Grind the Coffee

1. Flip the switch on the coffee grinder and grind a small amount of coffee. Coffee beans shouldn't be ground until you're ready to use the coffee, because air oxidizes the oils encased in the beans, causing them to dry out and become stale, according to the Allman Coffee Co.

2. Prepare the test shot. Release the ground coffee into the portafilter, then tamp it with the equivalent of 60 pounds of pressure. Make sure the surface of the coffee puck is smooth, so that water passes through it evenly and doesn't run down into miniature culverts.

3. Gently brush off the rim of the portafilter to prevent extra coffee from being ground into the espresso machine.

Pull a Test Shot

1. Fit the portafilter snugly into the espresso machine's group head, and then press the button to start the espresso brew.

2. Examine the flow of the espresso. It should fill a 1.5-ounce shot glass in between 23 and 28 seconds, beginning when you push the start button. It should be the color of warm honey, and be the size and shape of a mouse's tail.

3. Remove the portafilter, shake out the used coffee puck, and discard it.

Adjust the Grind

1. Adjust the grinder to a coarser grind if the flow of the espresso is thin. The coffee may have been ground too finely, making the coffee puck more dense and difficult for water to pass through. This extends the brew time by a few seconds, enough to make an espresso shot bitter.

2. Move the grind setting a centimeter or two to the left or right. The lever is frequently located at the base of the hopper used to hold the unground beans. The direction for "fine" or "course" should be marked on the grinder, but can be found easily through trial and error.

3. Adjust the grind setting to "finer" if the espresso comes out in a miniature gush or fills the 1.5-ounce glass in less than 23 seconds. If the coffee is coarse, the hot water won't stick around long enough to brew a strong, flavorful espresso.

4. Empty the compartment that holds the leftover grounds by flicking the release switch if the espresso flowed too quickly or you suspect that the ground coffee was old and had become dried out.

5. Empty the extra grounds, too, if the flow was too slow and you suspect the coffee had been sitting around absorbing the humidity in the air.