[BOOK] Flavor Profile #6: Furu, White Fermented Tofu

Furu, white fermented tofu 腐乳/白腐乳

Introduction

Fermenting soy bean is a corner stone in Chinese cooking, we have soy sauce, douchi fermented soy beans, minsi fermented bean soy bean paste and alike… and there’s also fermented tofu.

Fermented tofu is known for its strong aroma and umami taste, which (to put it overly simplified) comes from mucor and bacteria digesting protein into amino acid and ester. And here’s a general look into how it’s made.

First, making the tofu. Mostly workshops and factories would start from making tofu, i.e. soaking beans → grind into soy milk → strain → cook the soy milk → add coagulant → press and form → cut into small tofu cubes.

When the tofu cubes are ready, the next would be first fermentation.

Traditionally, people would let the tofu cubes sit in a warm place, usually a dedicated room for a steadier microbe environment, and often cover it with straws to keep it warm.

These picture we took at a market in Yibin, Sichuan shows how it looks like and how they season it and jar it up.

There’re three main categories of furu based on the microbe, mucor, rhizopus, and bacteria.

Mucor is the most common microbe found in furu in China and only thrives at a temperature between 18C-30C. That’s why many places would prefer to make furu in spring and autumn.

As for Rhizopus, it’s another major type of microbe that facilitates the first fermentation and it thrives between 30C-40C.

The temperature difference between mucor and rhizopus caused me quite some confusion before. Some English food blogs I found are saying that furu can only be made in summertime, which contradicts with my usual understanding of “spring and autumn is the best furu making time”.

After learning about the optimal temperature for the two microbes, mystery solved. Because those bloggers are from Taiwan and the furu in Taiwan is usually fermented with rhizopus, which requires a higher temperature than mucor. Thus they call for summertime. Meanwhile in many places in mainland, it is mucor that’s doing the work, which needs a lower temperature ranging from 18C-28C, thus spring and autumn is ideal.

Bacteria fermented furu is a rare product, which it’s only produced in Kedong, Heilongjiang and Wuhan, Hubei. Furu powered by bacteria is full of amino acid and resulting in a deep and rich umami, while the downside is that the cube would break a lot easier without the protection from molds, making it more difficult to ship.

Modern workshops and factories would plant the selected microbe strains directly onto the tofu cubes and let it ferment under a controlled environment, resulting in a uniformly white mold growing as you’d see in pictures and videos of furu making. Meanwhile, when people are making it at home, often you’d see different colored molds because of the more mixed microbe growing on the tofu cubes.

Notice that even factories ferment their tofu in a controlled environment, the tofu would still gain a microbe mix during the process and that mix of microbe is differed regionally.

After the first fermentation, the moldy cubes will start the second stage of fermentation.

Sometimes the tofu cubes would be sun dried for a couple days to form a firmer coating before moving on. Regardless, the cubes would then be mixed with salt solution, or coated/layered with salt, other added ingredients include alcohol, seasoning, and spices.

Also in this stage, red yeast rice is added for the production of red fermented tofu, while chili is sometimes added to white furu to make a spicy version.

The second fermentation can range from 5 days to 60 days. In the later stage of this process, sesame oil or chili oil may be added to some furu to create certain flavors.

After this time, the furu will go through sterilization before hitting the market and the ones we got from supermarkets are no longer active. But in China, sometime you’d be able to get some furu straight from a workshop at a market and you can keep aging it at home.

Furu being a widely used condiment in Chinese cooking, its usage can be limitless. Here we’re giving you two recipes showcasing two major way of using it, one flavoring meat and the other one creating a dipping sauce.

Recipe #1 Steamed pork ribs with rice flour, Guilin style 粉蒸排骨（米散肉）

In addition to rice noodles and gorgeous natural scenery, Guilin, in Guangxi province is also famous for its white furu. With its high quality furu, people use it to flavor the meat in the steamed pork belly with rice flour, a classic you’ll see around central and south China.

Besides the good furu, what makes the Guilin version special is the flour mix, which contains toasted rice, beans (like soy bean or mung beans), and nuts (like peanuts or sesame seeds). People would toast them all and grind it into a coarse powder.

Furthermore, I heard people would wrap the meat in lettuce with fried rice when eating. That’s very intriguing to me as this dish is usually just eaten as it is, however, I never seen it myself.

Ingredients:

• Pork ribs (排骨), 500g
• Optional: Taro (芋头) or other root vegetables, 250g

For the spiced rice powder (70g spiced rice powder / 500g meat):

• Jasmine rice (香米), 30g
• Sticky rice (糯米), 20g
• Soy bean (黄豆), 10g
• Peanut (花生) (or white sesame seeds (白芝麻)), 10g
• Star anise (八角), 1/2 a piece
• Cinnamon stick (桂皮), 1/4 a stick
• Sichuan peppercorn, (花椒), 1/4 tsp
• Bay leave (香叶), 1 small piece
• Salt, 1/4 tsp
• Sugar, 1/4 tsp

For the marinate:

• White fermented tofu, furu, (腐乳), 2 piece plus 1.5 tbsp juice
• Soy sauce, (生抽), 1 tbsp
• Liaojiu, aka, Shaoxing wine (料酒), 1/2 tbsp
• Salt, 1/4 tsp
• Sugar, 1/4 tsp
• Optional: Laozao rice wine (醪糟/酒酿), 1 tbsp

Process:

Mash the furu, then massage and marinate the ribs with the marinate for at least 1 hour or up to 48 hours in the fridge.

Toast the rice, sticky rice, soy bean, and nuts in a dry wok for 10 minutes.
Add in the spices when there’s 5 minutes left in the toasting.

If using peanut, pick out and peel the peanut separately then grind them together at the end. If using sesame seeds, add in the sesame when there’s 5 minutes left in the toasting process.

Add in the salt and sugar, grind everything into a coarse powder using a blender, food processor, or mortar and pestle.

Coat the pork belly with the rice powder. Gradually add in the rice powder with 1/4 cup water during the coating process. Keep mixing till it combines and sticks well, without liquid pooling. And 

Evenly lay it in a shallow bowl or deep plate, gently press it into an even layer (it'd be great if you put a layer of root vegetable underneath the ribs too).
Or into a steamer set-up with lotus leaf, loosely wrap the lotus leaf over it, coverthen the steamer. 

For maximum authentic bonus points, lay a piece of reconstituted lotus leaf or banana leave directly onto a bamboo steamer, lay in an even layer of root vegetables to absorb all that flavor. (I also added some fresh cordyceps militaris since we have some laying around, enoki or shiitake would be great for this dish too.)

Bring a big pot of water (at least 2.5L) to a heavy boil, steam the ribs for 45 minutes on medium heat. Come back at the 20-minute mark, slowly pour in three cups of hot water along the sides of the pot to ensure water is not running out.

Serve directly with the bowl or the bamboo steamer.

Note:

Other popular meat choices for this dish in Guilin include pork belly, pork ribs plus the cartilage part around ribs, goose, and duck.

If you don’t have soy bean on hand, you can mix in the same amount of kinako powder (きなこ) into the spiced rice powder to cheat a bit.

Spice mix for the rice flour can be varied. If you want to create your own mix, fennel seeds, ginger, and sand ginger can be a few good choices to begin with, just remember to use a tiny bit as it may be overpowering.

You can make a bigger batch of the rice flour and store it in an air tight container for up to about 3 months (longer would be ok but it may start to lose fragrance). If making a bigger batch of rice powder and using peanut as the nut, toast and peel the peanut separately first, then combine and grind with the rice together later.

Use about 60g-70g rice powder for every 500g meat with about 1/4 cup of water to help it stick.

You can wrap some meat and fried rice with lettuce and eat it as lettuce wrap.

Recipe #2 Yunnan street food style mixed Deep-fried potato 昆明炸洋芋

Deep fried potato is a popular street food through southwest China, in our Guizhou free-style deep-fried potato we made the one that’s popular on Guiyang streets with a heavier sauce and aromatic components.

In the neighbouring Yunnan province, deep-fried potato can also be found on many streets with its own delicious seasoning. So this recipe is a replication of one of the street food versions on Kunming streets, which has less sauce than the Guizhou one, and used furu white fermented tofu as a major seasoning component.

Ingredients:

• Potato, 1 medium-sized, or about 400g

For the sauce:

• Furu white fermented tofu (腐乳), 1 piece
• Soy sauce (生抽), 1/2 tbsp
• Dark vinegar (陈醋), 1/2 tsp
• Roasted chili flakes (糊辣椒) or non-roasted ones, 1 tsp
• Salt, 1/8 tsp
• Sugar, 1/8 tsp
• MSG, 1/8 tsp

For the aromatics:

• Garlic (蒜头), minced, 1 clove
• Xiaomila (小米辣) or Thai bird’s eye, chopped, 1 to 2
• Scallion (小葱), minced, 1 sprig
• Cilantro (芫荽), roots included if possible, minced, 1 sprig

Optional for extra fragrance:

• Toasted white sesame seeds (熟白芝麻), 1/4 tsp
• Huajiao Sichuan peppercorn powder (花椒粉), 1/8 tsp
• Chinese celery (香芹), leaves only, chopped, a small handful

Process:

Peel and cut the potato into 1 1/2 inch biased wedges.

Soak potato for half an hour and rinse off the surface starch. Strain and pat dry. (For patting it dry, I like to put a piece of paper towel in the strainer with the potato and toss them together, works quite well.)

While potato is soaking, mash the furu white fermented tofu, mix in with the rest of the sauces and stir well.

Heat 2 cups of oil to 175C, put in the potato chunks, fry on medium heat for about 10 minutes or until the surface got nice blister with lightly golden brown edges.

Take out the potato chunks, strain the oil real quick, toss in a mixing bowl, add in the sauce, coat the potato chunks, then add in the aromatics, mix well.

Then serve, preferrably eat with a bamboo skewer for that street food feeling.

Note:

You can use whatever potato type according to your own preference. In Yunnan, both waxy and starchy ones are well beloved. For deep frying, personally I prefer using starchy ones.

Some deep-fried potato shops in Kunming have an array of seasonings and aromatics for you to choose from. The most extravagant one I saw has 26 toppings IIRC. So here are only a couple major players that’re commonly seen in this Yunnan snacks. You can play around, especially adding in some spice powder, some of the ones I love include fennel seeds, star anise, and black cardamom, the Yunnan big three.

Depending on where you are in Yunnan, the herbs would vary. Some other common choices include culantro, fishwort, fennel, and mint.