I test piston coffee makers in a similar way to how I test standard drip coffee makers. coffee machines. I start by hand washing and hand drying each product. Then I grind enough coffee beans to achieve a specific brewing ratio. For a French press, that’s 4 ounces of ground coffee to 32 ounces of water.
We test piston coffee makers the same way we test standard drip coffee makers.
Then I add balmy water (203 degrees F, 95 degrees C) or nearly boiling water, into the brew chamber, stir the grounds, and let sit for 4 minutes. Then I lower the coffee plunger with each press and pour a sample of coffee. I then take a sample of the brewed coffee and measure its percentage of total dissolved solids. I exploit a pocket reflectometer for this test. From this I can calculate the percentage of extraction for each batch of brewed coffee.
In the ideal case, the extraction percentage brewed coffee should be between 19% and 22%. While this number alone doesn’t guarantee a delicious joe, it is a forceful indicator of one. Ultimately, the truth lies in a proper taste test.
Coffee Extraction Percentage
Bodum Chambord French Press 21%Bodum Brazil French Press 19%Mueller French Press 27%Hamilton Beach French Press 23%Coffee Gator Piston Brewer 19%French Press Veken 20%French Press Frieling 19%Kona Press 17%SterlingPro French Press 18%OXO Brew Venture French Press Coffee Maker 21%
