Chinese Food

Making tofu at home is a rewarding culinary endeavor that not only allows you to control the ingredients but also offers a fresh, homemade taste that surpasses many store-bought varieties. One of the key components in tofu production is the coagulant, which is essential for transforming soy milk into solid curds. Among the various coagulants used, internal coagulants, such as magnesium chloride or calcium sulfate (gypsum), stand out for their ability to create tofu with a delicate texture and a mild flavor. This guide will walk you through the process of making tofu using an internal coagulant, focusing on calcium sulfate, a traditional and widely-used choice.

Understanding Internal Coagulants

Internal coagulants work by reacting with the proteins in soy milk to form a stable gel network. Calcium sulfate, in particular, is preferred for making firm or medium-firm tofu due to its ability to produce a cohesive curd structure. Unlike external coagulants like vinegar or lemon juice, which are added directly to the soy milk, internal coagulants are often dissolved in water beforehand and gently mixed into the soy milk, ensuring a more uniform coagulation process.

Ingredients and Equipment

Before diving into the recipe, ensure you have the following ingredients and equipment ready:

• Ingredients:

  • 2 cups of dried soybeans
  • 16 cups of water (for soaking and cooking)
  • 1/4 cup of calcium sulfate (food-grade gypsum powder)
  • 1/2 cup of cold water (for dissolving the gypsum)
  • Optional: Salt (a pinch for flavor enhancement)

• Equipment:

  • Large bowl for soaking
  • Blender or food processor
  • Cheesecloth or fine-mesh strainer
  • Large pot
  • Wooden spoon or ladle
  • Tofu mold or a colander lined with cheesecloth
  • Heavy weights (like a pot filled with water) or a tofu press

Step-by-Step Instructions

Soaking the Soybeans

Begin by rinsing the soybeans thoroughly under cold running water to remove any dust or impurities. Place the cleaned soybeans in a large bowl and cover them with at least 6 inches of water. Allow them to soak for 8 to 12 hours, preferably overnight. Soaking helps soften the beans, making it easier to grind them into a smooth soy milk.

Grinding and Cooking the Soy Milk

Once the soybeans have soaked sufficiently, drain and rinse them again. Transfer the soaked beans to a blender or food processor, adding about 4 cups of water per batch (depending on the capacity of your blender). Blend on high speed until you achieve a smooth, creamy consistency, similar to milk. Repeat this process until all the beans have been blended.

Pour the blended soy milk into a large pot, adding the remaining water (about 8 cups in total, depending on how much liquid you have from blending). Heat the mixture over medium heat, stirring occasionally to prevent scorching. Bring it to a gentle simmer, but do not let it boil vigorously as this can cause the soy milk to curdle prematurely. Once it reaches a simmer, cook for about 5 minutes, then remove from heat.

Preparing the Coagulant

While the soy milk is cooking, prepare the calcium sulfate solution. In a small bowl, mix 1/4 cup of calcium sulfate powder with 1/2 cup of cold water. Stir until fully dissolved. It’s crucial to use cold water to prevent the gypsum from precipitating out before it’s added to the hot soy milk.

Coagulating the Soy Milk

Pour the hot soy milk into a clean pot (if you haven’t already) and let it cool slightly to around 170°F (77°C). This temperature is optimal for coagulation. Stir the soy milk gently to ensure it’s uniform in temperature.

Slowly pour the dissolved calcium sulfate solution into the soy milk, stirring gently but continuously in a circular motion with a wooden spoon or ladle. Avoid stirring too vigorously as this can break up the forming curds. Continue stirring for about 2-3 minutes, or until you see small, grainy curds forming throughout the soy milk.

Separating the Curds and Whey

Once the curds have formed, let the mixture sit undisturbed for about 10-15 minutes to allow the curds to firm up further. You’ll notice a clear separation between the solid curds and the liquid whey.

Gently ladle or pour the whey off the top, being careful not to disturb the curds too much. You can use a spoon to press lightly on the curds to help release more whey. Continue this process until most of the whey has been removed, leaving behind a dense mass of curds.

Pressing the Tofu

Transfer the curds to a tofu mold or a colander lined with cheesecloth. Fold the cheesecloth over the curds and press down gently to remove excess moisture. Place a heavy weight (like a pot filled with water) on top of the curds or use a tofu press to apply pressure. Let the tofu press for about 15-30 minutes, depending on how firm you want your tofu to be. The longer you press, the firmer the tofu will be.

Finishing and Storing

Once pressed, carefully remove the tofu from the mold. It’s now ready to be used in various recipes or stored for later use. Wrap the tofu tightly in plastic wrap or store it in an airtight container with a bit of water to keep it moist. Refrigerate for up to a week.

Tips for Success

• Temperature Control: Maintaining the correct temperature during coagulation is crucial. Too hot or too cold can affect the texture of the tofu.
• Gentle Stirring: Stir the soy milk gently during coagulation to avoid breaking up the curds.
• Pressing Time: Adjust the pressing time based on your preference for tofu firmness.

Conclusion

Making tofu from an internal coagulant like calcium sulfate is a fulfilling process that yields a high-quality, customizable product. With this guide, you’ll be able to enjoy fresh, homemade tofu that’s free from additives and preservatives, tailored to your taste and texture preferences. Whether you’re a seasoned tofu maker or a beginner, the satisfaction of crafting your own tofu from scratch is unparalleled. Happy tofu-making!