Fermented Tofu

Fermented tofu, also known as “Chinese cheese” or “furu/腐乳”  is a popular ingredient in Chinese cuisine. Let’s learn how to make this savory and versatile ingredient at home using traditional Chinese methods.

What Is Fermented Tofu?

Fermented tofu, also known as fermented bean curd, is a traditional Chinese food product made from tofu that has been fermented and flavored with wine, salt, chili peppers and other spices. 

The fermentation process can vary depending on regional preferences and methods, but generally involves allowing the tofu to age in a fermentation jar for several weeks to several months. During this time, beneficial bacteria break down the proteins in the tofu, resulting in a distinct flavor profile.

Fermented tofu typically has a complex flavor profile that is salty, savory and tangy, with a pronounced umami richness.  

It is commonly used as a condiment or seasoning in Chinese cuisine, where it adds depth of flavor to dishes such as stir-fries, soups, and your hotpot dipping sauce. 

For me, fermented tofu plus rice porridge (congee) is my to-go comfort food when I have no appetite. The savory, tangy, and umami notes of fermented tofu perfectly complement the gentle taste of rice porridge.

Making Fermented Tofu At Home

Making fermented tofu in your own kitchen is simpler than anticipated when you have all the necessary ingredients and tools.

Starter Culture

Beyond the tofu itself, a key component is the starter culture powder, specifically tailored for hairy tofu. The mold spores within this starter culture are naturally derived but meticulously selected and tested to ensure they’re safe for fermenting both hairy tofu and regular fermented tofu. When we introduce the hairy tofu starter culture to the tofu cubes, these advantageous molds thrive, outcompeting harmful microbes and fostering a healthy fermentation process.

It is also possible to ferment the tofu by itself without the using of any starter culture. In ancient China, people would simply cover tofu pieces with hay, allowing them to ferment naturally. There are various microorganisms in nature, and utilizing the naturally occurring mold spores can indeed make tofu grow mold. However, at the same time, many microorganisms that are unhealthy or even toxic can also grow on the surface of the tofu, resulting in the growth of black, red, green, or colorfully varied harmful molds.

First Fermentation

Cut your firm tofu into bite size cubes. Dip the tofu cubes in the starter culture water, then place them on a bamboo steamer lined with a a breathable liner, or on a stainless steel steamer. 
Allow the tofu to ferment at room temperature, ideally between 20-30°C, for 3 to 5 days. I simply positioned them on the rack in my oven and positioned a large baking sheet underneath to capture any liquid that may drip down.

After 2-3 days, the tofu should be covered with a layer of furry mold. That means our first stage of fermentation is completed. 

After first fermentation, the hairy tofu is safe to eat raw, yet it possesses a bland taste accompanied by a pungent, nutty aroma. Consequently, we must advance to a second fermentation stage to infuse the tofu with additional flavor.

Second Fermentation

To safeguard the tofu against harmful bacteria growth, we dip each tofu cube with vodka or potent rice wine. 

Next, we coat every tofu cube with a blend of seasonings, comprising salt, sugar, chili flakes, Sichuan pepper powder, and optionally, red yeast rice powder to impart a vibrant red hue.

Lastly, we place the seasoned tofu cubes in a fermentation jar or glass mason jar, allowing them to ferment at room temperature for a least 2 additional weeks to infuse the flavors into the tofu. 

Ingredients

• 32 oz firm tofu (Or extra firm tofu)
• 5 g hairy tofu starter culture (I bought it on eBay.)
• 50 g cold water
• ½ cup vodka
• ¼ cup salt
• ½ cup chili flakes (Authentic fu ru is very spicy. You can reduce the chili flakes to ¼ cup if you want it to be less spicy.)
• 1 tbsp Sichuan pepper powder
• ½ tsp red yeast rice powder (Optional)

Equipment 

• Knife and Cutting board
• Bamboo steamer (Can also use stainless steel steamer)
• Fermentation jar (Can also use a large glass mason jar)

Step By Step Instructions

1. Cut firm tofu into 1x1x1.5 inch blocks.

2. In a small bowl, mix a packet of hairy tofu starter culture with 50g room temperature water, stirring until it completely dissolves.

3. Dip the tofu blocks in the starter culture water, making sure every side is thoroughly coated.

4. Put the tofu blocks in a clean, dry bamboo steamer or stainless steel steamer. If you wish, you can line the steamer with a breathable liner such as a silicone mesh mat, cheesecloth, or cotton yarn cloth. Avoid using parchment or foil paper as they can block the steamer’s holes and prevent air circulation.

5. Cover the bamboo steamer with it’s lid. For a stainless steel steamer, drape a cheesecloth over it loosely to block light while still permitting air circulation. Position a large baking sheet or plate under the steamer to capture any liquid produced by the tofu during fermentation. Move the steamer to a warm (around 20-30°C or 68-86°F) place. Avoid direct sunlight. Ferment for 3 to 5 days.

6. Pour vodka into a small bowl. Once the tofu cubes grow a layer of furry mold, dip each one individually into the vodka, ensuring complete coverage of all surfaces. Transfer the dipped tofu cubes into a large bowl.

7. In another bowl, measure out the salt, chili flakes, Sichuan pepper powder, and red yeast rice powder, and thoroughly mix them together.

8. Pour the seasonings over the tofu cubes. Put on a pair of food handling gloves and gently coat each piece of tofu with the seasoning mixture.

9. Transfer the tofu cubes into a fermentation jar or a large mason jar. Seal the jar with its lid or water seal. Allow the tofu to ferment at room temperature in a location away from direct sunlight for at least 2 weeks before enjoying.

10. Once 2 weeks have passed, transfer the fermented tofu to an airtight container. Because of its high salt content, it can be refrigerated and stored for up to 6 months.

How to Enjoy Fermented Tofu

Homemade fermented tofu can be enjoyed in many different ways:

1. As a Condiment: Crush a block of fermented tofu with a fork into a paste, and add it to stir-fries, soups, noodles, or meat stews to impart a savory, umami-rich flavor. Use it just like how you use Korean soybean paste.
2. In Congee or Rice Porridge: Serve fermented tofu as a side dish when you enjoy warm rice porridge (congee). The tangy and savory flavors of the tofu complement the mildness of the porridge, creating a satisfying dish.
3. In Salad Dressings: Blend fermented tofu with ingredients like vinegar, oil, herbs, and spices to create a creamy and flavorful salad dressing. Drizzle it over salads or use it as a dip for raw vegetables.
4. Marinated or Grilled: Marinate ribs or other cuts of meat in a mixture of fermented tofu, soy sauce, garlic, and ginger, then grill or bake.
5. Hot pot dipping sauce: When visiting an authentic Chinese hot pot restaurant with a self-service condiment bar, you’ll frequently find fermented tofu, or labeled as “fu ru”, among the secret ingredients used to craft our personalized hot pot dipping sauces. By mashing a portion of fu ru and blending it with soy sauce, vinegar, sugar, chili oil, minced garlic, cilantro, and green onion, you can make a dipping sauce that elevates your hot pot enjoyment to new heights.  

Health Facts of Fermented Tofu

Fermented tofu can be a nutritious addition to your diet, offering several health benefits:

1. Protein: Tofu, the main ingredient in fermented tofu, is a good source of plant-based protein.
2. Probiotics: Fermented tofu undergoes a fermentation process that encourages the growth of beneficial bacteria and enzymes. These probiotics can support gut health by promoting a balanced microbiome and aiding digestion.
3. Nutrient Absorption: Fermentation can increase the bioavailability of certain nutrients in tofu, such as iron and calcium, making them easier for the body to absorb.
4. Reduced Antinutrients: Fermentation can also help reduce the levels of antinutrients found in tofu, such as phytic acid, which can interfere with the absorption of minerals like iron and zinc.
5. Calorie Management: Tofu is low in calories and saturated fat, making it a healthy option for those looking to manage their weight.

However, it’s essential to consume fermented tofu in moderation and as part of a balanced diet. Since a great amount of salt is used to marinate the tofu, fermented tofu is high in sodium, so individuals watching their sodium intake should be mindful of their portion sizes.

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