For two years I thought I just did not like black coffee. Every cup I made at home was bitter and harsh, so I would dump in cream and sugar to mask it. Then I had black coffee at a friend’s house that tasted smooth and almost sweet — nothing like what I made at home.

Same beans. Different technique. The bitterness was not the coffee — it was me.

Your Water Is Too Hot

Coffee should be brewed at 195°F to 205°F. Most drip machines run hotter than that. Boiling water poured directly onto grounds scorches them and extracts bitter compounds.

If you use a French press or pour-over, let the water sit for 30 seconds after boiling before pouring. That brings it down to the right range. If your coffee machine has a hot plate, transfer the coffee to a thermal carafe immediately — the hot plate keeps cooking the coffee and builds bitterness.

The Grind Size Is Probably Wrong

Grind size changes everything. Too fine and you over-extract — the water spends too much time in contact with the grounds and pulls out bitter tannins. That was my problem: I was using a fine espresso grind in a French press, which needs a coarse grind.

General rule: coarse for French press, medium for drip, fine for espresso. If your coffee is bitter, grind coarser. If it is sour or weak, grind finer. Adjust one step at a time.

Clean Your Machine

Old coffee oils go rancid and bitter inside your machine. Run a cycle with equal parts white vinegar and water once a month, then two cycles of plain water to rinse. The difference in taste is immediate.