Making tofu at home from soy milk involves a few key steps: creating soy milk from soybeans, curdling the milk with a coagulant, and pressing the curds into a solid block.
Here's a detailed breakdown:
1. Making Soy Milk
- Soaking the Soybeans: Soak dried soybeans in plenty of water for at least 8 hours, or preferably overnight. They will expand significantly.
- Blending: Drain the soaked soybeans and rinse them well. Blend the soybeans with fresh water. A typical ratio is about 1 cup of dry soybeans to 4-6 cups of water, but adjust to your preference. Blending in batches helps achieve a smoother consistency.
- Cooking: Pour the blended mixture into a large pot and bring it to a boil over medium-high heat. Be careful, as it can foam up and boil over easily. Reduce the heat to a simmer and cook for about 10-15 minutes, stirring frequently to prevent sticking and burning. This step is crucial to eliminate anti-nutrients and improve digestibility.
- Straining: Line a large bowl with cheesecloth or a nut milk bag. Carefully pour the cooked soybean mixture into the lined bowl. Allow it to cool slightly, then gather the edges of the cheesecloth or nut milk bag and squeeze out as much liquid (soy milk) as possible. The remaining solids are called okara.
2. Curdling the Soy Milk
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Simmering the Soy Milk: Pour the strained soy milk back into the pot and simmer gently for an additional 10-15 minutes. This helps improve the flavor and texture of the final tofu.
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Adding the Coagulant: The key to making tofu is curdling the soy milk. Common coagulants include:
- Calcium Sulfate (Gypsum): This produces a softer, smoother tofu. Use about 1-2 teaspoons per quart of soy milk. Dissolve the calcium sulfate in a small amount of hot water before adding it to the soy milk.
- Magnesium Chloride (Nigari): This creates a firmer, more porous tofu. Use about 1-2 tablespoons per quart of soy milk. Dissolve the nigari in a small amount of hot water before adding it to the soy milk.
- Lemon Juice/Vinegar: While possible, these create a less traditional flavor and texture.
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Curdling Process: Turn off the heat. Gently stir the coagulant solution into the hot soy milk. You will start to see the soy milk separate into curds and whey. Let it sit undisturbed for about 10-15 minutes to allow the curds to fully form. Don’t over-stir!
3. Pressing the Tofu
- Preparing the Tofu Mold: Line a tofu mold with cheesecloth. If you don’t have a tofu mold, you can use a colander or a container with holes for drainage.
- Transferring the Curds: Gently scoop the curds into the lined mold, being careful not to break them up too much.
- Pressing: Fold the cheesecloth over the curds. Place a weight on top of the cheesecloth-covered curds to press out excess water. The amount of weight and the pressing time will determine the firmness of your tofu. Start with a light weight (like a can of beans) for about 30 minutes for softer tofu, and increase the weight and time for firmer tofu (up to several hours).
- Refrigerating: Once pressed to your desired firmness, remove the tofu from the mold, wrap it in fresh cheesecloth or paper towels, and refrigerate. Change the wrapping daily to maintain freshness. Homemade tofu is best used within a few days.
In short, making tofu at home involves creating soy milk, curdling it with a coagulant, and pressing the resulting curds to achieve the desired firmness. Experiment with different coagulants and pressing times to find your preferred tofu style.