This is an old New England favorite. It is usually stirred into cold milk (2 to 3 tablespoons per glass). It can also be used to flavor milkshakes, or used as an ice cream topping.
You need a coffeemaker in which boiling water goes through the ground coffee in a filter and drips into a pot. The ingredient amounts will vary depending on your coffeemaker and how much syrup you want to make.
Place enough coffee and water to make 6 servings. Run the coffee cycle as usual.
When the coffee is finished brewing, discard the used coffee grounds and add to the filter a second quantity of coffee sufficient to make 6 servings. This time, instead of adding fresh water to the coffeemaker, pour the already-brewed coffee into the machine. Run the coffee cycle again. You'll end up with double-strength coffee.
Repeat the process again, using new coffee, but reuse the brewed coffee instead of water. In the end, you'll have triple-strength brewed coffee.
Measure the amount of brewed coffee. Add half as much sugar as there is brewed coffee. For example, if after the three brewing cycles you have 5 cups of brewed coffee, add 2 1/2 cups granulated sugar. Stir briskly until the sugar is dissolved. Make sure you add sugar while the coffee is hot so that the sugar dissolves.
Store the syrup in a tightly covered jar in the refrigerator. It keeps a very long time.