What is good coffee?

Measuring the quality of coffee dates back to the 1950s. At that time, E.E., a professor in the Department of Chemistry at MIT. Lockhart conducted a series of surveys to study American taste preferences. He generally surveyed many coffee drinkers and asked them about their preferences and tastes.

Lockhart published his research with a "coffee brewing control chart", showing what Americans thought was the best coffee in the form of a chart.

Years later, the American Professional Coffee Association (SCAA) confirmed that American tastes had not changed much. For Americans at least, the perfect coffee is coffee with an extraction rate of 18% to 22% and a total solid solubility of 1.15% to 1.35%.

Confused by technical terms? Please don't do this.

The extraction rate refers to the amount of coffee particles extracted from the original dry coffee residue. The total solubility of solids represents the actual percentage of coffee solids in a cup of coffee (commonly known as "brewing strength").

Put this information together and you get the coffee brewing control chart, in which the central area highlights the optimal combination of brewing intensity and extraction rate.

Our purpose of making coffee is to be perfect. Everyone seems to be bragging about their unique and mysterious process of achieving the best extraction rate, but we're here to tell you that it's no big deal.

Instead, the key is based on the golden ratio of one serving of coffee to 17.42 parts of water. This ratio best takes you to the best area, and there is no unit limit, which means it's up to you whether you want to be in grams, ounces, pounds, quartz stones or tonnage units.

Therefore, if you want to make coffee with an extraction rate of 20% and a total solid solubility of 1.28%, you can use 30 grams of dry coffee and 523 grams of water as the base, and then adjust it on this basis.

At the same time, the concepts of extraction rate and total dissolution of solids are often mistakenly confused. It is important to figure out the difference between the two concepts.

Brewing strength refers to the amount of solid coffee dissolved in your coffee. And the extraction rate indicates the amount of extract you get from dry coffee ingredients. The point is, espresso has nothing to do with bitterness, caffeine content or baking curve, only with the ratio of coffee to water in your cup.

The measurement methods of all these values were greatly innovated in 2008. A company called Voice Systems Technologies decided to apply the refractometer principle-- a refractometer is an instrument used to detect light waves refracted by particles-- to a project and developed a coffee concentration analyzer called ExtractMojo.

This instrument can accurately display the total solid solubility of coffee, and then compare it with the "coffee brewing control chart", so that you can prepare better coffee scientifically and with emphasis on taste.

Some purists object to using such a device to measure the quality of a cup of coffee, which reminds us, as retired Marines, of a similar topic, which is the discussion of gun control.

Is there something wrong with the gun itself, or is it the way people use the gun?

Is there something wrong with the concentration analyzer, or is there a problem with the way people use this instrument?

These issues have triggered heated discussions, and the starting point of the discussion is good. But guns and concentration analyzers are tools, and like other tools, they can be used inappropriately.

Let's look at this in terms of the "fortress principle" (castledoctrine): just use a concentration analyzer quietly at home.