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caffeinated?Archive for chemex
Rinsing Chemex Filters
Though I’m not a huge fan of the Chemex, I thought this might be worth sharing.
My main problem with the Chemex is that I tend to get a papery taste that cuts the finish short. I do use Chemex’s unbleached filters, which I’ve heard produce this result more frequently than the white “oxygen cleansed” ones.
Jim Karr, Intelligentsia’s head of technical services, however, recently informed me that this may be in large part due to insufficient rinsing. I thought this was interesting, and I’ve heard a number of differing theories recently on the most efficient rinsing techniques, so I set up a blind cupping with Jim, Sarah Kluth, and Geoff Watts in the QC lab.
We prepared three Chemex brews, each with the same coffee (our Eros’ Blend, the current holiday blend which is one of the best blends we’ve carried, I dare say) and each with a different filter preparation. The first was rinsed thoroughly with cold water, the second rinsed with hot filtered water poured over the filter and into the Chemex (the water was dumped out before brewing), and the third with a thoroughly rinsed filter in hot tap water.
We cupped blind (except for me) and there was unanimous agreement that the best brew was with the hot water from the tap. In theory, more solubles are extracted with hot water than with cold, and a thorough, open filter rinse allows all loose paper particles to rinse off than with a folded filter.
Incidentally, we brew about 65 grams, ground coarsely (a la French Press) and produce 32 ounces of coffee. We tested brew temperatures the same day as the filter rinse, and found that 98C was optimal, compared with 96C and 100C (boiling). The boiled water produced a rather bitter and astringent coffee, while the low temp was smooth, but less acidic (citric), sweet, and complex. To prevent over-extraction we pull the filter off before all the water has run through and discard it (which can be a little messy but well worth it in terms of flavor). These are specs Sarah introduced me to. It’s a heavy dose, to be sure, but the coarsely ground coffee reduces the dwell time in the filter and produces a more complex cup. I’ll post again sometime with more theory in this vein.
For more on Chemex brewing techniques, coffeed has a pretty thorough discussion here.
Inverting the French Press
I recently read an interesting discussion on an alternative brewing method using an inverted style French Press.
Normally, I add about 5-6 tablespoons of coarsely ground coffee to the press, bring my water to just under boiling (96-98C) and pour, stir, and press down the plunger after 4 minutes. This produces a heavy-bodied cup of coffee, usually a little on the silty side (despite the mesh filter). The benefits of the FP are numerous, among them the ability to completely control all aspects of brewing (temperature, dose, extraction time) as well as a cup that is unadulterated by a paper filter. A lot of people swear by drip coffee or Chemex, 
both of which use a paper filter (unless you’ve got a gold-cone filter on your drip machine–but most of those don’t reach a high enough temperature). I have brewed a number of coffees on the Chemex, including Hacienda La Esmeralda auction lot 2007, and each of them had a papery flavor I found unpleasant and a finish that was less sweet than I would like, both of which I attribute to the filter.
Personally, I enjoy the sediment in the French Press, though I know a number of people that don’t enjoy it. So when I read about a a brewing method in which one inverts the normal proceedure, I was curious to see how efficiently and cleanly it brewed. 
So I set up my press, and ground my coffee, placing it on top of the metal filter. 
I used a Nicaragua that I roasted a little on the light side, just past first crack, and ground immediately before brewing. 
You can see the coffee rests on top of the metal filter. 
I brought the water up to temperature, and poured. 
Afterwards, I let the coffee steep for about 4 minutes.
The idea is to emulate a cupping setup, where the coffee extracts openly in the hot water. In the process of cupping, after the coffee has extracted, the surface tension is broken and then scooped off. In my experiment, I simply pulled up on the plunger.
The inversion is not unlike that of a vacuum pot or even the Clover, in that the extracted coffee is sucked through the grounds in a very efficient way, leaving little residual sediment. 
I found the cup incredibly flavorful, a bit lighter in body than a typical French Press (partly, of course, due to the light roast — though I have pressed the exact same coffee at a similar roast level in the past resulting in a very bright but surprisingly full cup), and the smallest amount of sediment at the bottom, all fines from a less than perfect grinder.
Try this at home, especially if you like the flavor of a French Press, but find the body a little heavy and/or dislike the sediment at the bottom. You’ll be pleasantly surprised.
