatoes are perfect for desserts too, and add natural color to each dish they’re used in. 

Boiled

I usually boil purple sweet potatoes, either for soup or for mashed potato. Boiling sweet potatoes in water requires no oil, and will result in soft flesh if they’re cooked for long enough. This also takes less time than baking. 

For the best results, cut the potatoes into evenly sized pieces. Don’t worry if the water goes purple or blue, as this is to be expected. 

You can also make a nutritious and vibrantly coloured soup with boiled purple sweet potatoes. After boiling, use a blender to create a creamy, colorful and nutritious soup.

Steamed

Purple sweet potatoes can also be steamed. This retains more nutrients than boiling. Steaming also reflects the naturally sweet flavor and creamy texture perfectly. 

Cubed purple sweet potatoes take about 10 to 15 minutes to steam, or for whole ones test them for softness after 25 to 35 minutes. Allow them to rest, with the lid on the pan, for about 5 minutes after turning off the heat.

Sweet potatoes can be steamed in a steamer basket over a saucepan, in a multi-cooker, in the microwave, or in a pressure cooker or rice cooker. If using the microwave, make holes with a fork all over so that excess moisture can be released.

Steamed purple sweet potatoes are very tender, and ideal when loaded up with toppings. 

Instant Pot

Cooking your purple sweet potatoes in an instant pot is a great way to prepare them – without the need to monitor them during cooking.

You can cook sweet potatoes whole, or cubed if you plan to mash them after that. 

For whole ones, use this method to determine the cooking time you need. Measure the width of the potato at the thickest section.

Under 2 inches in width: 15 minutes’ cooking time
2-3 inches: 23 minutes’ cooking time
Larger than 3 inches: 30 minutes’ cooking time

Special thanks to Garlic Head for supplying this method. Don’t forget to put a cup of water and a trivet into an Instant Pot before putting your potatoes inside. Once the cooking time is over, you must also allow the pressure to release naturally for 10 minutes.

When your sweet potatoes are ready, cut them open and stuff with your favorite toppings for serving.

For cubed potatoes, also add water and cook for about 12 minutes, once again letting the pressure release naturally for 10 minutes afterwards.

Air Fried

The air fryer cooks purple sweet potatoes perfectly. You can make roast potatoes, fries or baked potatoes in this way.

For fries, cook at 400 to 425°F for 20-25 minutes, after tossing with olive oil and seasonings.

For whole potatoes, rub with oil and air fry on 400°F for 35-40 minutes, or until they are soft.

Microwaved

You can even cook purple sweet potatoes in a microwave. Simply scrub them well with a vegetable brush under cool running water, pierce the skin with a fork, and microwave in an inch of water for 5 to 10 minutes. If they are not done, continue cooking until the center is soft.

Storage

Unwashed purple sweet potatoes will keep for up to two weeks when stored in a cool, dry place. Don’t wash them until you’re about to cook them, as this can result in rot and mold. Avoid plastic bags, or storing them in the fridge. 

Placing any potato that isn’t sprouting in a woven basket allows air to circulate freely. Purple sweet potatoes can be stored with other tubers, but not with alliums like garlic or onions.

Once they’re cooked, purple sweet potatoes will keep for several hours at room temperature, or up to five days when refrigerated in an airtight container. You can freeze cooked ones, but don’t freeze them when they’re raw.

Before freezing, boil, roast or microwave them. Mash with a squeeze of lemon before storing in heavy-duty freezer bags or airtight containers. They will then keep for up to six months.