Water temperature is the one thing that can ruin a cup of premium coffee or improve a cup of average coffee.
Most of us, me included, do not want to spend 10 minutes or so brewing one cup of coffee unless it is a special occasion. I have therefore weighed my beans and water to suit my mug and now measure the equivalent using a measuring spoon and measuring cup. This is much faster than weighing, doesn’t clutter up my wife’s kitchen counter, I don’t get in her way when she is trying to make breakfast and, if I am careful with measuring (I am), makes coffee that we both like. Also, every barista, every coffee association and expert recommends using water at a temperature between 195F and 205F (90.5C to 96.1C). Getting the right temperature also take time, but is worth it.
I like two mugs of coffee in the morning and my wife likes one, so making three pour-overs is a bit of a pain. I dug out our drip coffee maker, ground the coffee, put in the right amount of coffee and water and turned on the machine. Six or seven minutes later we both took a sip and grimaced. Bitter! Smoothed it out with milk; now it was drinkable but not a pleasure. I tried two more times. Each time I ground the coffee just before brewing, measured everything carefully and got the same result. Bitter coffee.
By the third time, I was quite sure that my drip coffee maker has no temperature control. It boils the water and then pours it over the grounds. A classic case of over-extraction.
I also made a mug of pour over. Same coffee, same grind, same water, etc. The only difference was that I made sure the water was at 200F when I poured (I prefer a Fahrenheit thermometer for precise measurement).The difference was night and day. The drip was (again) bitter – both in aroma and flavor – and the pour-over was aromatic and smooth. I have tried that twice more with different coffees using bottled water, and the results are always the same. A perfect mug of coffee.
Water temperature is the one thing that can ruin premium coffee or improve average coffee. Buy a brewing thermometer; use it.