Chapter 7. How to Use a Screening Tool

The perfect temperature for brewing coffee is between 195 and 200 degrees Fahrenheit. I'm pretty sure of that. I run something of a coffee laboratory out of my kitchen. I use terms like roast curve, dosing, and extraction. I don't yet say cupping instead of drinking, but I'm getting close.

Let's say you're in the market for a new coffee maker and you want one with the right brew temperature. (We'll assume you haven't yet discovered that low-tech brewers like press pots and vacuum pots are better than drip coffee makers, and that pressure brewing with an espresso-style machine is better still.) You go online and start searching through models, all the while looking for the following clue:

Brew temperature in degrees Fahrenheit is between 195 and 200.

The Three Parts of Any Clue

The three main elements to stock screening are all contained in your coffee maker clue. There's the variable (brew temperature in degrees Fahrenheit), the relationship (between), and the value (195 and 200).

The Variable

The variable is the piece of information you're making a demand on. Note that the variable just given contains both the data point you're looking for (brew temperature) and the unit of measurement (degrees Fahrenheit). Screeners sometimes have hundreds of variables to choose from. We'll look at many of them in the next chapter. Since there are so many variables for users to choose from, they're generally divided into categories and subcategories. Often, this ...

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