Understanding Espresso Crema: The Complete Guide to Getting It Right at Home

Crema is the essence of good espresso coffee. I like to think of it as the Holy Grail of espresso coffee — without it, you might as well be drinking drip coffee. Getting a rich, persistent layer of crema takes several things coming together at once, and this post walks through each of them.

Espresso shot with crema floating on top
Stylish Glass Espresso Cup with Stainless Steel Handle

There are several elements to "extracting" espresso coffee and achieving rich, creamy crema.

The Beans

Some beans will never produce crema, even some that are sold as espresso roast. The best espresso roasts use primarily Arabica beans, which originated in Ethiopia but have spread throughout the coffee-growing world. Some Robusta beans are typically included in the blend because of their ability to generate crema. Most people imagine espresso roast beans to be dark, but it all depends on the roast — you can get both light and dark espresso roasts. Beans in a light or mid-roast tend to be dry and shrunken compared to dark roasts, which are plump and oily. If you're buying beans from a good source, they should be able to describe the crema-producing qualities of the beans for you. (My recommendation: Coffee Masters Ethiopian Yirgacheffe)

The Grind

It seems everything has to be just so when making espresso and producing good crema. The next thing is the grind. Basically you're aiming to not let the water pass through too quickly, but also not making the grind so fine that your machine can't force the water through without straining. This is achieved two ways: the fineness of the grind, and the tamping of the coffee in the portafilter. To achieve good crema, for a double shot, extract 2 to 2.5 ounces of coffee into your cup in 20 to 30 seconds from the moment you turn on the pump. You'll see this referred to as "The Golden Rule." (I have a completely different Golden Rule for perfect espresso you should read about.) A single shot should still take 20 to 30 seconds, but now you'll want 1 to 1.5 ounces of coffee in your cup.

The flow of the coffee during extraction should be steady and even, coming from both holes of the portafilter. If your beans are ground too coarsely, the flow will be too fast and no crema will be produced.

On the other hand, if they're ground too finely, the flow will be too slow, or there will be hardly any flow at all, and your pump will be straining. To a certain extent, you can compensate for a too-coarse grind by tamping harder, or for a too-fine grind by tamping more gently. With a bit of trial and error, adjust your grinder setting until you achieve the correct flow and perfect crema production. You'll want a conical burr grinder that grinds beans to an even consistency and offers multiple grind settings. Here's my recommendation for a conical burr grinder (Breville Smart Grinder).

Tamping

Tamping is the process of pressing down on the ground coffee in the portafilter with a tool known as a tamper. The tamper should fit snugly into the filter basket. Tamp with even pressure of about 30 lbs. How do you know what 30 lbs feels like? Get out your kitchen scales, put them on the counter, and practice until you get a feel for how hard you need to press. Tamping aims to achieve an even, consistent flow of water through the coffee. If the coffee is packed unevenly, water will find its way through gaps, flowing too quickly through the loosely packed areas and barely at all through the rest. In fact, if you bang out the coffee puck after extraction, you can sometimes see whole areas that are completely dry. You can't make good crema without tamping your coffee properly before extraction.

Correct Brewing Temperature

The water has to be hot enough to caramelize the sugars in the coffee to produce crema. The optimal range is around 92 to 96 degrees Celsius (198–205 Fahrenheit). The best machines use a metal for the boiler with good heat retention, such as brass. Many machines also offer separate boilers for brewing and steaming, since the water used for steaming needs to be heated to a higher temperature than is ideal for brewing.

Correct Brewing Pressure

Effective brewing requires pressure of at least 130 psi, which some domestic machines simply can't manage. Your machine's pressure rating will be quoted in "bars." Many cheaper domestic machines top out around 8 bars, which is a stretch for producing good crema — look for a machine rated at roughly double that. These are sometimes described as "semi-commercial," but don't be fooled by the label; consider this the minimum standard for a home espresso machine. (My recommendation: Breville BES900XL Dual Boiler Semi Automatic Espresso Machine or the Gaggia Evolution. See my reviews.)

At the beginning, expect a certain amount of trial and error. Practice, practice, and practice some more. Vary everything: the grind, the tamping pressure, and your beans.

With a little practice, provided you're using good fresh beans, you too will be pulling the perfect espresso shot with a rich layer of crema floating on top. Yum!

Related Reading

• The Golden Rule of Espresso Coffee Making
• Discovering the World of Espresso Beans