Traditional tofu is made by soaking dried soybeans, grinding them into milk, boiling the milk, curdling it with a mineral coagulant, and pressing the curds into a block. The entire process takes about 24 hours from start to finish, with most of that time spent soaking the beans. The hands-on work is roughly 90 minutes, and the only ingredients you need are dried soybeans, water, and a coagulant like nigari (magnesium chloride) or gypsum (calcium sulfate).
Soaking the Soybeans
Start with about 250 grams (roughly 1.5 cups) of dried soybeans, which will yield one or two blocks of tofu depending on firmness. Place them in a large bowl and cover with at least three times their volume in cool water. The beans will more than double in size as they absorb moisture, so leave plenty of room.
How long you soak depends on temperature. At room temperature (around 20°C or 68°F), soybeans reach full hydration in about 12 hours. In a warm kitchen at 30°C, they only need 9 hours. If you soak them in the fridge at 4°C, plan on a full 24 hours. The beans absorb roughly 130% of their weight in water regardless of temperature; warmer conditions just speed things up. You’ll know they’re ready when a bean splits cleanly in half with no dry, opaque core. If the center still looks chalky, keep soaking.
Use soft or filtered water if your tap water is very hard, since mineral content can affect the texture of your final tofu.
Grinding and Extracting Soy Milk
Drain and rinse the soaked beans. Add them to a blender with fresh water at a ratio of roughly 8 to 10 parts water to 1 part dry beans. For 250 grams of dry soybeans, that means about 2 to 2.5 liters of water. If you prefer richer, denser tofu, use less water. Blend in batches until the mixture is as smooth as possible, at least a full minute per batch.
Now strain the blended mixture through cheesecloth draped over a large pot. Gather the cloth into a bundle and squeeze firmly to extract every bit of liquid. The white liquid is your soy milk. The pulp left behind (called okara) is edible and can be used in other cooking, but it plays no role in tofu making. You want every drop of protein-rich milk in that pot.
Cooking the Soy Milk
Place the pot of raw soy milk over medium-high heat and bring it to a boil, stirring frequently to prevent scorching on the bottom. Raw soy milk contains compounds called trypsin inhibitors that interfere with digestion and give the milk a strong “beany” taste. Boiling at 100°C for at least 10 to 20 minutes significantly reduces these. Even after 20 minutes of full boiling, a small amount of inhibitor activity remains (around 13%), but this level is safe and typical of traditionally made tofu.
Watch the pot carefully. Soy milk foams aggressively and will boil over in seconds if you look away. Reduce the heat as soon as it reaches a rolling boil, then maintain a gentle boil for the full cooking time. Some traditional makers skim the foam off the top, which produces a cleaner-tasting tofu.
Curdling With a Coagulant
This is the step that turns liquid into tofu, and temperature matters enormously. Let the cooked soy milk cool slightly until it’s between 70°C and 85°C (158°F to 185°F). Below 70°C, the curds will be soft and runny, failing to hold together. Above 85°C, the protein seizes up into a hard, uneven texture. Aim for around 80°C if you have a thermometer.
The two most common traditional coagulants are nigari and gypsum. Nigari (magnesium chloride) is the mineral-rich liquid left over from sea salt production. It produces a slightly sweet, tender tofu and works best at around 85°C in concentrations of roughly 1.5 to 2 teaspoons per liter of soy milk. Gypsum (calcium sulfate) produces a smoother, silkier curd and is more forgiving with timing. For your first attempt, gypsum is easier to control.
Dissolve your coagulant in about half a cup of warm water. Pour it into the hot soy milk in two or three additions, stirring gently after each one. After the final addition, stop stirring completely. Cover the pot and let it sit undisturbed for 15 to 20 minutes. When you lift the lid, you should see white curds floating in a yellowish-green liquid (whey). If the whey is still milky white, the milk hasn’t fully curdled. You can try adding a small splash more coagulant and waiting another 10 minutes.
If Your Curds Don’t Form
The most common reason for failed curdling is soy milk that’s too dilute. If you used too much water during grinding, there simply isn’t enough protein in the liquid to form a solid curd. Insufficient cooking can also prevent proper coagulation, since the proteins need to be fully denatured by heat before a coagulant can bind them together. If your curds are tiny and scattered rather than forming large, soft masses, try using less water next time and making sure the milk reaches a full boil before you begin.
Pressing the Curds Into a Block
Line a mold with damp cheesecloth, leaving enough overhang to fold over the top. Traditional molds are small wooden boxes with drainage holes in the bottom and sides, but anything with holes works. A clean strawberry basket, a small colander, or even a rectangular food container with holes punched in it will do. The shape of your mold is the shape of your tofu.
Gently ladle the curds into the lined mold. Let the whey drain for a minute, then fold the cheesecloth over the top. Place a flat object (a small plate, a piece of wood) on top of the cloth and add weight. How much weight and how long you press determines the firmness of your tofu:
- Soft tofu: Light pressure (a small plate with a cup of water on it) for about 15 minutes. The block will be delicate and creamy.
- Medium-firm tofu: Moderate pressure (about 0.5 to 1 kg of weight) for 20 to 30 minutes. Good for stir-fries and soups.
- Firm or extra-firm tofu: Heavier weight (1 to 2 kg, like a couple of cans or a heavy book) for 30 to 45 minutes. This gives you a dense block that holds its shape when sliced and pan-fried.
Once pressed, carefully unwrap the cheesecloth. You should have a smooth, solid block. Transfer it to a container of cold water, which stops the pressing process and helps the tofu firm up further. Store it submerged in water in the fridge, changing the water daily. It keeps well for about five days.
Tips for Better Tofu
The protein concentration of your soy milk is the single biggest factor in tofu quality. Thick, rich soy milk makes tofu with better body and a creamier mouthfeel. If your first batch turns out thin or crumbly, use less water during grinding rather than adding more coagulant.
Unbleached cheesecloth is the traditional straining material and can be washed and reused many times. Fold it into at least two layers for straining the soy milk, since a single layer lets too much okara through. For the pressing step, a single layer is fine since you’re just containing the curds, not filtering liquid.
Freshly made tofu tastes remarkably different from store-bought. It has a subtle sweetness and a clean, almost nutty flavor that disappears within a day or two. Many traditional makers eat the first pieces warm, straight from the mold, with just a drizzle of soy sauce. That first taste is the real reward for doing it by hand.