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Sweet Potatoes White Ooze – What Is It?

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Sweet potatoes are a fantastic staple to have in your pantry at all times. They’re delicious, versatile, and packed with nutrition – what’s not to love?

However, the sight of oozing white stuff coming out of your potato might be enough to turn you off of the vegetable.

Hopefully, you’ll be willing to give them another shot, however, because not only is it normal, it may even be a sign of an extra sweet sweet potato!

What is the white ooze in sweet potatoes? The white substance that sometimes seeps out of sliced sweet potatoes is a completely normal sap, a mixture of sugar and starch. It is not harmful in any way and is completely safe to eat. 

If you’d like to learn more about the white ooze common in sweet potatoes, keep reading.

We’ll also share some other common worries about sweet potatoes and allow you to eat in peace, knowing what is truly concerning and what is just nature being a little weird.

What Is the White Residue in Sweet Potatoes?

Many vegetables will leak a latex-like residue when they’re cut. Squash, chayote, and sweet potatoes are among the most common.

There are many speculations as to why some potatoes leak sap while others don’t. Some of the most common theories include:

  1. The sweeter the potato, the more likely it is to have white ooze because it is the sugars that are leaching out.
  2. Organic sweet potatoes are more likely to have milky residue because something in the process of growing them in mass quantities reduces the milky starch. Whether it is genetically modifying the seeds, using different fertilizers and pesticides, or another factor is unclear.
  3. The fresher the sweet potato is, the more likely it is to leak white ooze. This also makes sense because, as sweet potatoes age, they start to dry out. This makes them much less likely to leak any type of liquid. 

So, not only is white sap safe and no cause for concern, but it also may be a sign that your sweet potato is super sweet, organic, extra fresh, or all three!

Sweet Potato White Spots

Depending on how you are preparing your sweet potato, you may never see any white sap, or you may notice it in different ways. 

A baked sweet potato that is scrubbed but not cut in any way probably won’t have any signs of liquid starch.

If you peel a sweet potato whole, however, you may notice some of the milkiness creating a thin sheen along the surface of your potato. You can simply wash it off before cooking, but it is fine to eat.

If you slice a sweet potato in half and open it up, you may notice tiny white spots appearing, speckling through the interior of your potato.

This, again, is simply the starch and sugar finding their way through the flesh of the potato through any minuscule hole they can escape out of.

Whether the white spots are small and distributed throughout the potato, or larger and concentrated in certain areas, the milky sap is not harmful and can be rinsed off easily, though it will be sticky to touch.

Once cooked, the starch is not sticky and you will not notice it in your potatoes in any way.

Sweet Potato White Flesh

If you have purchased a sweet potato that has white flesh inside, rather than vibrant orange flesh with white spots or white ooze, you may have accidentally bought yourself a yam.

In most of North America, yams are inaccurately labeled. What are often called yams are actually a type of soft sweet potato.

Proper yams typically have brown skin and white or purple flesh, whereas sweet potatoes have orange flesh. If your sweet potato is white, you probably have a yam.

Yams and sweet potatoes are very similar in taste and texture, though yams are slightly less sweet and have a drier texture.

How to Tell If a Sweet Potato Is Bad 

Sweet potatoes last a long time in the right conditions, but even these root vegetables will go bad over time. There are different types of decay to watch out for, each with unique signs indicating the poor quality of your sweet potato.

The most glaringly obvious sign that your sweet potato has gone bad is wrinkled, shriveled skin. If your potato has started to shrivel, it’s best to discard it and not eat it. 

Some of the other most common problems to deal with in terms of sweet potatoes are mold, pithiness or holes in your potatoes, and/or dried out insides.


Sweet potatoes often develop dark spots, which don’t necessarily mean your potato has gone bad.

You should only be concerned if, in addition to discoloration, you notice visible mold.

Mold on sweet potatoes may be fuzzy and white, green, or blue around holes or cuts, or it may look and smell rotten underneath the skin of your sweet potatoes.

When potatoes of any variety go rotten, you will smell them. Do not eat potatoes that have signs of mold or you can get sick. 


If you’ve ever picked up a sweet potato that you wanted to prepare for dinner and noticed that it had a sponginess to it, you may have discovered a pithy potato. If you sliced it open to reveal holes inside, you would be certain.

Holes in sweet potatoes can develop when they’re stored somewhere that is too warm for their liking. Sweet potatoes are picky and they don’t do well in areas that are either too hot or too cold.

Pithy potatoes are safe to eat. However, the texture is compromised and the flavor is usually less enjoyable than tubers that have been stored under more ideal conditions.

A few small holes will be fine to eat, but a very pithy potato should be discarded simply because it won’t taste great.

Dried Out

Dry spots either on the inside or outside of your sweet potato are indications of an old potato that has lived past its prime. 

Small dry spots around the surface can be removed and you shouldn’t notice too much of a difference in flavor or texture.

But if you cut open a raw sweet potato and find that it is dry inside, that will affect how your potato feels, primarily, but it may also impact the flavor.

If there is only a little bit of dryness, you may be able to boil and mash the potato without anyone being the wiser, but it’s better to discard potatoes that have too many dry areas inside.

Growing Roots

If you start to notice that small sprouts or roots are forming in the eyes of your sweet potato, you should take this as a sign that the quality is starting to deteriorate.

They are still safe to eat and will taste fine, but the longer the roots grow, the less desirable the sweet potato will become. 

When you’re choosing from a large selection of sweet potatoes in your pantry, always use the ones that look like they’re sprouting first. Just trim off the growing roots and peel or prepare as normal.

Related Questions

How Long Do Sweet Potatoes Last?

Fresh, healthy sweet potatoes will last in your pantry for up to 3 weeks before starting to deteriorate, depending on the storage conditions. 

To keep your sweet potatoes healthy for as long as possible, store them in a cool, – but not cold – dry location away from direct light.

Sweet potatoes do not like fluctuating temperatures or extremes of either heat or coldness. They are also much more likely to spoil if they’re exposed to any moisture, so make sure they’re dry at all times.

Once you’ve cut your sweet potatoes, you will want to use them within a few days. Store them in water to prevent them from oxidizing and make sure they are well sealed, either in an airtight container or zip bag.

Cooking sweet potatoes can also be stored for a few days in your fridge. Try to finish them within 3 days.

You can also freeze sweet potatoes and sweet potato fries and casserole. It’s better to freeze them after they’ve been cooked. They will stay in good condition for 1–3 months if frozen carefully.

Why Does My Sweet Potato Taste Like Soap?

Humans have the ability to taste 5 different flavors: sweet, salty, sour, bitter, and umami.

Some people are particularly sensitive to bitter flavors, known as supertasters, and many others simply dislike the taste of bitter foods. If you find that sweet potatoes taste like soap or perfume, the reality is they are probably bitter.

Sweet potatoes are not meant to be bitter and this could be a sign that your potatoes had begun to rot or were grown in poor conditions.

Either way, if your sweet potatoes are bitter, you may want to avoid eating them.

Is a Hollow Heart Potato Safe to Eat?

Hollow hearts in potatoes is similar to pithy potatoes but more severe. Rather than being caused by poor storage conditions, hollow hearts are usually the result of poor growing conditions.

If you cut open a sweet potato and find that is it hollow in the center, or has a large brown, bruised area in the middle, you have a hollow heart sweet potato. 

Unfortunately, you will have a much smaller amount of potato than you expected. Fortunately, the flavor and texture should not be compromised, so you can eat the rest of the potato safely.

Up Next: Can You Freeze Sweet Potato Casserole?

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