Learn how to make anko (Japanese sweet red bean paste) from scratch using a pressure cooker or stovetop. Made with just 4 ingredients: adzuki beans, sugar, water, and salt!
Optional Overnight Soak: To speed up the cook time, you can soak the beans overnight. First rinse beans a few times, drain, and place in a large bowl. Add enough water to cover the beans by at least 2 inches. Let the beans soak overnight (at least 8 hours). You can do this at room temperature, unless you live in a very hot/humid environment, in which case I recommend putting the beans in the fridge.
Pressure Cooker
Drain and rinse beans then place in pressure cooker. Add enough water to cover the beans by 2 inches. Cook at high pressure for 10 minutes for soaked beans, 25 minutes for unsoaked beans. Let the pressure naturally release for 20 minutes, then release steam valve and remove the cover once all the pressure has been released.
Stovetop
Drain and rinse beans and place in a large pot. Add enough water to cover the beans by 2 inches. Bring to a boil over medium high heat.
Boil for 2-3 minutes, then turn off heat and drain beans over a strainer. Add beans back to pot, cover with another 2 inches of water, and bring to a boil. Reduce heat to medium low to maintain a gentle simmer.
If you have one, place an otoshibuta (drop lid) over the beans. This will help them to cook more evenly.
Simmer for 1-1½ hours, adding more water as needed to keep the beans covered. The beans are cooked when you can easily smash one between your fingers.
Tsubuan (Chunky Red Bean Paste)
Reserve 1 cup of the cooking liquid. Drain the cooked beans over a strainer, then return the beans to the pot along with ¼ cup of cooking liquid. Heat over medium low.
Add half the sugar to the beans and stir well until dissolved. Then add the remaining sugar and stir well to dissolve. Taste the beans and add more sugar if desired.Tip: If it turns out your beans are still too firm, add more cooking liquid (or extra water) and simmer until the beans are soft to your liking.
Keep cooking and stirring the beans until the mixture has thickened (should take 5-10 minutes). You can add more cooking liquid/water if your beans are too dry. Keep in mind the anko will thicken more as it cools.
Tsubushian: If you want a smoother but still chunky texture, you can make tsubushian by mashing some of the beans.
Turn off heat and stir in salt. Spread out anko in a large heat-safe container (like a baking tray) and let cool completely.
Koshian (Smooth Red Bean Paste)
Reserve 1 cup of the cooking liquid. Drain beans and add to a food processor. Blend into a smooth paste, adding some of the cooking liquid as needed to help blend.
Optional for a smoother paste: Set a strainer over a large bowl. Add blended beans to strainer and use a rubber spatula to press the mixture through the strainer. You should be left with the bean skins in the strainer and the smooth paste in the bowl.
Rinse out your pot then add sugar and 4 tbsp of water. Heat over medium, stirring to dissolve the sugar. Once dissolved, add the bean mixture and mix well.
Taste beans for sweetness. If they aren't sweet enough for you, add more sugar and stir well until dissolved.
Keep cooking and stirring the beans until the mixture has thickened (should take 5-10 minutes). Keep in mind the anko will thicken more as it cools.
Turn off heat and stir in salt. Spread out anko in a large heat-safe container (like a baking tray) and let cool completely.
Storage
Once anko is completely cooled, transfer to an airtight container. Cover and store in the fridge for up to 3 days, or in the freezer for up to 2 months. I like to freeze the anko in ½ cup portions to use for baking.
Notes
Sugar: Typically, anko is made with a 1:1 or even 1:2 ratio (by weight) of beans to sugar. However, I find this way too sweet for my tastes, so I usually do about 1:0.6 or 1:0.75 beans to sugar, depending on how I'm using the anko. But if you are someone who likes the sweetness of store-bought anko, you will want to go for a 1:1 ratio.