What causes tofu to become bitter when soaked

The bitterness of tofu foam may be caused by improper production process, poor storage conditions, deterioration of raw materials, water quality problems, or excessive additives. It can be solved by adjusting the production process, improving the storage environment, and replacing fresh raw materials.

1. Improper production process

Tofu foam can cause excessive denaturation of proteins and bitter taste if the temperature of the slurry is too high or the proportion of coagulants is imbalanced during the production process. When ordering tofu with traditional brine, excessive magnesium chloride can easily cause a bitter taste. It is recommended to control the slurry temperature at around 75 degrees Celsius and accurately weigh the coagulant.

2. Poor storage conditions

Tofu soaked in high temperature and high humidity environment for more than 24 hours can easily breed spoilage bacteria and produce bitter substances on the surface. When not refrigerated in summer, microbial metabolites can cause soy products to taste bitter. Tofu should be stored in a sealed environment below 4 degrees Celsius.

3. Raw material deterioration

Using moldy soybeans or aged beans stored for more than a year to make tofu pudding, the aldehydes and ketones produced by the oxidation of their fat will bring a significant bitter taste. Fresh soybeans should be plump without black spots, and the water surface should be free of foam after soaking.

4. Water quality issues

Calcium and magnesium ions in hard water combine with soy protein to form insoluble substances, which affect protein extraction rates and produce a bitter taste. It is recommended to use purified water or softened drinking water for grinding, with the pH of the water controlled between 6.8-7.2.

5. Excessive Additives

Some vendors may add preservatives such as sodium benzoate excessively to extend the shelf life, or use industrial grade coagulants, which may cause bitterness. When making homemade products, food grade gypsum or gluconic acid lactone should be chosen as coagulants.

If tofu is found to be bitter in daily consumption, it should be stopped immediately. Bitter substances may contain harmful ingredients. When making a purchase, pay attention to whether the surface is smooth and sticky, and it is best to smell it with a bean like odor without any sour or rotten taste. Homemade tofu pudding is recommended to be made and eaten immediately, refrigerated for no more than two days, and blanched to remove some odors before consumption again. Individuals with gastrointestinal sensitivity should avoid consuming tofu pudding that appears dark in color or has abnormal elasticity to prevent gastrointestinal discomfort.