Saturday, January 03, 2009

The quest for the perfect cup of coffee

I enjoy coffee, and am stuck on the quest for the perfect cup. There are so many variables: the quality and temperature of the water, the origin and processing of the coffee beans, the freshness of the coffee roast, the freshness of the coffee grind, the evenness of the grind, the time the grounds spend in the hot water. And of course, how those variables are combined: in an espresso machine, in a French press, in an automatic drip machine or—in my latest and best experiment—a vacuum pot.

French presses have two main flaws: they make too muddy of a cup, and they are prone to over-extraction (if the coffee and hot water are in contact for too long, the beans are over-extracted and bitter compounds are released—most cheap coffee we drink in America is made from too little coffee brewed for too long, resulting in a weak and bitter cup) as you tend to press the plunger and drink off of the still-extracting, slowly-bittering brew as you go (you can fix that by pouring the pot into a thermos immediately after plunging, but who does that?). That just leaves the muddy cup issue.

Most automatic drip machines (the typical American way of drinking coffee) don't get the water to the proper temperature and/or dump the water unevenly on the grounds and/or let the water and grounds commingle for the wrong amount of time and/or lose some of the flavorful oils to the paper filter. The fact is, once you surrender control of so many variables to an "automatic" process, you also surrender the ultimate quality of the final product.

To fix the drawbacks of the auto-drip process, I have been, for the past year or two, using a manual pour-over process. With a filter cone, a permanent gold filter and a tea kettle, you can make a damn good cup of coffee. But the gold filter does leave a little mud in the very last cup.

And then of course there is espresso—the magnifying-glass-on-your-flaws method of brewing coffee. Using a very fine grind, densely packed, being extracted by hot water forced through it under high pressure, the slightest flaw (such as an uneven tamp of the grounds) can produce a worthless shot of espresso. But with such high demands comes a high reward: a perfect shot of espresso is a dense and intense bit of coffee flavor. Like a beautiful piece of dark chocolate, there is nothing quite like it.

Today I tried out the latest method of making coffee: a manual vacuum pot. (I have since stopped using the automatic vacuum pot as I didn't like surrendering control to the automatic process.) My latest and greatest coffee gadget is a Yama 20oz stove-top coffee siphon. I also picked up a used Cory glass rod filter (search on eBay for it; it's a contraption from 1933 that'll run you $5) so that I would never have to replace the cloth filter that came with the Yama.

Vacuum pots are probably the "coolest" way to brew coffee. As boiling water causes steam pressure to build in the bottom chamber, water is forced up the tube into the top chamber, where it is now slightly below boiling temperature; when removed from heat, the decreasing temperature in the bottom creates a vacuum, pulling the coffee from the top back down and filtering it (search YouTube for an example video). Vacuum pots produce an exceptionally clean cup of coffee—even though it's just the friction of a glass rod resting in a tube holding back the grounds. The pressure from the vacuum actually packs the grounds together and pulls the liquid through it, further filtering out the fine sediment.

All things considered, this new brewer has amazing potential. I need some practice to tweak the variables that I control (size of grind, amount of grind, and extraction time), but the beautifully clean cup of coffee and the simplicity of operation will keep me happy for a least until the next cool gadget comes along!

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