The reason why Changsha stinky tofu turns black is because there are black soybeans and shiitake mushrooms in the brine. When soaked, the tofu will slowly turn black.

After preparing the tofu, Changsha Stinky Tofu adds these two seasonings: shiitake mushrooms and tempeh.

Everyone knows that shiitake mushrooms are black, and so are tempeh. During the further fermentation process of shiitake mushrooms and tempeh, black juice will flow out from the juice of shiitake mushrooms and tempeh, and then the prepared tofu will be Put it into the juice of shiitake mushrooms and black bean sauce to form our common black Changsha stinky tofu.

Extended information:

Changsha stinky tofu is a traditional specialty food in Changsha, Hunan. The locals in Changsha also call it stinky tofu. Black in color, charred on the outside and tender on the inside, fresh and spicy. Crispy but not mushy, tender but not greasy, the smell is tangy at first, and the aroma is tempting when you smell it carefully.

It uses high-quality soybeans to make tofu, and then soaks the tofu in brine containing winter bamboo shoots, shiitake mushrooms, koji wine, and Liuyang tempeh. White hairs will appear on the surface and the color will turn gray.

When you smell the stench at first, fry it slowly in a pan until the color turns black and the surface swells. Then you can fish it out. The aroma will be tempting. Add garlic juice, chili pepper, and sesame oil, and it's ready. Fragrant and crispy, stinky tofu that's crispy on the outside and tender on the inside.

In addition to black, Changsha stinky tofu also comes in yellow and blue.

Reference material: People's Health Network - Is the flavor very different? What are the characteristics of stinky tofu in various places

Baidu Encyclopedia-Changsha stinky tofu