Cooking black beans with sour vinegar has no effect on dyeing hair.

under normal circumstances, acetic acid reacts with black beans to separate black, which will generally dissolve in water, and will not react chemically with hair, nor will it react with hair, so that hair will not be dyed black.

the effect of black beans

eating black beans often will have a good effect on blackening hair. If you eat 2 fried black beans and a spoonful of black sesame seeds every night, it will have the effect of blackening hair. For alopecia, you can take boiled black beans, 5 grams each time, twice a day.

Regular consumption of black beans also has a good preventive and therapeutic effect on kidney deficiency, weakness, lumbago, knee weakness, body and face edema, rheumatism, unfavorable joints, carbuncle, swelling and soreness.