Black Sesame Soup (Zhi Ma Hu), a Cantonese Sweet Soup

Black sesame soup is a warm Cantonese dessert: toasted black sesame seeds, ground with soaked rice and water, then simmered until thick, glossy and jet black. It tastes nutty and roasted, and only gently sweet. One pot serves 4. It needs 25 minutes at the stove, once the rice has soaked for 3 hours.

What black sesame soup is

Black sesame soup is a tong sui, one of the sweet soups that end a Cantonese meal. Cantonese speakers call it zi maa wu, and Mandarin speakers zhi ma hu. The name means sesame paste, and that describes it well. It pours like warm honey, and you eat it hot, with a spoon.

Tong sui means sugar water. The MICHELIN Guide defines it as a sweet, warm soup or custard served as a dessert at the end of a Cantonese meal. Dessert shops sell this one beside walnut and almond soups, and some will pour two into one bowl.

Only four things go into the pot: black sesame seeds, rice, water and sugar. The seeds bring the flavor and the color, and the rice thickens the soup. It holds no dairy and no eggs.

A Hong Kong dessert shop classic

In Hong Kong, tong sui has shops of its own. Zolima CityMag traces the oldest surviving one, Yuen Kee, to Hollywood Road in 1885. Black sesame sweet soup was already on its menu, next to steamed milk pudding.

The soup still draws a crowd. The MICHELIN Guide gives a Bib Gourmand to Kai Kai, which began as a street stall in 1979, and its inspectors suggest the black sesame soup. At Heartwarming, another Bib Gourmand shop, two stone mills grind black sesame seeds at the door.

Zolima also visited Tei Mou Koon, a shop in Kowloon City. In winter it sells 100 to 200 bowls a day of this soup and its steamed milk pudding. The cook toasts the seeds in a giant wok until they pop, then grinds them with water. He cooks that sesame milk with rice milk and white sugar. This recipe follows the same method, scaled down to a blender and a saucepan.

Cousins across Asia

The soup traveled. In Hội An, in central Vietnam, people call it xí mà and eat it for breakfast. VietNamNet describes it as a meeting of Vietnamese, Chinese and Japanese cooking. It credits a local man, Ngô Thiểu, born in 1915, with creating the town’s version. His children carry on the trade.

Korea has heugimja-juk, a porridge of black sesame and rice. It uses twice as much rice as sesame, and cooks season it with salt, as the recipe at Kimchimari shows. In Japan, black sesame is kuro goma, a classic flavor in sweets and in ice cream.

Why black sesame is trending now

Black sesame is having its year. In June 2026, Google’s Summergeist report said people were searching for black sesame more than ever, above all for desserts. Its trends page listed black sesame ice cream and black sesame cookies as breakout searches. Google uses the word breakout for a search term that has grown by more than 5,000%.

Yelp saw it coming. Its 2026 food and drink forecast, published in November 2025, named black sesame a standout flavor. Searches for black sesame desserts rose 21%, and searches for black sesame matcha rose 147%. Yelp compared September 2024 through August 2025 with the 12 months before.

Others followed. In January 2026, NPR listed black sesame among the flavors expected to rise this year. In February, Country & Town House asked whether it was the new matcha. The UK bakery chain GAIL’s was preparing an iced black sesame matcha latte for its spring menu.

Lattes, cookies and ice cream are new uses for the seed. The sweet soup is the old one, and the plainest way to taste what the fuss is about.

Does black sesame keep hair dark?

Many Chinese families say so. Zolima CityMag records the popular belief that black sesame keeps hair from going grey. In 2026 the idea spread on social media too.

The evidence is thin. In July 2026, Woman & Home put the claim to Dr Magnus Lynch, a consultant dermatologist. He said the seeds hold healthy minerals and antioxidants. He also said no scientific evidence shows that they stop hair turning grey. Eat the soup because it tastes good.

What you need: seeds, rice and a blender

Black sesame seeds

Buy raw, whole black sesame seeds. Asian grocers sell them in bags, and many supermarkets stock them near the spices. Black sesame is a variety of its own, sold with its hull on. A 2022 review in Nutrients found that black seeds hold the most sesamin and total lignans of any sesame.

The hull shapes the taste. The Hong Kong Cookery finds black sesame more intense than white, and slightly bitter. That bitter edge is why the soup needs sugar, and why toasting must stay gentle.

The hull also holds the minerals. By USDA figures, 100 g of whole sesame seeds has 573 calories, 11.8 g of fiber and 975 mg of calcium. Hulled seeds have only 60 mg of calcium. A 2014 review cautions that oxalic acid in the seed coat binds much of that calcium. Do not count on the soup for it.

Ready-toasted seeds work too. Warm them in the pan for 2 to 3 minutes, just until fragrant, as Omnivore’s Cookbook advises.

Rice, the thickener

Rice gives the soup its body. This recipe uses 3 tablespoons (35 g) of plain white rice, jasmine or long-grain, soaked until soft. Soaked rice blends to a smooth rice milk, and its starch thickens the pot as it cooks.

Glutinous rice works in the same amount, for a slightly silkier soup. Keep the rice modest. Published recipes run from 5 parts sesame to 1 part rice, all the way to equal parts. More rice turns the soup into porridge.

Sugar

Cantonese cooks favor rock sugar. The Hong Kong Cookery describes it as less sweet than granulated sugar, with a mellow sweetness. Granulated sugar works just as well by weight.

Start with ¼ cup (50 g), which makes a lightly sweet soup. Add up to 2 tablespoons (25 g) more at the end if you like.

A blender and a fine sieve

A high-speed blender grinds the seeds fine enough to skip straining. Omnivore’s Cookbook gives 1 minute in a Vitamix, or up to 3 minutes in a regular blender. With a regular blender, strain the liquid through a fine-mesh sieve.

You also need a wide skillet, a 2- to 3-quart (2 to 3 liter) saucepan and a wooden spoon.

How to make black sesame soup at home

Soak the rice

Rinse the rice, cover it with cold water and leave it for at least 3 hours. TASTE soaks its rice for 3 to 12 hours and gives a simple test. A soaked grain should break apart easily between your fingers. For a longer soak, put the bowl in the refrigerator overnight.

Toast the seeds gently

Toasting wakes up the sesame. Spread the seeds in a dry skillet over medium-low heat and stir them the whole time. Raw seeds take 6 to 10 minutes.

Black seeds do not change color, so use your other senses. The seeds smell nutty, and a few begin to pop. Daily Cooking Quest adds a third test: a toasted seed shatters when you press it between your fingers. For a cue you can see, add a pinch of white sesame seeds and stop when they turn golden.

Do not push past that point. Over-toasted sesame turns bitter, and sugar cannot hide it. Tip the seeds onto a cool plate at once, because a hot pan keeps cooking them.

Blend until smooth, then strain

Put the toasted seeds, the drained rice and 2 cups (480 ml) of water in the blender. Blend on high for 1 to 3 minutes, until the liquid looks like smooth, dark grey cream. Rub a drop between your fingers. It should feel silky, with only the finest grit.

A high-speed blender needs no sieve. Pour the liquid into the saucepan and add 2 cups (480 ml) of water.

With a regular blender, pour the liquid through a fine-mesh sieve into the saucepan. Return what the sieve catches to the blender with 1 cup (240 ml) of fresh water, and blend for 1 minute more. Strain it again, then add 1 cup (240 ml) of water to the pan. TASTE repeats this step until barely any bits remain.

Simmer and stir

Add the sugar and set the pan over medium heat. Bring it to a boil, about 5 minutes, stirring all the time. The soup thickens fast as it heats. Left alone, it catches on the bottom and spits.

Lower the heat and simmer for 10 to 12 minutes, still stirring. The color deepens from grey to black, and the raw taste of the rice cooks out.

How thick should it be?

Dim Sum Central aims for a silky soup with the viscosity of honey. Dip a spoon in the pot. The soup should coat the back, and a finger drawn through it should leave a clean line.

It thickens more as it cools, so stop a little early. If it gets too thick, stir in hot water, 2 tablespoons (30 ml) at a time.

Shortcuts and variations

No time to soak: rice flour

Swap the rice for ¼ cup (35 g) of plain rice flour. Blend it with the toasted seeds and 2 cups (480 ml) of water, then cook the soup as usual. It is ready in about 35 minutes.

Black sesame powder

Pure black sesame powder skips the toasting and the blending. Christine’s Recipes uses it with rice flour, and advises a powder with no added sugar. The finer the powder, the smoother the soup.

For this pot, whisk 105 g of powder and ¼ cup (35 g) of rice flour into 4 cups (960 ml) of cold water. Add the sugar, then boil and simmer it as above.

Two soups in one bowl

Hong Kong shops sometimes serve black sesame soup beside a pale walnut soup, as Green Queen notes. People call the pair yin-yang. At home, a spoonful of coconut milk swirled on top gives the same black and white look.

With coconut milk

For a richer bowl, replace 1 cup (240 ml) of the water with coconut milk. Stir it in for the last 2 minutes of the simmer.

Serving black sesame soup after Sunday dinner

Serve the soup hot, in small bowls of about 1 cup (240 ml). In Hong Kong, a tong sui shop is where people go after a heavy dinner, as Foodie puts it. The soup suits the end of a long Sunday meal for the same reason. It is warm and light, and not very sweet.

Ladle it out after a pot of Filipino chicken adobo and rice. Its roasted taste goes well with a hojicha latte. If your table wants cake as well, bake a sticky toffee pudding.

In Hội An, people eat it in the morning. A bowl of leftover soup, warmed up, makes a fine breakfast.

Storing and reheating

Let the soup cool, then keep it in an airtight container in the refrigerator for up to 3 days. The USDA says most cooked leftovers keep 3 to 4 days. Omnivore’s Cookbook freezes the soup for up to 2 months.

It may separate or thicken as it stands. Stir it, add a splash of water and reheat it gently until steaming hot.

Sesame allergy

Sesame is a major food allergen. In the United States, the FDA has counted it as the 9th major allergen since January 1, 2023. In the UK, the Food Standards Agency lists it among the 14 allergens named in food law. Tell your guests what is in the bowl.

Calories per serving

One bowl has about 230 calories, by USDA figures. It holds 13 g of fat, 26 g of carbohydrate and 5 g of protein. An unstrained bowl has about 3 g of fiber, and a strained one has less.

Fixes for bitter, gritty or thin soup

• Bitter: the seeds toasted too long. Start again with fresh seeds, and stop at the first pops.
• Gritty: the blender ran too briefly. Blend for up to 3 minutes, then strain the liquid through a fine sieve.
• Too thin: simmer it for 3 to 5 minutes more, stirring. It also thickens as it cools.
• Too thick: stir in hot water, 2 tablespoons (30 ml) at a time.
• Grey, not black: it needs more time. The color darkens during the 10 to 12 minutes of simmering.
• Stuck to the bottom: the heat was too high, or the spoon stopped. Pour the soup into a clean pan, and leave the stuck layer behind.

Substitutes for missing ingredients and equipment

• Raw black sesame seeds: ready-toasted seeds. Warm them for 2 to 3 minutes only.
• Some of the black seeds: white sesame seeds, for up to a quarter of the weight. Zolima notes that shops mix some in, because white seeds hold more oil.
• White rice: glutinous rice in the same amount, or ¼ cup (35 g) of rice flour.
• Rock sugar: granulated sugar in the same weight, or light brown sugar.
• High-speed blender: a regular blender and a fine-mesh sieve.
• Fine-mesh sieve: a clean cotton cloth laid in a colander.
• Part of the water: 1 cup (240 ml) of coconut milk.

Frequently asked questions

What does black sesame soup taste like?

It tastes of toasted nuts, a little like tahini or peanut butter, with a faint bitter edge. It is only gently sweet. The texture is smooth and thick, like warm honey.

Does black sesame soup turn grey hair dark?

No study shows that it does. The belief is old and common in Chinese families. A dermatologist asked by Woman & Home in 2026 said there is no scientific evidence for it.

Do I have to soak the rice?

Yes, for at least 3 hours, so it blends smooth. To skip the soak, use ¼ cup (35 g) of rice flour in place of the 3 tablespoons (35 g) of rice.

Why is my black sesame soup bitter?

The seeds toasted too long or too hot. Toast them over medium-low heat for 6 to 10 minutes, and take them off the heat when they smell nutty and a few pop.

Do I need to strain it?

Not with a high-speed blender, which grinds the seeds fine in about 1 minute. With a regular blender, strain the liquid through a fine-mesh sieve and blend the solids a second time.

Can I use black sesame powder or paste?

Yes. Use 105 g of pure, unsweetened black sesame powder in place of the seeds, with ¼ cup (35 g) of rice flour. Sweetened pastes vary, so add the sugar last, to taste.

Is black sesame soup vegan and gluten-free?

This version holds only sesame seeds, rice, water, sugar and salt. It has no animal products and no grains with gluten. Sesame is a major allergen, so tell your guests.

How long does black sesame soup keep?

Up to 3 days in an airtight container in the refrigerator, or 2 months in the freezer. Stir it, add a splash of water and reheat it gently.

Is it served hot or cold?

Hot. Cantonese dessert shops serve it warm, and it suits cool autumn and winter evenings. Chilled, it sets thick, more like a pudding.