Fermented Black Beans

And how to make Black Bean Sauce at home

If you’ve ever had Beef in Black Bean Sauce, you’ll know how delicious that deep, savoury, slightly salty flavour can be. But have you ever wondered what those black beans actually are?

Well, here’s the secret: they’re not the same as the black beans you find in Mexican or South American cooking. Chinese fermented black beans — also called Douchi — are whole soybeans that have been salted and fermented. They’re funky, rich, and full of umami — basically, the backbone of a lot of classic Cantonese sauces.



You can find them in most Asian supermarkets, usually in small plastic or vacuum-sealed bags. They look like little black raisins and smell… well, powerful! But don’t let that put you off — once cooked, they mellow out into something amazing.

What makes them special

Fermented black beans add a punch of savoury depth to stir-fries, sauces, and marinades. They’re what give Black Bean Beef or Steamed Ribs with Black Bean Sauce that unmistakable flavour you can’t get from anything else.



The trick is to rinse them before using — they’re quite salty — and to chop or mash them with garlic or ginger to release their flavour.

How to Make Homemade Black Bean Sauce

Here’s how I make a simple, restaurant-style black bean sauce you can use for beef, chicken, vegetables, or seafood.

Ingredients

Serves: 2-3

• 2 tbsp fermented black beans (rinsed and lightly mashed)
• 4 cloves garlic (finely chopped)
• 1 tbsp light soy sauce
• 200 ml vegetable stock or plain water
• A good pinch of salt and cracked black pepper
• 1 tsp sugar
• ½ tbsp cornflour (cornstarch) mixed with a little cold water
• 2 tbsp cooking oil (for stir-frying)
  

Method

Step 1: Prepare the black beans

I start by rinsing the fermented black beans under cold water to remove excess salt. Then I lightly mash them with the back of a spoon — not too much, just enough to release the aroma.

Step 2: Stir-fry the aromatics

In a wok, I heat the oil over medium heat. I add the chopped garlic and black beans and fry for about 30 seconds until fragrant. This is where the magic happens — the smell is incredible.

Step 3: Add the liquid and seasonings

I pour in the vegetable stock (or water), then add the soy sauce, sugar, salt, and black pepper. Bring it to a gentle simmer and let it cook for a couple of minutes so all the flavours come together.

Step 4: Thicken the sauce

I stir in the cornflour slurry to thicken it slightly — you want a smooth, glossy texture that coats your ingredients nicely. Taste and adjust seasoning if needed.

Step 5: Use or store

You can use the sauce straight away with beef, chicken, tofu, or vegetables — just pour it over your stir-fried ingredients and toss to coat.



If you’ve made extra, let it cool and store it in the fridge for up to a week. It also freezes well in small portions.

Chef’s Tip

Always rinse fermented black beans before cooking — that’s the difference between rich, balanced flavour and something overpoweringly salty. And if you want an extra kick, add a few slices of fresh chilli when frying the garlic.

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