Red bean paste—often called anko in Japanese or dousha in Chinese—is a sweet, smooth or chunky paste made from azuki beans. It’s an essential filling for many Asian desserts like mochi, dorayaki, taiyaki, and steamed buns.

Below you’ll find a step-by-step guide for making classic Japanese-style red bean paste at home, with options for:

  • Tsubuan (chunky red bean paste)
  • Koshian (smooth red bean paste)
  • Less-sweet versions
  • Chinese-style red bean paste tweaks

What Is Red Bean Paste (Anko)?

Red bean paste is a sweetened bean filling made from azuki beans (sometimes spelled adzuki). It’s widely used in:

  • Japanese wagashi (traditional sweets) like mochi, manju, dorayaki
  • Korean desserts (pat, pat-so)
  • Chinese pastries and buns (moon cakes, red bean buns, tangyuan)

The two most common Japanese types are:

  • Tsubuan (つぶあん) – beans are kept intact or lightly mashed; chunky texture
  • Koshian (こしあん) – beans are fully mashed and strained; ultra-smooth texture

Ingredients for Classic Red Bean Paste

Yield: About 2–3 cups of paste (depending on how much you evaporate)

Core Ingredients

  • 1 cup (about 200 g) dried azuki beans
  • 3/4–1 cup (150–200 g) granulated sugar
    • Start with 3/4 cup; add more to taste
  • 1/4 tsp fine salt (enhances sweetness and flavor)
  • Water – plenty for soaking and boiling

Optional Ingredients & Variations

  • 1–2 Tbsp neutral oil (e.g., canola, grapeseed) – more common in Chinese-style paste for extra richness
  • 1–2 Tbsp honey or brown sugar – for a deeper flavor
  • Small piece of kombu (dried kelp) – Japanese method to enhance umami (optional)
  • Few drops vanilla extract (not traditional, but works well in fusion desserts)

Step 1: Rinse and Soak the Azuki Beans

  1. Rinse the dried azuki beans under cold water until the water runs clear.
  2. Place beans in a bowl, cover with plenty of cold water (at least 3x the bean volume).
  3. Soak 6–8 hours or overnight.
    • Soaking helps reduce cooking time and can make beans easier to digest.
    • If you’re short on time, you can skip soaking, but cooking will take longer.

Step 2: First Boil (Shocking the Beans)

Japanese recipes often use a “boil and discard” method to remove some bitterness and impurities.

  1. Drain soaked beans and place in a pot.
  2. Cover with fresh water by about 2.5–5 cm (1–2 inches).
  3. Bring to a boil over medium-high heat.
  4. Once boiling hard for 2–3 minutes, turn off the heat.
  5. Drain the beans and discard the water.
  6. Quickly rinse the beans under warm water.

This step helps create a cleaner, milder-tasting paste.

Step 3: Simmer the Beans Until Tender

  1. Return beans to the pot and cover with fresh water (again 2.5–5 cm above the beans).
  2. Optional: add a small piece of kombu (do not boil vigorously with kombu; remove before a rolling boil to avoid sliminess).
  3. Bring just to a gentle boil, then immediately lower to a simmer.
  4. Partially cover and cook for 45–90 minutes, depending on soaking and bean age.
  5. Add hot water as needed to keep beans submerged.
  6. Start checking at 45 minutes:
    • Beans are done when you can easily mash one between your fingers or with the back of a spoon.
    • They should be tender but not completely falling apart.

Tip: Avoid vigorous boiling during this stage; it can break beans too quickly and make the paste watery or uneven.

Step 4: Drain and Adjust Moisture

For tsubuan (chunky paste) you want less free liquid before adding sugar.

  1. Once beans are tender, drain, but reserve the cooking liquid.
  2. Return beans to the pot.
  3. Add back a little of the cooking liquid as needed to get a thick but stirrable consistency.
    • For chunky paste, you want it fairly thick; you can always thin slightly later.
    • For smooth paste, you’ll adjust texture after straining.

Step 5A: How to Make Tsubuan (Chunky Red Bean Paste)

  1. With beans back in the pot over low heat, add:
    • 3/4 cup (150 g) sugar
    • 1/4 tsp salt
  2. Stir constantly as sugar dissolves.
  3. Gently mash some of the beans with the back of a spoon or potato masher, leaving some whole for texture.
  4. Continue cooking on low, stirring often, until:
    • The paste is thick, shiny, and holds its shape on a spoon.
    • When you drag a spatula across the bottom of the pot, you see the bottom of the pan for a second or two before paste flows back.
  5. Taste and adjust:
    • Add more sugar if you prefer a sweeter paste.
    • Add a tiny splash of water if it becomes too stiff during cooking.
  6. Remove from heat and let cool. It thickens further as it cools.

This tsubuan style is ideal for:

  • Taiyaki (fish-shaped cakes)
  • Dorayaki (red bean pancakes)
  • Simple anko-on-toast (shokupan with butter and anko)

Step 5B: How to Make Koshian (Smooth Red Bean Paste)

For koshian, you’ll strain the beans to remove skins, then sweeten and cook down.

  1. Once beans are tender (after Step 3), drain but keep the cooking liquid.
  2. Transfer beans to a large bowl or pot.
  3. Add some of the hot cooking liquid to loosen, then blend or mash:
    • Use a hand blender, stand blender, or potato masher to make a smooth slurry.
  4. Strain the slurry:
    • Pour through a fine-mesh sieve or nut milk bag into a separate bowl.
    • Press with a spatula or spoon to push the pulp through and leave skins behind.
    • Discard the skins.

At this point you have a bean purée + water mixture.

  1. Let mixture sit for 10–15 minutes; starch will settle to the bottom.
  2. Carefully pour off excess water from the top, keeping the thicker paste at the bottom.
  3. Transfer the thicker paste to a pot.
  4. Add:
    • 3/4 cup (150 g) sugar
    • 1/4 tsp salt
  5. Cook over low heat, stirring constantly to prevent scorching, until:
    • Paste is thick, glossy, and very smooth
    • It pulls away from sides and bottom as you stir.

Cool completely. Koshian is perfect for delicate wagashi, mochi, and fillings where a very smooth texture is desired.

Step 6: Adjusting Sweetness, Texture, and Flavor

Sweetness

  • Traditional wagashi is often quite sweet because the paste is eaten in small amounts.
  • For everyday use (toast, buns), you may prefer 20–30% less sugar.
  • You can balance sweetness with a tiny bit more salt (but don’t overdo it).

Texture

  • Too thick? Add 1–2 tsp hot water at a time, stirring over low heat.
  • Too thin? Continue cooking on low, stirring until water evaporates.
  • For very smooth koshian, blend again after cooking and cooling.

Flavor Variations

Try adding at the final stage of cooking:

  • Honey or brown sugar for caramel notes
  • A tiny amount of vanilla for fusion desserts
  • A knob of butter for a richer spread (non-traditional but delicious on toast)

Chinese-Style Red Bean Paste (Dousha) Tweaks

Chinese-style sweet bean paste (豆沙, dousha) is similar but often:

  • Sweeter
  • Slightly oily and more luxurious
  • Used in buns, mooncakes, and pastries

To adapt the base recipe:

  1. Use 1–2 Tbsp neutral oil when cooking with sugar in Step 5.
  2. Increase sugar closer to 1–1 1/4 cups (200–250 g) for a richer, dessert-style filling.
  3. Cook until paste is very thick, almost dough-like, for use in baked pastries or steamed buns (so it doesn’t leak).

Using Red Bean Paste

Once you know how to make red bean paste, you can use it in many recipes, including:

  • Mochi and Daifuku – soft rice cakes filled with anko
  • Dorayaki – Japanese pancake sandwiches with anko filling
  • Taiyaki / Imagawayaki – stuffed cakes or waffles
  • Anpan – sweet bread buns filled with red bean paste
  • Zenzai / Oshiruko – sweet red bean soup served with mochi
  • Chinese red bean buns (dou sha bao) and moon cakes

You can find typical uses and related dishes in references like:

Storage, Freezing, and Food Safety

Fridge

  • Cool paste completely.
  • Store in an airtight container in the refrigerator.
  • Keeps for 4–5 days.
  • Use a clean spoon each time to avoid introducing bacteria or mold.

Freezer

  • Portion into smaller containers or freezer bags (about what you’d use in one recipe).
  • Freeze for up to 1–2 months.
  • Thaw in the refrigerator overnight, then stir well before using.

Tip: Flatten paste in a freezer bag so it thaws faster and more evenly.

Troubleshooting: Common Problems

Beans won’t soften

  • Beans may be old; very old beans can take much longer to cook.
  • Hard mineral water can interfere; try filtered or soft water.

Paste tastes grainy (for koshian)

  • Strain again through a finer sieve or cloth.
  • Cook a bit longer with enough moisture, then cool; over-drying too fast can accentuate graininess.

Paste burns on the bottom

  • Use low heat and stir constantly after adding sugar.
  • Use a heavy-bottomed pot if possible.

Too sweet

  • Stir in a bit of unsweetened cooked bean paste if you have extra.
  • Next time, start with less sugar and add gradually near the end.

Quick Summary: How to Make Red Bean Paste

  1. Rinse and soak azuki beans 6–8 hours.
  2. First boil and discard water to remove bitterness.
  3. Simmer gently in fresh water until beans are very tender.
  4. For chunky (tsubuan):
    • Drain, return to pot, add sugar and salt, mash lightly, and cook down.
  5. For smooth (koshian):
    • Purée, strain to remove skins, let starch settle, drain extra water, then cook with sugar and salt until thick.
  6. Adjust sweetness and texture; cool and store.

With these steps, you can create authentic homemade red bean paste customized to your taste and perfect for any Asian dessert.

References

  1. Adzuki bean – Wikipedia
  2. Anko (sweet red bean paste) – Wikipedia
  3. Wagashi – Japanese confectionery – Wikipedia
  4. Japanese cuisine – Sweets and snacks – Wikipedia
  5. Red bean paste – Wikipedia