Coffee Lovers' Filter Tips


March 03, 1996|By ROB KASPER

Since the unexamined life is not worth living, I recently took a long look at the way I make a cup of coffee. I tried to do this with a minimum of pretense and a maximum of common sense. I concentrated on the basics of beans, water and pot.

Late one winter afternoon I found myself in the Coffee Mill, in Baltimore's Hampden neighborhood, sipping black coffee made from three different pots. The idea was to see how the three different types of filters in the pots affected the flavor of the coffee.

Presiding over the proceedings was Tom Thompson, proprietor of the Coffee Mill, and a 20-year veteran of the retail coffee business. The three-pot experiment was part of a demonstration that Thompson gives to teach folks the nunances of coffee-making.

A few days earlier he used the routine during a coffee-tasting held at Sam's Bagels in Roland Park, a shop often filled with students from nearby Loyola College. That tasting session came on the heels of a question-and-answer session at Baltimore Hebrew Congregation. These days, he said, coffee is so popular that everybody is curious about it.

Thompson and I tasted coffee from the three pots. So did some of the folks working in his store and a few customers. The same type of coffee was in each pot, Sumatran beans ground to drip-grind consistency. But the flavor produced by each pot was distinct.

The first pot came from an electric drip machine that used a paper filter. This method, all agreed, produced a nice cup of coffee. "Nice and round," said Thompson, using a taster's term meaning the flavors are balanced.

The second coffeepot, also an electric drip, used a gold-washed metal filter to hold the grounds. This cup had even more flavor. "It is not stronger than the coffee from the paper filter, you just taste more going on," Thompson said.

The third pot was a stylish glass pitcher called a plunger pot. Hot water and grounds swam together for a few minutes, then the plunger, a spring-loaded metal filter, descended through the mixture, pushing the grounds to the bottom of the pot. Coffee made in the plunger pot was smooth, rich and had a surprising succession of distinct flavors. It was the top of the heap.

Reveling in a pleasant caffeine glow, Thompson and I talked about the results. It turned out that the best coffee filter was the one that did the least. The paper filter trapped oils and colloids, the suspended particles of solids in the coffee that are too large to fully dissolve but are small enough to pass through a metal filter.

In most cases, trapping oils and anything called colloids sounds like a good idea. But in making coffee, it is not. Colloids give coffee its texture. Oils carry flavor. So when making coffee, you want a permissive filter, one that lets oils and colloids through. The paper filter, like a strict parent, lets little past it.

The gold filter, a moderate, has openings large enough to let some of the colloids get through. The plunger pot takes the free-spirit approach. It lets grounds and water mingle in unfiltered bliss, producing lots of oils and colloids. Eventually the plunger moves through, separating liquids from the grounds.

Convenience is another big factor in the coffee-making picture. The paper-filter method is the most trouble-free; you just toss the spent grounds and filter in the trash. The metal filter requires washing after each use. And the plunger pot is somewhat difficult to use. You have to heat water in a separate vessel, and after brewing you have to take the plunger apparatus apart and clean it. Also, the coffee stays warm for only about 30-40 minutes.

Coffee purists, I later learned, believe that coffee should be drunk within 40 minutes of brewing. Keeping a pot of coffee sitting on a burner oxidizes its volatile oils and throws the flavors out of balance, I was told.

Instead of sitting on a burner, fresh brewed coffee should be poured into a thermal carafe that has been washed out with hot water. That is what writer Corby Kummer says in "The Joy of Coffee" (Chapters Publishing, 1995).

After reading the book, I was inspired to go into my kitchen and check the size of my coffee scoop. A true coffee scoop, Kummer wrote, should hold 2 tablespoons of coffee. Many scoops on the market are too small, he said. Mine passed muster.

Next, heeding another Kummer admonition, I used a measuring cup, not the markings on my electric coffee maker, to determine how much water to put in my electric drip coffee maker. I put in 32 ounces of water, and 6 scoops of coffee. Using these proportions and a gold metal filter, I made about 4 cups, a total of 24 ounces of coffee.

As soon as the coffee was in the carafe, I turned off the burner. I didn't want to oxidize any volatile oils. I let the coffee cool a bit.

It was very good. It was not as flavorful as the coffee that I had tasted a few days earlier in the plunger pot, but better than any brew I had made before. Let the colloids roll!

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