Representing Espresso Drinking at Its Finest
What is Crema?
Even if you're new to drinking espresso, chances are good that you've had a chance to experience crema. "Crema" the Italian word for "cream" is simply the fantastic layer of foam that sits on top of the espresso and leaves behind a "crema-mustache" if you manage to drink it just right. But, beyond complementing espresso with its look and bubbly appeal, there's much behind what allows a particular batch of coffee beans to make good crema, as well as a revelation about the depth of knowledge and the skill level of the barista working the espresso machine.
What Causes Crema?
Crema is actually formed as a result of gas in the coffee beans. One of the side affects of the roasting process behind coffee beans is the production of carbon dioxide (CO2). While the majority of the gas evaporates as the beans cools and rest, there is also a portion which remains hidden and lingering with the cells of a coffee bean. When those coffee beans are ground, that CO2 suddenly becomes exposed. Hence the shorter the time span between grinding and brewing, the better. When the hot water comes in contact with the ground coffee, it instantly becomes saturated with CO2. This is what creates the tiny bubbles that appear as soon as the liquid is released from the pressure, and when the liquid finally hits your cup, those bubbles get a chance to spread out. However, bubbles do not equal crema. Think of a bottle of soda when opened. Bubbles, yes, crema, no. This is also where things get a little more complicated. In order for foam to form, you need a chemical to wrap itself around each individual bubble, building it up and making it stronger. In coffee, this coating chemical is something known as melanoidin. Because melanoidin is repelled by water, it seeks out the closest source of air (our little bubbles) and voila, instant foam formed! Melanoidin is also destroyed by oils, thus a batch of beans that's particularly high in oil content can cause your crema to vanish more quickly than normal.
Why Crema Is Important
Crema can tell you a great deal about the quality of coffee you're drinking,
as well as how skilled you or your barista is at pulling espresso shots.
If you take time to watch how the crema settles, you can determine the freshness of your coffee. The fresher the coffee, the more of the shot will appear to be crema during the brewing process. Once the pour is finished, then will you see two separate levels. If you're drinking older, staler coffee, then the crema will pour out as a thin stream separate from the coffee and you'll notice a weak, watery coffee with crema that vanishes almost instantly.
The darker the color of the crema, the higher likelihood your espresso is over-extracted
A thick, even crema represents a good extraction pull
What Color Should Your Crema Be?
A good crema will be a reddish-brown color. The lighter the shade, the higher chance your espresso is suffering from under-extraction. This sort of a fast shot will generally produce weak, watery coffee. Likewise, a super dark color is the result of over extraction and often appears as though it's been slightly burnt. You will certainly notice this in the taste as well.
Drink Up, You've Got 60 Seconds!
Producing good crema starts first of all with good beans and a good espresso machine. After that, it comes down to user trial and error. Talk with your local barista about what methods they've found for pulling good shots that produce consistent, quality crema. Many coffee machines take all the work of out producing crema and do a fantastic job of creating a simulated crema for you. Remember, no matter what, you've usually only got about sixty seconds to enjoy crema in its peak, so serve it quickly and enjoy it yourself!