How to calculate the concentration of soybean milk in northeast tofu

The concentration of soybean milk is: soybean: water = 1: 15 (not thinner than this). After the soybean milk is boiled, let it cool. After lactone is dissolved in a little water, pour in soybean milk and stir well. My ratio is 700ml soybean milk, plus 1 teaspoon lactone. When soybean milk is heated or cooked in water, the temperature of soybean milk reaches about 80℃, and it is kept for 65438 05 minutes, and then solidified.