Making coffee is like working in a chemistry lab, except you can wear slippers and sweatpants instead of weird, bulky goggles, it smells good, there’s no TA or grueling report and generally it’s OK to taste anything you want. So in a sense making coffee is nothing like working in a chemistry lab, but they share some methodologies.
Most people don’t jump for joy at the words “hypothesis” or “scientific method.” However, recently I realized everyone I know who consistently makes great coffee treats their art with the meticulous scrutiny and creativity of a scientist. They hypothesize, adjust variables, use controls and record their findings.
This week’s Brewponent is about grinding. If you decide to start making adjustments to your brewing habits, keep in mind that whimsical adjustments are only occasionally successful. The level of nerdiness you approach brew adjustment with is up to you. I like to take brief notes because, like most people, my memory for precise and seemingly insignificant details is not great at 7 a.m.
The coarseness of the grind, brew time, amount of beans and temperature all affect the final taste of your coffee. However, adjusting the grind is by far the easiest way to get good results quickly. When adjusting any of these variables, only change one at a time.
Grinding at home makes a difference. The grinders in coffee shops and grocery stores are good quality, but coffee loses its freshness quickly after being ground. In whole bean form, coffee will last for up to a month after roasting, due to the oil coating the bean. After grinding, the protective layer of oil is gone, and coffee will start to lose freshness within the hour.
The first thing to know about grinding is the effect of particle size. Ideally, for most coffees, about 50 to 70 percent of the coffee essence (oils, acids, caffeine, etc.) should leech into the water. If you grind finer, surface area increases and the coffee will leech faster. A coarse grind will leech more slowly. In methods such as cone, drip and espresso, a finer grind also lengthens brew time (like water moves through gravel faster than sand). In these methods, leech rate and brew time compound one another, making the right grind essential.
The other important aspect of grinding is the type of grinder you use. Blade grinders and conical burr grinders are commonly used at home. Blade grinders, the economical option, function by chopping the beans like a blender. Blade grinders give an inconsistent grind, and with fine grinds like espresso you can burn the beans from friction before they even hit water.
Conical burr grinders cost more, but do a much better job. The best way to understand one is to see the internal burrs — essentially they work by crushing the bean. Hand powered burr grinders are also available, which are awesome for camping.
Blade grinders work well for French press and automatic drip. If you use finer grinds, upgrading to a burr grinder will drastically improve your brew. The most frequent frustration with grinders is having them break a month after purchase. When looking for a new grinder, take your time to read reviews online from multiple sources, especially regarding longevity.