My friends Ben, a former Secret Service sharpshooter who can drop a man at 1,000 yards, and Meg (who cannot) make delicious coffee. I slept over at their fabulous Chesapeake Bay home during Thanksgiving weekend and Ben showed me his trick.
(I have a bedroom in their house, it is known as "Pam's room." Meg has a room at my house, known as "Meg's room." We were roommates for 5 years in our 20s... the separation has never quite been complete...)
So the secret, which I tried at my house:
Salt. Just a few grains over the coffee grounds before you brew it.
The science: salt inhibits your tongue's ability to taste bitterness (that's why you should generously salt your roasted Brussels sprouts, broccoli rabe and the like. You taste the vegetable instead of the bitterness. Don't over salt it, use more than you would normally think would work. It really improves the flavor.)
So a few grains of the stuff -- a tiny pinch between your finger and thumb -- takes the edge off your coffee. Don't try this with iodized salt. Use large grained sea salt -- it's mellower and has larger crystals.
I made coffee this way for my boyfriend last weekend without him knowing -- it was like an awesome commercial about decaf coffee from the 70s -- and he loved it. It really was delicious. We had leftover coffee that we reheated in the microwave the next day and it was still awesome -- smooth and nutty. Give it a whirl.