How to Make Kuromamecha (Black Soybean Tea) from Scratch

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A delicious caffeine-free drink made from roasted soybeans

Soybeans are known as a great source of protein that can be used to make all sorts of dishes.
But did you know that you can also make tea from them?
In this post, we will show you how to make kuromamecha (black soybean tea) from scratch, roasting kuromame beans using 3 different methods.
This tisane is easy to make, tastes good and you can even eat the remaining beans after steeping as a very enjoyable snack.

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What is kuromamecha?

Kuromamecha is the name for black soybean tea in Japanese.

This infusion is the result of steeping roasted black soybeans in water and since there is no real tea on it, it’s caffeine-free.

Kuromame tea has a mild, nutty and earthy taste and a toasty aroma.

You can enjoy it warm or cold and furthermore, you can eat the soaked soybeans after steeping: they are rich in fibers and most importantly, delicious.

Black soybean tea has also gained some attention thanks its dietary benefits: it’s a source of polyphenols, isoflavones and according to a study by the Journal of Medicinal Food, it can help you lose weight.

How to make kuromame tea from soybeans

Kuromamecha is getting popular as a healthy caffeine free tea alternative, so there are brands that sell pre-made black soybean tea bags.
Here are some examples of well-known brands that sell kuromame tea in Japan:

Premade kuromame tea bags

However, as we said before, you can also make this tea from scratch quite easily at home.
You can do it in the oven, on a pan or even in the microwave.
All three methods give good results, whereas I found it slightly better (more evenly roasted) to use the oven and the pan.

Below you can see how to easily roast black soybeans in 3 different ways, so you can choose the most convenient one for you:

No matter which method you use, the only ingredient you’ll need are dry black soybeans (not canned or already cooked ones).
You will also need water to soak them, but nothing else (no oil or whatsoever).

Roasting black soy in the oven

What you’ll need:
  • oven
  • baking tray
  • parchment paper
How many beans to roast:

As many as you can have in your baking tray after reserving enough room to move them.
Consider that the beans will get a little bigger after soaking.
In our case, we roast 200 gr. (1 cup) kuromame in a 45 x 35 cm oven tray.

  1. Soak the kuromame beans in room temperature water for 8 hours or overnight
  2. Discharge the water and rinse the beans
  3. Let the beans dry naturally for around 8 hours.
    You can also make this quicker by gently taking some of the water excess with a kitchen napkin or cloth.
    However, when roasting in an oven, it’s okay if the beans have some moisture on the outside.
  4. Extend the black soybeans on a baking tray covered with parchment paper (no oil needed).
  5. Roast for around 40-50 minutes at 170ºC (340ºF).
  6. There is no need to pre-heat the oven.
  7. Stir occasionally, approximately after 20 minutes for the first time and after that, every 10 minutes.
  8. The beans we’ll be ready when most beans are cracked and their inner side looks light brown.
  9. Let them cool down before you store them.

You can store roasted black soybeans in an airtight container for around two months.
But I personally don’t have experience on storing these roasted beans for so long because we love them so much that we use them up much sooner.

How to roast black soybeans in a pan on the stovetop

You’ll need:
  • a pan or saucepan without teflon (the beans would ruin the nonstick coating)
  • utensil to stir
  • stovetop
  • colander to strain beans after soaking
Soybean quantity:

Toast as many black soybeans as there is room for in your pan without overlapping. Remember though that after soaking, the beans will somewhat expand.
In our case, we roast 100 gr. (1/2 cup dry soybeans) black soybeans for a 21 cm diameter pan (around 8 inches).

  1. Soak the kuromame beans in room temperature water for around 8 hours
  2. Strain
  3. Let the beans dry naturally for half a day or over a night.
    You can help by gently taking some of the water excess with a cloth.
    Make sure the surface of your beans is AS DRY AS POSSIBLE: this will prevent them from burning on the outside, which gives a bitter taste and makes it more laborious to wash the pan afterward.
  4. Roast the beans for around 30 minutes on low-medium heat. Don’t cover the pan.
  5. Stir often.
    Please, be aware that some beans may pop during roasting.
  6. You’ll be done when most beans are cracked and their inner side looks light brown. They will be somehow chewy though: they harden after cooling.

Trick To Wash Your Pan After Roasting The Beans

Sometimes, specially if the surface of your beans wasn’t well dried, your saucepan will look a little burned after roasting.
But don’t worry: you will be able to get the burnt dirt away very easily.

This doesn’t happen when the beans are well dried… But anyway, it’s easy to get it clean again with some lemon, citric acid or vinegar.

Just pour in the still hot saucepan a little amount of:

  • water (the minimum you need to cover the burnt surface)
  • the juice of a lemon or 1 Tbsp. vinegar or 1 tsp. citric acid powder

Wait until the mixture has cooled down (at least half an hour) and then clean the pan: the scorch will come very quickly off, with practically no rubbing!

Can you roast black soybeans in the microwave?

Yes, you can and this is probably the quickest method to roast black soybeans at home.
Just be careful not to overcook them: when roasting kuromame beans in the microwave, you’ll have to check on them often (at the final stages, every 30 seconds or 1 minute).

Equipment to roast kuromame in the microwave:
  • Strainer
  • Microwave-safe container (no lid needed)
  • Microwave
Beans quantity:

Roast as many beans as there is room for in your container without overlapping.

  1. Soak the kuromame beans in room temperature water overnight.
  2. After discarding the water, drain the beans for a couple of hours.
    You can let them in a strainer and take some excess water with a kitchen cloth or kitchen paper.
  3. Add the beans to your container and roast them for around 5 minutes on 600W.
    Feel free to pause and move the grains once.
  4. After these initial 5 minutes, the beans probably won’t be ready. Move the beans and roast them for another 1 minute.
  5. If they’re still not done, move them again roast them for another 30 seconds or 1 minute. You can repeat this a couple of times until you get the desired result.
    A good indication that the beans are ready, is when most of them are cracked and look dried, but when you bite one of them, they are still soft (they harden when they cool).
  6. Once cooled, you can store your roasted kuromame beans in an airtight container.

How to prepare black soybean tea (kuromamecha)

Black soybean tea

Once you have roasted black soybeans, making tea from them is one of the easiest things you can do.

You can cold steep Japanese black bean tea or prepare it with hot water.

There is no need to worry about oversteeping and you don’t even have to remove the beans before drinking, since you can eat the beans after steeping.

You can also re-steep the beans (while I find it difficult to resist eating the beans after the first steep).

How to make hot kuromamecha

  • Use around 10 beans per cup.
  • Pour boiling water and let steep for at least 3 minutes.

You don’t need to remove the kuromame beans if they don’t bother you.
After steeping, the beans may be eaten as a snack or used as topping.

How to cold steep kuromamecha

  • Put around 10 beans in a cup of water.
  • Let steep for at least 2 hours.

You may need slightly less time when using pre made kuromamecha tea bags, since they have crushed beans instead of whole ones (by the way, you can also roughly crush your beans for example in a mortar).

Looking for further caffeine-free teas that are popular in Japan? Learn how to make them at home:

FAQs about home roasted kuromame tea

What’s the best method to roast black soybeans?

I find using roasting in the oven the most convenient way: it takes some time, but you only have to stir a couple of times, so it’s a very hand off way to get a delicious roasting.
Also, it doesn’t need preheating and afterwards your oven will be ready to prepare any other baking goods.
Roasting kuromame in a pan needs someone to be near the stovetop for quite a long time, but the roasting results are as good as when using the oven.
Roasting in the microwave is my least favorite option because it may be tricky to find the exact time you need with your microwave.
Also, the roasting is less even, with more beans remaining hard (not so bad for making tea, but not ideal if you want to eat them).Three methods to roast soybeans

Can I use black beans to make kuromamecha?

Japanese kuromame tea is made of black soybeans (Glycine max merrit), which are a different type of beans than regular black beans, also known as black turtle bean (Phaseolus vulgaris).
While both share a similar color, they have different textures and taste, so I guess roasting black beans wouldn’t give the same results.Difference between black soybeans and black beans

Can I eat the roasted black soybeans before making tea?

You bet it. Roasted kuromame are delicious on their own.
You can also add them to salads or rice bowls for an extra crunch and flavor.
My family love this snack so much, that the black soy nuts disappear very soon.
But always be careful when eating them: some of the beans that are less roasted may be too hard to eat (even more before soaking them to make tea).Roasted black soybeans

Why are my roasted been too hard to eat them?

You may have over roasted them.
But even when they are too hard to bite them, you can make tea with the beans. If they are still too hard after steeping, don’t eat them.

How long is the shelf life of roasted black soybeans?

To maintain their crunchiness, it’s better to use up your beans in a couple of weeks. However, the tea will good even if the roasted beans are up to 6-8 weeks old.
I recommend to store your roasted kuromame beans in an airtight container in the pantry or in the freezer (specially if it’s going to take time until you use them up).Glass jar storing toasted black soybeans

Do you need to soak black soybeans to make tea?

While we recommend soaking your beans for at least 2 hours (preferably around 8-12 hours), the beans can be roasted without being rehydrated before.
However, when you don’t soak them, they sometimes end up a little too hard to eat them as as snack, specially if roasting them in the microwave.
When the beans aren’t soaked, the resulting tea has a dark purple color and a taste that somehow remains me of mushrooms.Kuromamecha made with soybeans without soaking

How do you drink black soybean tea?

Kuromame tea can be enjoyed both hot or cold and it’s normally served plain.
However, I find adding a splash of milk at the end also goes very well. If you want to try making black soybean milk tea, just make your kuromame tea stronger as usual, for example by using slightly less water.

Home roasted black soybeans tea
5 from 2 votes

Black Soybean Tea Recipe

How to make Kuromamecha roasting soybeans at home
Print Recipe
Prep Time:16 hours
Cook Time:50 minutes
Total Time:16 hours 50 minutes



  • 1/2 Cup Black Soybeans (around 100 gr.)
  • 2 Cups Water enough to fully cover the beans
  • 1 Cup water for making tea


  • Soak the black soybeans for at least 2 hours (better if for 8 hours or overnight)
    Soaking black soybeans in water before roasting
  • Drain beans. Air dry them as good as possible – this step is very important when roasting in a pan*, but not so much if roasting in the oven.
    Straining kuromame beans
  • Roast:
    A) In the oven – 50 minutes at 170ºC (340 ºF) , stirring a couple of times, the first after approximately 20 minutes.
    B) In a pan 40 minutes with low heat, stirring occasionally
    C) In the microwave 5 minutes at 600 W. Add 1 minute (for a couple of times) if needed.
    Three methods to roast soybeans
  • The soybeans are ready when most are cracked and the inner side has a light brown color.
    Roasted black soybeans
  • To make tea, use around 10 roasted soybeans per cup. Soak them in hot water for at least 5 minutes or cold brew them for 3 hours.
    Home roasted black soybeans tea
  • You can eat the soaked soybeans.
    Black soybeans after steeping


For more details on how to roast following each method, look at the instructions in the post above.
*If your pan look burned after roasting, try this trick to get it clean easily and without rubbing.


Calories: 6kcal
Course: Drinks, Snack, Tea
Cuisine: Japanese
Keyword: caffeine free, hot drink, Japanese tea
Servings: 10 servings
Calories: 6kcal

If you’re looking for an interesting and tasty tea that happens to be caffeine free, give kuromamecha a try.
If you don’t have pre-made kuromame tea bags, it takes a little bit of time to make, but it’s well worth the effort.
With its mild and nutty flavor, this tea is perfect for enjoying any time of day.
Have you ever tried kuromame tea? What did you think?

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One Comment

  1. 5 stars
    Thank you very much for this incredibly tasty tea.
    I already knew about kuromamecha and its health benefits, but I had never imagined that it’s possible to roast the beans at home.
    What a great discovery!
    Now I love eating these toasted beans.
    I also didn’t know that the beans in the tea bags can be eaten after making tea.
    How pity I was always throwing it away after making tea! Thank you very very much.

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