Acidity: Are there tannins in coffee?

The other day, someone asked me if there were tannins in coffee. The short answer is, yes, if we define tannins broadly enough, as gallic acid derivatives. But, the truth is a bit, though not much, more complicated. Some confusion arises from the fact that there are different types of tannins. For example, there are hydrolyzable tannins (water soluble) and condensed tannins (non hydrolyzable) and phlorotannins (found in brown algae). More confusion arises from the fact that there are also different types of acids... To keep it simple yet still meaningful, remember that the term "tannin" originates from the tradition...