Homemade Koshian (Smooth Sweet Red Bean Paste)

Method19 steps

1. 1

   Step 1: Wash the 200 g dry adzuki beans in clean water, swilling and draining them two or three times.

   Uses 200 g dry adzuki beans · Clean water for two or three washes

   
2. 2

   Step 2: Transfer the washed beans to a pot and add fresh water to cover them by 1–2 inches. Bring to a boil over medium heat, then boil for 10 minutes.

   First adzuki boil · 10 minUses Washed and drained adzuki beans · Fresh water to cover the beans by 1–2 inches

   
3. 3

   Step 3: Drain the beans from step 2 through a sieve and discard this first cooking water.

   Uses Beans and first cooking water in the pot

   
4. 4

   Step 4: Rinse the pot and return the drained beans from step 3. Add fresh water to cover them by 1–2 inches.

   Uses Beans retained after discarding the first cooking water · Fresh second cooking water, 1–2 inches above the beans

   
5. 5

   Step 5: Bring the beans and fresh water from step 4 to a boil over medium heat. Skim off any foam that forms.

   Uses Adzuki beans and fresh water in the pot

   
6. 6

   Step 6: Reduce the heat slightly and set a drop lid over the beans. Simmer gently for about 40–60 minutes, checking from 40 minutes. Stir occasionally and top up with clean water as needed to keep the beans submerged.

   Check adzuki softness · 40 minUses Skimmed pot of beans and cooking water · Additional clean water as needed to keep the beans submerged

   
7. 7

   Step 7: At the 40-minute checkpoint, take a few larger beans from the pot and cool them under cold water. Press them between thumb and forefinger: they must spread like smooth paste and be soft to the core. If hard or grainy, continue simmering, rechecking every 5–10 minutes until fully soft.

   Recheck beans if still firm · 5 minUses Simmering beans and cooking water · Cold water to cool the sample beans; top-up water if needed

   
8. 8

   Step 8: Once the beans are fully soft, turn off the heat. Set a fine-mesh sieve over a heatproof bowl and pour the pot through it, retaining both the beans in the sieve and the liquid in the bowl.

   Uses Fully soft adzuki beans and cooking liquid

   
9. 9

   Step 9: Crush the cooked beans in the sieve with a pestle, pushing the soft pulp through into the bowl below. Pour over clean water occasionally to loosen the pulp from the skins. Discard the skins that remain in the sieve.

   Uses Cooked beans in the sieve and liquid caught below · Clean water to loosen the bean pulp through the sieve

   
10. 10

    Step 10: Scrape all the bean pulp from the underside of the sieve into the bowl and add fresh water. For an even smoother result, optionally blend this pulp-and-water mixture, then return it to the bowl.

    Uses Bean pulp and liquid retained after discarding the skins · Fresh water for the first settling cycle

    
11. 11

    Step 11: First settling cycle: leave the pulp-and-water bowl from step 10 for 5–10 minutes, checking from 5 minutes, until the paste has settled at the bottom. Carefully pour off the upper water without losing paste, then refill with fresh water.

    First pulp settling · 5 minUses Bean pulp suspended in water · Fresh water after the first decant

    
12. 12

    Step 12: Second settling cycle: leave the refilled bowl from step 11 for another 5–10 minutes, checking from 5 minutes. Once the paste has settled, carefully pour off the upper water and refill with fresh water.

    Second pulp settling · 5 minUses Retained bean pulp and fresh water after the first cycle · Fresh water after the second decant

13. 13

    Step 13: Third and final settling cycle: leave the refilled bowl from step 12 for 5–10 minutes, checking from 5 minutes. Carefully pour off the upper water once the paste has settled, keeping the paste for straining.

    Final pulp settling · 5 minUses Retained bean pulp and fresh water after the second cycle

14. 14

    Step 14: Pour the settled paste and remaining liquid from step 13 into a clean cheesecloth. Squeeze out the water, discard that water and set the crumbly bean paste aside.

    Uses Settled paste retained after the final decant

    
15. 15

    Step 15: Put the 175 g sugar and separate 2–3 tbsp syrup water in a saucepan. Heat over medium-low, stirring continuously until the sugar has dissolved.

    Uses 175 g sugar (I use 60% white sugar, 40% light brown sugar) · 2–3 tbsp water for sugar syrup

    
16. 16

    Step 16: Mix the squeezed bean paste from step 14 into the dissolved sugar syrup from step 15. Stir continuously over the heat until a spatula drawn across the pan leaves a line on its bottom. Stop before the paste becomes too dry; it will firm as it cools.

    Uses Crumbly bean paste after squeezing out the water · Dissolved sugar syrup

    
17. 17

    Step 17: Turn off the heat and mix the ¼ tsp salt into the sweetened bean paste from step 16.

    Uses Thickened sweet bean paste · ¼ tsp salt

    
18. 18

    Step 18: Transfer the koshian from step 17 to a shallow, wide container. Let the initial steam subside, cover with plastic wrap touching the surface and refrigerate promptly. Once chilled, seal with a lid and use within 3 days. Alternatively, divide into convenient portions and freeze for up to 1 month.

    Uses Finished salted koshian bean paste

    
19. 19

    Step 19: The chilled koshian is a prepared filling for a separate Japanese dessert recipe. Keep unused portions refrigerated or frozen as described in step 18; thaw frozen portions in the refrigerator overnight, or thaw in a microwave immediately before use.

    Uses Chilled or frozen prepared koshian batch