Black coffee refers to coffee without any modification. Don't add milk, sugar, syrup and the like. Coffee in Cantonese and black coffee in Shanghai female population are all explained in this way. Perhaps it is because coffee in the old days was difficult to swallow without adding some sugar and milk, so that the definition of single product coffee was extended later. When making it, it is still a cup of black coffee, and guests can add sugar and milk. Flannel filtration is more common in this era. Coffee is just coffee, so it's hard to know where it comes from.

The efficacy of black coffee

Coffee can make the mind clearer, have enough thinking ability, pay attention to concentration and improve work efficiency. Caffeine can release muscle contraction and improve motor function. Caffeine can stimulate gastrointestinal secretion of gastric acid, promote intestinal peristalsis, help digestion and prevent gastroptosis. Caffeine can promote renal function, expel excessive sodium ions from the body, increase urination, and improve abdominal distension and edema.