Next, adjust your coffee dose. If you're using more than 18 grams, cut back. A standard double shot is 14–18 grams. Too much coffee means more surface area for over-extraction. Try 16 grams and see if the bitterness softens.

Also, check your water temperature. If your machine runs hot (over 205°F), the water can scorch the coffee. Let the group head cool slightly before pulling, or use a thermometer to verify.