Coffee Beans
Coffee beans (more accurately seeds, but we’ll stick with the common term) start off green and extremely hard. During the roasting process, they dry out, expand in size, and go through a very complex chemical change. They begin changing colors, first slowly turning yellow, then tan, and quickly followed by various shades of darkening brown, and finally ending at a blackened and very oily mess which is, well, burnt. It is during this final stage of rapidly darkening color that the beans are fully roasted and can be turned into quality coffee or espresso.
The ideal roast for a coffee bean depends primarily on its origin. There are a lot of variables here which I don’t feel qualified to attempt to explain, so we’ll simply summarize it this way: if you’re buying coffee beans to use for making espresso, look for “Vienna”, “Italian”, or “Espresso” roasts. These are the darker end of the spectrum and produce the most recognizable flavors. Using lighter roasts for making espresso will produce more fruity and complex flavors, which are enjoyable to the coffee connoisseur, but may not be desirable for those just getting started.
Grind
Because the coffee is compacted, which we’ll talk about next, and water is forced through under high pressure, how the coffee is ground is extremely important. As an analogy, think about holding a small metal screen on which you place a large handful of sand. When you pour water onto the sand, the water will drain through the sand and out through the screen, but the speed with which it does so is determined by the type of sand you use.
If it’s sand from the Gulf of Mexico beaches, which is very fine, the water will flow through much slower than it would if you used Pacific Ocean sand which is quite coarse in texture. So it is with coffee.
You can actually grind coffee so fine that water cannot pass through the compacted grounds in the espresso brewing process. Obviously, that won’t work. But make the coffee too coarse, and the water flows through so quickly that it doesn’t fully extract the flavors from the coffee grounds. After we discuss the remaining variables, we’ll discuss how to determine if your grind settings are correct based on the look of the espresso being produced.
Tamping Pressure
If you are using a super automatic, the only setting you have control over is likely the grind, as discussed above. However, if you are using any other type of machine which requires you to manually tamp the coffee grounds, this works in conjunction with the grind setting to produce proper espresso.
For instance, your grind setting may be okay but you may be applying too much pressure when tamping the grounds, which could cause a very slow flow of espresso. Conversely, the grind may be fine but if you do not tamp firmly enough, the espresso may appear watery and blonde too quickly, even though the grind is okay. So, how do you know?
The proper amount of pressure to use when tamping is 30 pounds. To practice applying 30 pounds of force, grab your bathroom scale, set it on the counter, place your portafilter on it, grab your tamper and press! Aim for 28-32 pounds each time, repeating several times to get the feel for it.
Instructions
Now, to properly tamp:
- Add a heaping mound of ground espresso to the portafilter.
- With a spoon handle or other flat item, scrape straight across the surface of the filter so the espresso is even, letting the excess fall off the edge.
- Gently tap the portafilter down on a flat surface to make sure grounds are distributed evenly.
- Use your tamper and apply the 30 pounds of force for just a second or two
- Twist the tamper with very light force as you release to “polish” the puck.
- Give the side of the portafilter a gentle tap with the tamper to remove any excess grounds.
- Polish again by gently twisting the tamper over the top of the puck with minimal pressure.
Note: There is a whole art to tamping. For the type of machine I use to make espresso (a super automatic), it’s a moot point because the machine does this for me. But, there are some great demos on YouTube. Simply search on espresso tamping.
Brew Pressure
Espresso requires pressure, measured in atmospheres or “bars,” to force the water through the coffee grounds. Too little pressure and you end up with a quick brewed drip coffee, which is bitter, lacks the crema, and generally lacks the complex flavor profile of espresso. Too much pressure and, well… things break.
Espresso requires 8 to 9 bars of pressure. You may see machines advertised that produce significantly more pressure than this, but that doesn’t inherently make them better machines.
Water
Both water temperature and hardness play a part in how the final product tastes. Water that is too hard, meaning it contains a lot of minerals, will make espresso bitter. And, over time, hard water will require more maintenance for your machine. On the other end of the spectrum, distilled water can make equally poor espresso as it lacks necessary minerals to promote flavor. Generally speaking, tap water or softened water is perfectly fine. But, if your city has particularly hard water and you don’t have a water softener, you could consider using bottled water to get a better quality espresso.
Water Temperature
In addition to water quality, the temperature is also critical. Most machines will maintain the temperature properly for you, but some of the more advanced machines have temperature controls to help you fine tune the product. The range of 195-200 degrees F is the preferred brewing temperature. This temperature is measured at the brew head where the water comes in contact with the coffee grounds, so it may be difficult to measure. In general, a finished product temperature of 160-165 in the cup indicates that water temperature is correct.
If you find, especially over time, that your espresso no longer has a thick layer of crema on top and your grind and tamping is still appropriate, it may be that your machine is not maintaining the proper water temperature. When the temperature falls below the 195 degree level, espresso is under extracted and will taste very different than what you’ll be accustomed to. If that happens, time to have your machine serviced.
Pulling a Shot
Now it’s time to put all the variables together and pull a shot of espresso. “Pull” is a term that harkens back to the original piston operated machines where you would literally pull a lever to brew the espresso. With your portafilter tamped and inserted in the machine, or if using a super automatic machine then by pushing the button, activate the brewing and start a stopwatch.
If the grind, tamping pressure, and water temperature are correct, the extraction process will take about 15 seconds for a single shot, and about 20 seconds for a double shot. A double shot of espresso (14 grams of coffee) produces no more than 2 ounces. A single shot (about 7 grams of coffee) will produce no more than 1 ounce of espresso.
“Blonding” Process
During the brewing process, you will notice the first few drops of espresso will be a very dark brown color. After about 6-7 seconds, you’ll see more of a reddish brown stream. This should continue until about 18-20 seconds when the stream will turn noticeably lighter, which is “blonding”. Blonding indicates over extraction, meaning you’ve reached the end of the good stuff and the best quality liquid has already been extracted. Brewing past the first moment of blonding will result in a bitter cup of espresso. If you see two white drops atop your finished espresso, known as a “snake bite”, this indicates you should have stopped extraction a second or two earlier.
The extraction should be complete leaving you with right at 2 ounces of espresso and a nice thick layer of crema on top. The crema will begin to settle quickly, and after about 30 seconds you should have a shot.
Note: How do you know if the crema is appropriate? Take just a teaspoon of sugar and lightly pour onto the crema. It should support the weight of it for at least 10 seconds before it falls to the bottom of the cup.
Tasting Straight Espresso
To taste straight espresso (careful, it’s very hot!) you should consume it within the first two minutes. Much like wine tasters do, slurping the espresso while allowing your mouth to also pull in a lot of air will cause the crema and a small amount of espresso to spread across your palette where you’ll experience all the subtle characteristics of its taste.
There should be tones of sweetness for properly extracted espresso. If you are confident that your extraction variables discussed here are appropriate, and the shot seemed to progress fine during the extraction, but it tastes very bitter, then it may be that your machine or grinder are not clean. It is absolutely imperative that grinders and brew groups, in particular, be cleaned after each use. Allowing coffee grounds to build up will create a stale and bitter taste in your espresso that can be extremely difficult to get rid of.
Adjusting Grind
As mentioned earlier, the grind is absolutely critical for good espresso. But how do you determine the proper grind? If you’re using a super automatic espresso machine, the manual should recommend a grind setting to start from. If you’re using a separate grinder, it likely will take more practice to dial in the proper setting.
The goal is to find a grind setting fine enough to sufficiently restrict the flow of espresso for 2 to 3 seconds after brewing begins. Once the espresso begins to flow, it should be slow and quite dark for the next few seconds, then gradually turning reddish brown. In the last second or two of extraction, it approaches a light tan, known as “blonding”. Extraction past this blonding point results in very bitter espresso.
Grind is too fine
If your machine does not produce a flow of espresso within 5 seconds, the grind is too fine and is preventing the flow of water through the grounds. In this case, set your grinder one notch in the coarse direction and grind some more beans. Try brewing the espresso with the newly ground beans.
Grind is too coarse
On the opposite extreme, if espresso begins flowing immediately and appears light in color or watery, the grind is too coarse. Water does not remain in contact with the grounds long enough to properly brew the espresso. In this case, set your grinder one notch in the fine direction and grind some more beans. Try brewing the espresso with the newly ground beans.
Be aware, too, that different varieties of coffee and even different roasting levels may require slight adjustments to the grind settings. If you change types of coffee frequently, it could be a frustrating thing to deal with. Note the grinder settings you use for your coffee so it will be easier to dial in once you have it figured out.