Exercise 3 - solution (model answer)

Symptoms: bitter, thin and stale together. They partly conflict (bitter often means over-extracted, thin means weak), so test one cause at a time.

Likely causes and changes, in the order to try:
1. Stale coffee: buy fresher beans and grind just before brewing. Try this first because it is cheap and affects every other symptom.
2. Measuring by scoop: weigh the dose and water (chapter 1 and 6 ratio about 15-18:1) to fix thinness without changing anything else.
3. Grind or contact time: if still bitter, grind coarser or shorten the brew (chapter 5 and 7).

Change one thing per brew so you can tell which change worked.