How Long to Bake a Sweet Potato at 400 F

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Although it's possible to quickly zap a sweet potato in the microwave, there's nothing quite like the rich flavor and soft texture of a sweet potato freshly baked and taken from the oven. Generally, it's best to bake potatoes (both sweet and standard) at 400° F, but many home cooks are left wondering how long it'll take to complete their favorite side dish.

When baking sweet potatoes at 400° F, cook for 45 minutes to an hour. This will produce a sweet potato that's soft on the inside with slightly crispy skin. If you're looking for an even softer interior, you can extend the cooking time to 60-70 minutes. Conversely, if you prefer your sweet potatoes on the firmer side, you can shorten the cooking time to just 35-40 minutes.

To learn more about baking sweet potatoes, continue reading below. We'll explain everything you need to know about these delicious spudsy delights, how to prepare them, and what will affect the cooking time. Discover a few ways to alter the cooking process and enjoy a sweet potato with your next meal.

Why Should You Bake Sweet Potatoes at 400° F?

If you've ever tried to cut into a raw sweet potato, you know that the interior is hard and dense, oftentimes more so than a standard potato. This is due to the high starch and sugar content found within the sweet potato.

When these carbohydrates are exposed to high heat, they break down and convert into simple sugars. This process is known as caramelization, and it gives sweet potatoes their characteristic soft, sweet, and fluffy texture.

The ideal temperature for caramelization is between 320° F and 356° F, but most home ovens max out at 400° F. This is why 400° F is generally accepted as the best temperature for baking sweet potatoes. At this temperature, the sugars will caramelize without burning the exterior of the potato and produce a rich, delicious side dish.

Can You Cook Sweet Potatoes at a Lower Temperature?

Technically, yes. You can cook sweet potatoes at temperatures as low as 325° F, but this will significantly lengthen the cooking time. Potatoes cooked at a lower temperature will take upwards of an hour and a half to reach the desired level of tenderness.

Additionally, sweet potatoes cooked at a lower temperature are more likely to retain moisture. This can make them gummy or mushy rather than fluffy and soft. If you do decide to cook your sweet potatoes at a lower temperature, we recommend checking on them frequently and removing them from the oven as soon as they reach the desired level of doneness.

Is it Safe to Cook Sweet Potatoes at a Lower Temperature?

Unlike meat, sweet potatoes are not susceptible to bacterial growth. This means that you don't have to worry about cooking them to a specific internal temperature in order to kill any harmful microbes. With that said, sweet potatoes are still perishable foods and should be treated as such.

If you're planning to bake sweet potatoes, be sure to wash the exterior to clear away any residual dirt or fertilizer. Also, check the outside of the potato for any signs of blight or fungal growth. If infected, you'll notice blackened soft spots or lumps of mold. Throw these potatoes away and purchase fresh, clean replacements.

The Size of the Potato Can Affect Cooking Time

It's important to remember that the size of the potato will play a role in how long it takes to cook. Smaller sweet potatoes will obviously cook faster than larger ones since the heat of the oven can more easily penetrate into the flesh. Therefore, it's important to adjust the cooking time accordingly.

As a general rule, you can follow the table below to perfectly cook your sweet potatoes.

	Potato Weight	Baking Time
Small	Under 6 ounces	35 to 40 minutes
Medium	6 to 8 ounces	45 to 50 minutes
Large	Over 8 ounces	55+ minutes

If you are unsure about the size of your sweet potato, you can always insert a toothpick or cake tester into the potato after 35 minutes to test for firmness.

Using Foil—Does it Increase or Decrease the Cooking Time?

Another common question home cooks often have is whether or not to wrap their sweet potatoes in foil prior to baking. The answer to this question is somewhat complicated. On the one hand, wrapping the potato in foil will create a steam pocket which can speed up the cooking process. This is because the steam will help to break down the starch molecules, making them easier to caramelize.

On the other hand, wrapping the potato in foil will also prevent the exterior from browning and crisping. This may be desirable if you're looking for an ultra-soft sweet potato, but it's worth noting that the skin of the potato is packed with nutrients.

If you do decide to wrap your sweet potatoes in foil, be sure to poke a few holes in the top to allow steam to escape. This will help to prevent the foil from becoming soggy and sticking to the potato.

The Safety of Baking With Aluminum Foil

In recent years, there have been concerns that cooking with aluminum foil can cause the metal to leach into your foods. While it's true that aluminum foil is not considered a health food, the amount of aluminum that actually transfers into your food is negligible.

According to a study published in the Journal of Trace Elements in Medicine and Biology, cooking with aluminum foil for two hours at temperatures up to 350° F was shown to transfer less than 0.1% of the aluminum into food.

Another study published in the International Journal of Electrochemical Science found that the amount of aluminum leached from foil was even lower when it was used to wrap acidic foods, such as lemons or tomatoes. So, while cooking with aluminum foil may have some people worried, it's not likely to cause any harm either.

oven baked sweet potato in aluminum foil

Other Ways to Decrease the Cooking Time for a Sweet Potato

If you find yourself in a bind and need to cook your sweet potatoes faster, there are a few methods you can use to speed up the process:

One popular method is to precook the potatoes in the microwave for 5 to 7 minutes prior to baking. This will help to soften the flesh, making it easier for the heat of the oven to penetrate the potato. Just be sure to use a fork to poke a few holes in the potato before microwaving to prevent it from exploding.
Another method is to slice the potatoes into thin wedges or rounds prior to baking. This will also help the heat to reach the center of the potato more quickly. Just be sure to keep an eye on the potatoes while they're in the oven so they don't overcook and become dry.

Of course, microwaving your potatoes can cause them to develop a wrinkly, mushy texture rather than a rich, creamy feel. Additionally, if you slice your sweet potatoes, you won't be able to enjoy the pleasantly mashed interior of a baked potato.

Cooking a Frozen Sweet Potato

Although sweet potatoes are available year-round, they're actually in season from late September through early December. This is when they're at the peak of freshness and flavor. If you want to enjoy sweet potatoes during the off-season, your best bet is to purchase them frozen. Fortunately, you can cook frozen sweet potatoes without thawing them first.

Simply place the potatoes on a baking sheet and bake at 300° F for 100 to 120 minutes, or until tender. You may need to increase the cooking time by 10 to 15 minutes if you're baking multiple potatoes at once. Just be sure to keep an eye on the potatoes while they're in the oven, so they don't overcook and become dry.

Storing Fresh Sweet Potatoes

If you're lucky enough to find fresh sweet potatoes during the peak season, you'll want to store them properly to extend their shelf life. Sweet potatoes are best stored in a cool, dark, and dry place, such as a pantry or cupboard. Ideally, you should keep them in a paper bag rather than a plastic bag since this will allow them to breathe.

If you must store them in a plastic bag, be sure to poke a few holes in the bag to allow for ventilation. You should also avoid storing sweet potatoes in the fridge since this can cause them to develop a hard, waxy texture. If you have leftover cooked sweet potatoes, you can store them in the fridge for up to four days.

My Personal Tips for Baking a Sweet Potato

Before we get into a specific recipe, we wanted to share a few more tips to help you make the best baked sweet potatoes possible. Check them out below and consider applying them to your cooking method the next time you make a baked sweet potato:

When baking sweet potatoes, use ones that are on the larger side. If you can't find any decent-sized sweet potatoes, use 2 or 3 smaller ones. By using larger potatoes, you can guarantee that you get a decent portion size, even if the potatoes shrink during the cooking process.
When you're prepping the sweet potatoes, make sure to wash them well and pat them dry. Once the sweet potatoes are dry, you'll want to poke a few holes in them so steam can escape. To make things easier, you can poke the holes in the sweet potatoes with a fork before baking them.
When baking sweet potatoes, you can bake them right on a baking sheet or on a rack. If you're baking them on a rack, you'll want to place a baking sheet under the rack to catch any of the juices that drip off the sweet potatoes while they're baking.
If you like your sweet potatoes to have crispier skins, you can always bake them for a little longer (around 55 minutes).

Frequently Asked Questions

Is it better to bake sweet potatoes in the oven or microwave?

It's generally accepted that oven-baked sweet potatoes are superior to microwaved sweet potatoes. This is because the high heat of the oven helps to caramelize the sugars in the potato, giving them a rich, sweet, and fluffy texture. Microwaving sweet potatoes can cause them to develop a wrinkly, mushy texture.

How do you keep sweet potatoes from drying out in the oven?

There are a few ways to prevent your sweet potatoes from drying out in the oven. First, brush them with olive oil or melted butter before baking. This will help to create a barrier between the potato and the dry heat of the oven. You can also wrap the potatoes in foil before baking. This will create a steam pocket which will help to keep the potatoes moist.

Can you overcook a sweet potato?

Yes, you can overcook a sweet potato. If you cook the potato for too long, the exterior will become dry, and the interior will become mushy. To prevent this, be sure to check on the potato regularly and remove it from the oven as soon as it's tender.

A Fool-Proof Recipe for Baked Sweet Potatoes

Now that we've gone over some general tips, it's time to get into a specific recipe. The recipe below is for a basic baked sweet potato but feel free to add your favorite toppings, such as butter, cinnamon, or brown sugar.