Coffee 101 (Part 3)

Coffee 101 (Part 3)


Coffee is a lot like chemistry. Baristas at specialty shops extract flavor using scales, timers and glass beakers and by managing three basic variables: time, turbulence and temperature. For more insight into the beverage’s science, we turned to Rachel Lehman, co-owner of the award-winning CREMA in Nashville, to learn the basics of at-home brewing and the equipment you need to get your own lab started.

Choose Your Method
When asked how many brewing methods there are, Rachel points to a small textbook on a table in the back roasting room at CREMA. (The index listed more than ten – French press, Chemex, Siphon, Eva Solo, auto-drip, etc.) For the clearest flavor – “clarity” in coffee-speak – go with a Chemex. The hourglass-shaped device allows water to seep through ground coffee in a filter (either paper or metal), keeping all of the complex flavors in tact. If you use a French press, the plunging metal filter permits more of the natural oils to remain, giving it a thicker feel.

Temperature And Time
Home-brewing with an auto-drip machine can be a good option as well, Rachel says, but before you buy one make sure it will reach the ideal water temperature for brewing coffee. “The water needs to achieve 205 degrees for proper extraction, but unfortunately, ninety-five percent of home brewers do not get to that point of temperature,” she says. “There are a few brands out there that I trust – like Bonavida – they have a really great brewer that gets to 205.” If you’re using any other brew method, it pays to invest in a combination thermometer/timer. Most of CREMA’s recipes require about 4 minutes of water-to-coffee contact.

Do The Daily Grind
Far from just another gadget, a quality grinder is just as important as your brewer. The goal, Rachel says, is to get the majority of your coffee to the same particle size, because if some particles are too small, they’ll end up over-extracted and bitter, and if some particles are too large, they’ll be under-extracted, leaving your coffee tasting thin. Unlike blade grinders that often produce uneven coffee grounds, CREMA baristas use burr grinders to achieve a more consistent particle size.

Invest In A Scale
Some coffee beans are denser than others, so measuring by the “scoop” is neither precise nor consistent. If using a Chemex or a drip-brewer, CREMA baristas measure 1 gram of coffee grounds for every 16 grams of water. (In other words, a 12-ounce coffee requires 25 grams coffee and 400 grams of water.) “We recommend a scale that has a 0.5g resolution, especially if you want to use it for espresso,” Rachel says. “Plus, when you only weigh out in grams what you’re going to consume – just like a bottle of wine – you will consume all of it, instead of making a whole pot and dumping the rest of it out.”

If you care about coffee enough to spend good money on quality beans, make sure you also invest in good equipment and know how to use it properly. For those in the Nashville area, CREMA will offer classes every Wednesday starting in mid-February, focusing on technique and taste. For more coffee knowledge, read our Part 1 and Part 2 features.

Photo by Takeaway

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