Extracting caffeine from coffee

We will be extracting some caffeine from coffee today! I used regular coffee grounds, but I think the process is actually faster and easier with instant coffee. In theory the yield should have been hovering around 300mg if ALL the caffeine was removed. However, I got around 10% of that (30mg). Apparently 10g makes about a cup of coffee, so a yield of 30mg isn't that horrible. Industrially, the caffeine is made synthetically and not extracted because it isn't really economical. The only time caffeine is ex