How to make soy milk from dried soybeans?

Whether in the south or the north, people's diet mainly consists of soy milk for breakfast. Soy milk tastes pretty good. First, you can add sugar, or you can add other grains. The soy milk made will be very rich. However, you should pay attention that dry soybeans need to be soaked when making soy milk, because this will make the ground soy milk more fragrant.

Dried soybean milk

First, while not soaking the beans may sound convenient, it actually takes longer. It only takes one or two minutes to soak the beans the night before, but you can make soy milk quickly after soaking; if you don’t soak the beans, the process after starting the soy milk maker will take a lot longer, and it will take a period of heating to promote the beans to absorb water and soften, which is actually more energy-consuming and time-consuming. Therefore, from the perspective of low-carbon environmental protection, or from the perspective of saving time by drinking soy milk in the morning, it is obviously more beneficial to soak the beans.

Secondly, soaking the beans can increase the yield of pulp. Compared with not soaking, the yield of soy milk can be increased by 10% after soaking the beans for 12 hours, while the yield of dregs decreases. Within 12 hours, the longer the soaking time, the higher the pulp yield. In other words, soaking the beans helps break up the tissues, making the soy milk finer and releasing the nutrients better. In terms of taste, soy milk made from soaked beans naturally tastes better.

Perhaps people wouldn’t mind if there was a little more or a little less soy milk. However, there will be obvious differences in the content of anti-nutritional factors in the soy milk made from soaked beans and unsoaked beans.

For example, compared with soy milk made without soaking beans, the tannin content in soy milk made after soaking beans for 12 hours is only half of the former. Even soaking for 4 hours will greatly reduce the tannin content. This is because the tannins partially dissolve in the water used to soak the beans. Tests have found that the longer the soaking time, the more tannins are dissolved in the soaking water. Similarly, compared with soy milk made without soaking the beans, the phytic acid content in soy milk will be reduced by 47% and the saponin content will be reduced by 29% after the beans are soaked for 12 hours.

Tannins and phytic acid will make people feel astringent, and saponins have a more or less soapy taste, so the taste of the soy milk will be significantly improved if the beans are soaked before making soy milk.

However, people may be more concerned about trypsin inhibitors, which are related to the protein digestion and absorption rate of soy milk. Our tests show that the level of trypsin inhibitors in soy milk from soaked beans is about 11 mg/100 ml, which is comparable to the levels of various commercially available cooked soy milk products; while the content in soy milk without soaking beans is 23 mg/100 ml, which is twice that of commercially available cooked soy milk products. That is to say, if the beans are soaked for 12 hours before pulping, the level of trypsin inhibitors in the soy milk will drop by as much as 54%.

It seems that the Chinese tradition of soaking beans overnight before grinding them into soy milk is quite scientific and helps the body make full use of the nutrients in soy milk. Tannins and phytic acid will reduce the absorption of minerals in soybeans, especially iron and zinc; while tannins, phytic acid, saponins and protease inhibitors will reduce the absorption and utilization rate of protein. Especially for those who have poor digestion and absorption functions, and are prone to indigestion, stomach congestion, bloating, or abdominal distension and diarrhea, drinking soy milk made from soaked beans is more conducive to nutrient absorption.

So, how should the beans be soaked, for how long, and at what temperature? We conducted experiments at different temperatures and times, and found that within 12 hours, the effect became better and better as time went on. Soaking for 12 hours at room temperature of 20-25℃ will allow the soybeans to fully absorb water. Prolonging the soaking time will not produce better results. However, in the summer when the temperature is high, soaking the beans at room temperature for 12 hours may lead to excessive bacterial growth, which will make the flavor of the soy milk worse, so it is recommended to soak the beans in the refrigerator. Soaking beans in a 4℃ refrigerator for 12 hours is roughly equivalent to soaking them at room temperature for 8 hours. If you find 18 hours too troublesome, you can soak the beans in the refrigerator for 24 hours, which can achieve the best effect and is very convenient to operate.

However, everything has its pros and cons. Although making pulp from dry beans is not conducive to the digestion and absorption of nutrients, and the flavor and taste are not ideal, it is actually a good thing for those who have hyperphagia, excessive protein and fat intake, and high blood lipids and blood pressure. Therefore, we should thank the designers of soymilk machines for providing consumers with choices suitable for different groups of people. As for the magic of use, it lies in the hearts of users...