Sweet Red Bean Soup (红豆汤)

Sweet red bean soup belongs to the family of Tong Sui/糖水 (meaning sugar water literally), a dessert category for sweet treats in soup form that are popular in Cantonese food, a regional cuisine of China.

Essentially, it’s dried adzuki beans (commonly known as red beans, Hóng Dòu/红豆) cooked and mashed into a creamy soup with a nice bite of soft beans. It has an earthy, nutty, mildly sweet taste with a hint of citrusy flavor.

The Chinese names for this dessert soup include Hóng Dòu Tāng/红豆汤, Hóng Dòu Gēng/红豆羹 and Hóng Dòu Shā/红豆沙. The last name is commonly used in Hong Kong and it may cause confusion with red bean paste which shares the same name in other parts of China.

Lovely both warm and cold, it can be enjoyed at the end of a meal, or as a snack at any time of the day. It takes some time to cook it but the process is very simple and straightforward.

Top tips

Here are some helpful tips before we dive deep into the recipe details:

• Freeze the soaked beans to reduce cooking time.
• Control the blending to achieve your preferred consistency.
• Add optional ingredients to improve texture.
• Make a big batch and freeze it for later use.

Ingredients & substitutes

Here are all you need to make sweet red bean soup:

• Adzuki beans, aka red beans
• Fresh orange zest, or dried tangerine peels
• Dark brown sugar (or other sweeteners), plus a little salt
• Optional add-on: small tapioca pearls (sago)

Adzuki beans

Adzuki beans can be found in dried food sections of Chinese/Asian supermarkets. They need to be rehydrated before cooking. I sometimes also use canned ones that are already cooked. They’re a very handy alternative.

The bean-to-water ratio

If cooking on the stove, I suggest you use 1 part of dried beans with 5 parts of water (in volume). If using an instant pot (or a stovetop pressure cooker), reduce the water to 4 parts as there won’t be much evaporation.

Fresh orange zest

Traditionally, dried tangerine peels (Chén Pí/陈皮) are used to give red bean soup a hint of citrusy aroma. They are an ingredient often paired with spices for stew dishes.

If you don’t have them in the pantry, grate some orange zest to substitute. This method is more accessible, and the taste isn’t compromised.

Dark brown sugar

Rock sugar (Bīng Táng/冰糖) is traditionally called for in classic Chinese desserts (think Pear & Rock Sugar). I prefer dark brown sugar for today’s recipe for its caramel taste on top of the sweetness.

Other options include white sugar, light brown sugar, or liquid sweeteners, such as honey, golden syrup, etc. I’ve also tried sweetened condensed milk which adds a rich milky taste. You’ll also need a pinch of salt which helps to bring out the sweetness effectively.

Optional add-ons

The ingredients above are sufficient for making the basic version of red bean soup. If you’d like to go the extra mile, consider adding one more ingredient to make it even more appealing.

Popular add-ons include small tapioca pearls (sago, Xī Mǐ/西米), glutinous rice balls (without filling), lotus seeds, coconut milk, etc. My recipe uses tapioca pearls which have a bouncy, slippery texture once cooked. They help the soup to develop a creamier, smoother mouthfeel.

Cooking procedure

Step 1: Soak the beans

This process helps to reduce cooking time. Make sure you use plenty of water as the beans will swell up. Leave them to soak overnight or for at least 4 hours.

🛎 A speedy trick: Like the fast method I use for cooking congee, you may freeze rehydrated beans (drain off the water). The water inside the beans will expand while freezing forcing the beans to break. This will help shorten the cooking time required in the next step.

Step 2: Cook the beans

Drain off the soaking water then put the beans and orange zest in a pot/large sauce. Add clean water, about 5 times the volume of the dried beans. Bring to a full boil then turn the heat down to the lowest. Cover with a lid and let simmer for 1½ hours.

The cooked beans are still in their original shape but when pressed between fingertips, they should be mashed very easily.

🛎 Instant pot method: Alternatively, use an instant pot (or a stovetop pressure cooker) to cook the beans in water which is 4 times the volume of dried beans. It takes 25 minutes on high pressure. Allow the pressure to release naturally.

Step 3: Blend the beans

This step breaks the beans. I use an immersion blender for convenience. It can also be done by transferring the beans and the cooking liquid to a regular blender.

Do not be tempted to overly blend. Stop the machine a couple of times to check the consistency. What you’re looking for is a creamy, runny paste with a small amount of broken red beans remaining. This is the optimal texture for me as I enjoy a nice bite of the beans instead of having a completely smooth purée.

That said, please feel free to alter the texture based on your own preferences.

Step 4 (optional): Cook tapioca pearls

Add tapioca pearls and some hot water (same volume of the dried beans) to the blended soup. Cook over very low heat for about 12 minutes until the pearls turn completely transparent.

🛎 Note: Be attentive during this step. Stir the soup from time to time and scrape off anything that sticks to the bottom of the pot. Add more water if necessary as the pearls absorb quite a bit of liquid. Otherwise, you might burn part of the soup as it becomes thicker and thicker.

Step 5: Sweeten

Now you can turn off the heat and stir in dark brown sugar and a pinch of salt. Add it gradually and taste it several times to adjust. My version has a very mild sweetness. Increase the quantity if you like it sweeter.

How to serve

Sweet red bean soup tastes great both warm and at room temperature. I’d have it right after cooking on cold winter days or chill it before eating when the weather is warm.

As the soup cools, its consistency will become thicker. To thin it, simply add a little hot water and mix well.

Make ahead

I always make a big batch of sweet red bean soup and freeze it in portions. Whenever we crave it, I simply defrost the amount I need in the fridge, then reheat it to serve.

Stored in airtight containers, it can be kept in the fridge for up to 4 days or in the freezer for up to 3 months.

Other classic desserts

Looking for more Chinese dessert recipes? Check out these popular ones:

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