Don't we need stomach acid to digest food in the stomach?

Actually, most digestion (breaking food down to its component elements such as sugars, amino acids, and fatty acids) occurs in the small intestine, not the stomach. The stomach churns chewed food much like a cement mixer tosses cement, but the acid plays a minor role in that process. The stomach also serves as a reservoir, releasing food into the small intestine at a rate at which the small bowel can process it. When food exits the stomach and passes into the first part of the small intestine (duodenum), it is sprayed by a series of sodium bicarbonate glands (much like a car going through a carwash) to neutralize the acid and make the semisolid material slightly alkaline (ph = 8, for those who remember high school or college chemistry classes.) That is no accident; our pancreatic enzymes, which actually catalyze the digestion of food in the beginning of the small intestine, actually work their best at ph=8.