Every November, North American kitchens turn out the same dish: orange sweet potatoes, mashed, sweetened and buried under toasted marshmallows. It is dessert dressed up as a side, and plenty of people will defend it to the last spoonful.
Korea has a different idea of what a sweet potato wants to be. Nothing gets added. A vendor pulls a whole one out of a hot metal drum and hands it over with the skin still on, and that is the entire recipe.
 |
| Gungoguma is usually eaten plain, straight from the bag while it is still hot. |
The snack is called gungoguma (군고구마), which simply means roasted sweet potato, and it belongs to the cold half of the year. Earlier this year it also turned up in an odd place: New York office lunches. Both stories are worth knowing before you buy your first one.
The Drum Can and the Cold Season
Gungoguma is a whole sweet potato roasted in a metal drum and sold hot from the street, traditionally from late autumn into winter. That is how reference sources describe it, and the same sources note the snack is popular in both North and South Korea.
The idea is not Korean alone. The New York Post notes that sweet potatoes are a winter treat across Japan, Korea and China, and Japan has its own roasted version, yaki-imo, including a stone-roasted style. Korea's signature is the drum can.
The vendors even come with a uniform. They often wear fur-flapped ushanka hats, so closely tied to the trade that the hat is sometimes called a roasted sweet potato vendor hat.
The nearest North American cousin is the roasted chestnut cart on a New York corner in December: something hot, plain and handed over in a bag, which only makes sense when you can see your breath. The difference is scale. A chestnut is a nibble, while a gungoguma is a small meal that warms your hands first.
Outside winter, the food does not disappear. It is now eaten in summer as ice cream and smoothies, and in South Korea the potatoes are also dried into gungoguma-mallaengi or frozen and eaten as ice-gungoguma. Those are the details reference sources note, and they suggest a food that keeps finding new jobs.
Moist or Dry: Choosing Your Texture
The first thing to know about picking a gungoguma is that the flesh comes in two main personalities. Korean sources say any goguma can be roasted, but softer, moister types such as hobak-goguma (pumpkin sweet potato) are preferred over floury bam-goguma (chestnut sweet potato).
A 2024 report in Nongmin Sinmun, a Korean farm newspaper, drawing on Rural Development Administration data, sorts Korean sweet potatoes into three informal groups. Bam-goguma turn dry and crumbly when cooked, mul-goguma (water sweet potatoes) are very moist, and hobak-goguma land in between, with moderate moisture and a sweet pumpkin flavor. The paper is careful to say these are convenient names and not exact cultivar names.
It also published sugar readings in Brix, a standard measure of sugar content. One pumpkin-type cultivar, Hopungmi, measured 26.9 Brix steamed and 32.7 roasted. That is a single cultivar in a single report, so it proves nothing broad, but it fits what roasting is supposed to do: drive off water and concentrate the sweetness.
Descriptions in English do not always line up with this. A 2022 piece in The Takeout described the purple-skinned Korean sweet potatoes sold in American Asian markets as drier than orange-fleshed ones, with a chestnut-like flavor. That sounds closer to the bam type than the moist type Korean sources favor for roasting. The New York Post, for its part, describes the Korean sweet potatoes at H Mart as having creamier, lighter flesh than the American orange kind. Rather than guess which one you are holding, taste before you assume, and ask if the seller knows.
How to Pick a Good One
A good gungoguma starts with size and shape: the Korean farm report suggests about 100 to 200 grams per potato (roughly 3.5 to 7 ounces), an even shape and a vivid skin color. An oversized potato may look like better value, but that guidance points to the smaller ones.
Buying One (Quick Guide)
Look for a medium potato that is even in shape, with clear skin color and no obvious damage. Choose by texture too. If you like a soft, almost custardy middle, go for the moist, pumpkin-type kind. If you prefer something that eats like a chestnut, pick a drier one.
In the United States, Asian markets are the easy route. The Takeout writer noted that a local H Mart kept a heated display of ready-to-eat potatoes in 2022, so call ahead because stores differ. In Manhattan, a New York Post report from January 2026 put an H Mart two-pack at about $6 to $7.
Roasting One at Home (Quick Guide)
The Takeout's method is simple: poke holes in the potato with a fork, roast at 400°F for about an hour, and check with a knife, which should slide in easily. Once it is cool enough to handle, the skin peels off in easy strips. Timing depends on the size of the potato, so use the knife test and not the clock.
Skin is a matter of taste. One lifestyle expert quoted in the New York Post said, "I love the skin. That's glorious." Others peel theirs, and either choice works.
One Honest Caveat
Of the cooking methods in the Korean farm report, roasting scores worst for blood sugar. The same report cited glycemic index figures of 61 for raw, 80 for roasted and 45 for steamed or boiled sweet potato. If you track blood sugar, steaming is the gentler option, and a doctor can tell you more than a food blog can.
Why Manhattan Offices Are Buying Them
The short answer from the press is lunch prices. In January 2026, the New York Post reported that Midtown office workers were turning to cheap roasted sweet potatoes as restaurant lunches got more expensive, and the story was picked up by other outlets within days.
The Post cited a handful of sellers. Julie & Co., a Koreatown stall on West 32nd Street, charged $7.99 per pound, which works out to roughly $2 to $3 a potato. At Rockefeller Center, Duke Eatery sold them for $6.99 per pound and often ran out during the lunch rush. Miznon, also at Rockefeller Center, charged $5 for one or $9 for two, honey-roasted and served with sour cream.
The Post set that against the usual office fare. A Julie potato cost about a third of a small order of Five Guys fries, and an H Mart two-pack came to less than half a typical Sweetgreen bowl. Another publication, When In Your State, reported carts near Penn Station and Koreatown with long lines of workers and sellouts near Radio City Music Hall during lunch.
Take those details with the right amount of salt. They are press reports built on a handful of vendors, the prices date from December 2025 and January 2026, and nobody has counted the lines. The driver in the reporting is price, so a headline calling this the next big K-food hit stretches past what the Post actually said.
Even so, the Post story does contain one useful line from the Koreatown stall's owner, who said, "Korean people really love to roast it." Seoul and Manhattan reach the same potato for different reasons. In Seoul it is a seasonal snack that arrives with the cold. In Midtown it is a cheap way to skip an expensive lunch.
The Post also gathered a few fans. Instagrammer Courtney Cook called the potato "so wholesome" and said it "really gives me energy." Those are testimonials from social media personalities, so read them as enthusiasm, not evidence.
 |
| Gungoguma is traditionally roasted in a metal drum and sold hot from late autumn into winter. |
Plain, Honey-Roasted or Marshmallow
The Miznon version, with honey and sour cream, is a good reminder that the Korean method is only one of several. The Post described the typical New York office worker as eating the potato plain, without butter or salt, and The Takeout says goguma are usually eaten plain as a hot street snack. Americans, as that writer put it, tend to add butter, seasonings or condiments.
That plainness is the whole point, because a well-roasted potato already carries its own sweetness. Food blogger Mr. Spice Guy Eats told the Post a roasted one "tastes like marshmallow." Whether that sounds appealing or alarming probably depends on how you feel about the Thanksgiving casserole.
Set the two traditions side by side and the difference is easy to see. The Thanksgiving casserole adds its sweetness from outside, with sugar and a marshmallow crown. Gungoguma relies on what roasting does to the potato itself, which is why the Brix numbers above matter and why a plain potato has nowhere to hide. That makes the choosing step in this guide more than a formality.
 |
| A hot roasted sweet potato and a warm mug make a simple winter afternoon snack. |
Anyone who wants to test the claim does not need a plane ticket. A medium potato, a fork, a hot oven and an hour will get you most of the way there, or you can look for a ready-made one at an Asian market. Peel it in strips, eat it plain, and see whether the marshmallow line holds up before the real marshmallows come out.
Explore more Insights into Korean Lifestyle:
culture / ktoday / market / street food / vendorsSep 24, 2026.webp)
comfort-food / food / korean-cooking / pillar / recipe / slow-cooked-korean-dishesSep 1, 2026.webp)
bibimbap / dolsot-bibimbap / food / korean-rice-bowl / recipeSep 1, 2026
From K-Media and Food to practical Korean used in daily life and K-Dramas.
© FRANVIA. ALL RIGHTS RESERVED.
.webp)
.webp)
.webp)
.webp&description=Korean Roasted Sweet Potato: Why It Rules Seoul Winters){kind=link}