Learn how to make fermented tofu, also called “Chao,” from scratch! This 4-ingredient condiment is cheesy and tangy and can be used to add plenty of flavor to soups, marinades, dipping sauces, and more!
Since discovering fermented tofu, I have been using it a lot. Whether it is in soups, marinades, or as a dipping sauce, it can be used in many dishes to add extra flavor, umami, and some cheesiness.
The thing is, fermented tofu is not that easy to find, and let’s be honest, I wanted to learn how to make my own. Here is a guide on how to make fermented tofu (also called Chao) from scratch!
📘 What is Chao?
Chao (which is its Vietnamese name) is tofu that is fermented for at least 1 month in a brine that consists of water, salt, and usually rice wine. According to some books, the technique of making fermented tofu appeared in 200 BC in China.
It is quite salty, sometimes spicy, and has a very soft texture, almost like a paste that you could compare to blue cheese. When Chao is fermented for a long time, it takes a strong flavor, which reminds me of a strong camembert.
What’s great about chao is that it keeps for months, if not years, in its brine!
🥣 How to Make Fermented Tofu (Chao)?
Making chao is easy but requires some patience!
Before starting: As with most fermented recipes, taking care of hygiene is critical to the success of the fermentation process. So I recommend using gloves while handling the tofu to prevent bad bacteria.
Preparing the tofu
It starts with the tofu that is boiled for a couple of minutes in salted water. This step not only helps kill some bacteria but also helps the tofu drain more water.
Next, you want to place your tofu on several sheets of kitchen paper towel, cover it with more paper towels, and place a weight on it to press it and remove excess water. I usually use a large iron skillet that is quite heavy. Leave your tofu like this for about 1 and a half hours, and change the paper towel as needed if it becomes too wet.
Next, cut your tofu into 1-inch cubes. Place them on a plate lined with a kitchen paper towel, then place another piece of paper towel on top and cover the whole plate with plastic film.
Now you want to let the tofu ferment for about 2 days at 77-86°F (25-30° Celcius). So as you can guess, this recipe works best in the summer, but it can also be done during winter if you have a warm spot in your house.
After 2-3 days, the tofu should be slightly orange and a bit stinky (see photo below). It may have some white mold as well; that’s okay. If you see black or blue mold, just scrape it off. A quick tip: if the tofu is not stinky enough when you put it in the brine, you will end up with a mild chao. If it is already stinky, your chao will be stronger.
The hardest part is now done!
Adding to the Brine
The tofu now contains some natural cultures and molds that will work during the fermentation process.
To prevent the tofu from going bad, we need a brine. It consists of boiled water mixed with salt, sugar, and rice wine (or vodka). Place the tofu cubes in glass jars and cover with the brine.
Optionally, you can dip each tofu cube in chili flakes. It makes the chao more flavorful and gives it an appealing orange color. If you plan on using chao to make cheeses, simply omit the chili.
Once your jars are filled, secure them with a lid and place them in a dark place at around 68°F (20°C) for at least 3 weeks.
The longer you let it age, the stronger and softer it becomes. I found that after 6 weeks, the tofu was already creamy and had a nice cheese flavor.
I would not recommend it. It helps with the preservation of the tofu.
No, you shouldn’t have any black mold. If that is the case, start again and make sure all of your tools and plates are clean. Use very clean hands while handling the tofu, or handle it with clean chopsticks.
You can keep chao in your refrigerator for up to a year. I personally had a jar that I kept for over a year, and the chao was still perfectly good!
🥢 How to Use Chao?
Chao can be used in a handful of ways:
- Dipping sauces: Mash a cube of chao and mix it with some lime juice, sugar, chili, and a little bit of water to dilute. The sauce can then be used as a dipping sauce for steamed veggies.
- Vegan cheeses: Since chao is packed with umami and cheesiness, it’s perfect to add flavor to your vegan cheeses! Add half of a cube to vegan camembert or smoked cheese when blending the cashews for a deeper flavor!
- On top of rice: Add some chao on top of steamed white rice and slightly mash it using chopsticks. Chao will add saltiness and cheesiness!
- Stirred into soups: Perfect to take your soups to the next level, you can use it in place of miso.
- Marinades: Combined with soy sauce, sugar, and sesame oil, this fermented tofu can be used as a base for marinades.
- 1 pound firm tofu cut in half
- 4 cups water
- 1 tbsp salt
- optional: 1/4 cup chili flakes
- 1 and 1/2 cup water
- 3 tbsp salt
- 1 tbsp sugar
- 1/4 cup vodka (or 1/2 cup rice wine)
- Before starting: I recommend using gloves when handling the tofu to prevent bad bacteria and mold from growing.
- Bring 4 cups of water with one tablespoon of salt to a boil in a medium-sized saucepan. Once boiling, add the tofu and boil for 4 minutes.
- Remove the tofu from the water and place it on a few sheets of kitchen paper towel. Top with more kitchen paper towel and place a heavy weight on it to press the tofu and remove excess water. I usually use an iron skillet. Let it drain for about 90 minutes, changing the paper towel as needed if it becomes too wet.
- Line a large plate with two layers of kitchen paper towel or a clean towel. Cut the tofu into 1-inch cubes and place the cubes on the plate, leaving about 1 inch between each cube, so they don't touch each other. Top with another sheet of kitchen paper towel and cover the whole plate with plastic film. The plastic film will prevent bad bacteria from reaching the tofu.
- Place the plate in a dark place at 77-86°F (25-30°C) and let it ferment for 2 to 3 days. The tofu will have taken a light orange color and will have a stinky smell. You may also see some white mold as well; this is okay. If you see blue or dark mold, scrape it off.
- Prepare the brine: combine 1 and 1/2 cups of water with the salt and sugar in a saucepan. Bring to a boil and boil for 1 minute. Once boiling, remove from heat and let it cool completely. Add the vodka and stir to combine.
- Transfer the stinky tofu to clean glass jars. If you want to make it spicy, dip each tofu cube in chili flakes before putting it in the jars. Pour the brine into the jars to cover the tofu. Close the jars with a lid and place them in a cool dark place (around 68°F – 20°C) for at least 3 weeks. The longer you let it ages, the stronger and softer your tofu will be.
- For extra flavor, you can add about 1/2 tsp of sesame oil into each jar after the 3 weeks have passed.
- Use this fermented tofu to make dipping sauces, top rice, add to vegan cheeses, and use in marinades, soups, etc.