Thursday, April 17, 2008

CASE STUDY: Espresso Continued

This is a follow up to my earlier post about bad espresso, this one is about good espresso. While I don't own the world's best espresso machine, it's pretty damned good and produces a good study in how espresso should look as it comes from the machine.

STEP 1: Preparing the cup

Most espresso machines, and I'm not talking about the machines you get at Target, will come with a cup warmer on the top for eliminating the chill of the cups. This is CRITICAL. The hotter you can get the cup, the better. The hotter the cup, the less heat it will immediately sap from the espresso upon pull.

Since the cup warmer on the Capresso Z5 is really bad, I usually use the steam wand to blast raging-hot steam into the cup. I'm using a standard espresso cup with a fun design because this is the cup most people think of when you say espresso. I'll use a clear shot glass later to illustrate the heart and body. Regardless, it will be apparent how the general quality of a shot can be judged even in an opaque cup.

Step 2: Pulling the shot

I'm not actually pulling shot, here, the machine is doing it for me, but you get the picture. Look at the swirling, and the reddish tan color of the espresso as it comes from the machine. It should look like an oil coming from the spout.

Remember, espresso is a colloidal mixture of oils, proteins, sugars, and water. These do not naturally go together, which is why the crema, not so apparent in this photo, will float to the top upon finishing the pull. It's also the reason you need to get this drink to the customer as quickly as possible before separation occurs.

Step 3: Analyzing the shot

Look at that crema! Now that is a good shot. Remember the pathetic, watery crema from shot I showed you, now compare it to this. It's colored perfectly, it forms a dense, oily foam, and completely conceals the goodness below.

No matter the size, you should see this layer form on top. If you're producing a large espresso drink, use two shots. An Americano? Pull the shot directly into the hot water. Even with a lungo, the top should fill with crema. This is the single, most important metric by which to measure a shot of espresso. You can sweat the details of beans, roasts, and grinds, but once all of that is cleared, or you are a barista with no power of those decisions, this is your metier. Crema. Learn it. Know it. Love it.


Temperature is both your friend and your enemy. While it is what allows espresso to exist, the loss of it destroys everything you've worked hard to achieve. As you can see in the photo, the crema completely coats my finger in its oily goodness. This is because of the temperature allowing the oily, sugary, protein-ey mixture to co-exist. In lower temperatures, the various phases of the colloid will separate into various types of disgusting.

As you can see, I pulled the shot and it sat in the cup, the hot cup, for about 90 seconds as I prepared the various photos. A flawless barista will get that espresso to you at 150 degrees, give or take a few. If I gave this to my customer, I was not flawless. Less than two minutes in the cup resulted in a temperature of less than 138-139 degrees. The espresso has already begun its quick, inexorable journey to nastiness and time is against you. Get that espresso served!


I used the opaque cup before to prove a point. I'm now using my chosen method for producing espresso: a clear shot glass.

The clear glass lets you see into the very workings of the espresso shot. Here, you get an even better impression of the oily, viscous nature of espresso and see how truly different it is from drip coffee. At this point, it's a swirly, tan-colored mess of various substances suspended in the hot water. It doesn't look even remotely like coffee because it's so amazingly turbid. If at any point during this early production it doesn't look thick and, well, like this, you're doing something wrong. Maybe your temperature is off, maybe you didn't grind the beans fine enough, maybe your machine sucks and can't produce enough pressure, it doesn't matter. You need to produce better espresso.

Look at that! Look at the dance of colors and textures. It looks more like a freshly draughted Guinness than a coffee. It's at this point that you can see the separation of the heart and body. The heart is the dark, almost black part at the bottom, while the body is the swirling mass of particles that slowly gets consumed by the heart. Think of them as the three, separate phases of the espresso. The crema on top, the mixture of crema and heart in the body, and the body at the bottom. Taking a sip when this swirling is ongoing is one of the best aspects of home-brewed espresso.

In this photo, you can see that the heart has fully consumed the body. Settling is finished and you have only two parts, of which the crema is the only indication of the shot's quality. By this time, the shot should either be in your stomach, on its way there, or in the customer's hands. This settled, side shot also gives you an excellent indication of how thick a well-formed crema should be. In this shot, the crema was over .5cm tall. Anything less and you've got to recalibrate your process. Obviously, the amount of surface area must be considered. A wide-mouth cup would have a thinner layer, and a thinner shot glass could have a bit more.

I hope this has given you an idea of why the shot I got was so bad, and, if you didn't know already, taught you how analyze a shot you may get in a cafe. Making good espresso is at once very simple and very complex. It is something a dedicated coffee connoisseur can do at home, and something you damn well better be a master of before even considering opening a cafe.

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