- Type of Coffee Beans
- The Roast
- Freshness of the Beans
- Grind and Tamping
- Water Temperature and Pressure
When we talk about crema, our first thought is espresso. There is an adage: “We first eat with our eyes”. The first thing you see in espresso is the crema. To the eyes, the strong presence of crema in an espresso shot indicates a quality, well-ground coffee, and a skilled barista. We asked Dorian Vincent to answer our questions about crema.
So what is the crema exactly?
Crema is a flavorful, aromatic, reddish-brown froth that rests on top of a shot of espresso. Crema helps give espresso a fuller flavor and longer aftertaste than drip coffee. It is formed during espresso extraction.
During roasting, coffee beans undergo many different chemical reactions. Complex carbohydrates are broken down into smaller molecules, beans begin to brown, and a lot of water vapor and carbon dioxide are created.
When the water from the espresso machine is under pressure, it dissolves the carbon dioxide gas that was created in the coffee beans during roasting. When the brewed liquid gets back to normal atmospheric pressure on its way to the cup, the liquid can no longer hold on to all of the gas so it comes out of solution as innumerable tiny bubbles. These bubbles become trapped in the coffee liquid and appear as a stable foam.
What are the elements influencing the crema?
Type of Beans
- Robusta beans will generate more crema, provide more caffeine, and add bitterness.
- Arabica create less crema, lighter crema than robusta, more sweetness, and have a wider flavor profile.
- Dark roast:(more than 20min roasting) little crema
- Medium roast:(20min roasting) lots of crema
- Light roast:(less than 20min) little crema
Fresh roast vs older beans
- Freshly roasted beans will form more crema on the espresso, as they are still releasing gas.
- Older beans are either oxidized or they no longer contain any carbon dioxide.
Grind and Tamping
- Too fine- poor extraction (water cannot properly penetrate); weak crema results.
- Too coarse- poor extraction (water flows through quickly); no crema is formed.
- Proper grind- the right combination of pressure and penetration creates the optimal extraction of fats and carbon dioxide.
- Proper tamping- pressure equaling 30#/square inch provides the correct density
- Water pressure: 8-9 bars
- Water temperature: Between 195-205ºF.
The three main traits you can observe from your crema are the color, the thickness, and stability.Colors will vary as a result of lighter or darker coffee roasts. Light colored crema indicates under-extraction. The issue could come from grinding, tamping, and brewing and simply means that not enough flavor comes out of the coffee grounds.
Darker colored crema is often a product of over-extraction, when too much fat was extracted from the coffee grounds. It could be an issue of too fine of a grind, too much pressure while tamping, or a shot that was pulled too long. The espresso machine could be overheated.
Freshly roasted coffee beans will generally produce a more pronounced crema. This is because beans that were recently roasted are still giving off some of the oils and gasses that begin to release after the roasting process. The more oils inside the beans, the more crema will be produced during the extraction. The fullness of crema varies depending on how the roasted beans were processed: dry processed is most common and leaves beans with more of their natural oils. These oils result in a better, fuller crema. The ideal crema is not too thick or too thin: most baristas aim to have a crema that takes up about 1/10 of the espresso.
Crema will last for about two minutes before it disappears into the rest of the espresso. A crema that lasts for under a minute may indicate a problem.
Malongo espresso pods contain ground 100% Arabica coffee. All of our pods are medium roast, air cooled and are completely airtight. When you open a pod, it is freshly ground coffee. Our pods are designed to be extracted with 8 Bar of pressure at a temperature between 195-202 degree F. Our proprietary pod espresso machines extract a shot in about 23 seconds. All of our 100% natural espressos have a generous crema, defining the finesse and the freshness of our coffee.
Dorian Vincent is a coffee and beverage expert who sells Malongo Coffee in the US.