Vintage RePost: Low Cost Home Coffee Makers
Some people play video games in their spare time, I, on the other hand, like to dissect $8 coffee makers.
It occurred to me the other day, upon spotting a brewer on sale at the grocery store for $7.95, that in all my time in the industry, I’ve merely repeated blindly the theory that cheap coffee makers “don’t get hot enough”, without any due diligence on my end.
What kind of coffee geek would I be if I let this golden opportunity to explore firsthand go to waste? A poor excuse for one, that’s fact.
So, about an hour after this realization, I had my new Proctor Silex on the table. However, before I go into my findings, let me give a quick overview on how drip coffee makers such as this work (for a quicker overview, click on Fig. A below).
From the reservoir, the cool water travels downward through tubing into the heating element. This is usually comprised of two fused aluminum pipes: one filled with a stressed filament surrounded in plaster to act as the heat source, and the other is where water comes to a quick boil.
Fig.A
From here, the water passes through a one-way valve, blocking its pathway back into the reservoir. As it continues to a boil, pressure builds, and the water is forced upwards towards the only available exit left, the brew head. The water is then dispensed over the grounds and down through into the pot.
There is deviance from brewer to brewer, but this is the essential process: reservoir, heating element, brew head, pot.
One of the largest differences you will find in dissecting increasingly expensive brewers is the quality of the components; rubber tubing is replaced by higher and higher quality metals, aluminum heating elements doing the same. Herein lies the difference.
Back to the operating table:
First I drilled symmetrical holes on either side of the brewer, through one I fed a digital probe thermometer an inch into the brewhead. Through the other, I fed a k-type thermocouple down into the ground coffee. I also drilled a hole and inserted another probe into the reservoir to get base readings and to see how warmed the waiting water got due to the poor insulation around the heat sources.
I then made similar accommodations on a commercial Fetco cbs-2031e to act as a control.
There are a lot of words written here to say simply that I was right in my blind trust, but the numbers really don’t lie.
The Fetco’s results were surprisingly accurate, even by commercial grade standards. The slurry remaining almost constant at 199 degrees and the brewhead at 203. Incredibly impressive. The Silex, however, was pretty damned awful. The brew head during the 6 and a half minute cycle varied by as much as 35 degrees, starting at 155 and ending at 190 (this actually is a very kind assessment, seeing as though it didn’t reach 123 degrees until :20 seconds into the cycle; 155 @ :30 and staggeringly only reached its 190 plateau @ 4:00).
My conclusion in all of this is simple; coffee requires hot water to extract flavor oils. The wide sweet-spot of this reaction is between 195-205 degrees and the sweet-er spot is 199-204 degrees. Also, consistency in this temperature is nearly as important as consistency in grind. Fluctuations in temperature during brewing will result in different levels of extraction throughout the cycle and result, on a base level, in a flat, flavorless cup; the coffees full potential still locked in the brew basket.
I know that this blog will not convert people into buying hundred dollar machines when brewers like the Silex will “get the job done” for a fraction of the cost.
I do hope, however, that this will open your eyes to the fact that your cup can get so very much better.
