Crema isn’t only for aesthetics, it plays a crucial role in the flavor and quality of the espresso. It traps the essential compound that contributes to the flavor and aroma of the espresso. For coffee lovers, achieving the perfect crema in espresso is a rewarding part of the brewing process. Perfect crema is also an indicator that the espresso is extracted perfectly.
However, getting the perfect crema in espresso is based on multiple factors such as grind size, extraction time, taming pressure, and much more. These factors are not independent but are interconnected. Such as if the grind size is fine the tamping pressure should be light. These are small details that make a big difference in the overall quality of the espresso.
How Does Perfect Crema Look Like
Perfect crema should be a rich, golden-brown layer that resides on the top of the espresso. It is evenly distributed on the top without any gaps. It has a smooth, velvety texture without large bubbles.
The thickness of the crema should be 6 to 7 mm in a standard 30 ml shot of espresso and it should contribute to the 1/10th of the overall shot of espresso.
By stirring the espresso, the crema will mix with the liquid, creating a smooth, integrated texture. On tilting the cup the crema will cling to the sides slightly, indicating its thickness and quality.
How To Get Perfect Crema in Espresso
Here is how to get perfect crema in espresso.
Choose Fresh Coffee Beans
Coffee beans are the freshest and best for brewing when they are roasted. Freshly roasted coffee beans make the best crema. They stay fresh for about 2 to 4 weeks. However, as they get old they start losing CO2 which is the most essential component for making crema.
Therefore aim for coffee beans that are 2 to 4 weeks old. This makes sure that the beans have still enough carbon dioxide trapped inside to make the perfect espresso.
Select The Right Blend Of Coffee Beans
The right blend of coffee beans is key to achieving perfect crema. Arabica beans tend to produce lighter crema due to their lower oil and caffeine content whereas robusta beans contain high caffeine and oil content and produce thicker crema.
You should go for a blend of 80% arabica beans and 20% robusta beans. Italian-style espresso blend which is known for producing good crema also uses 10 to 30 percent robusta beans.
Grind Size For Perfect Crema
Finding the sweet spot for your grind size to achieve perfect crema requires experimentation. A general rule is to aim for a fine grind with a particle size of o.3mm with a consistency similar to a fine granulated sugar. After that adjust the grind size according to the result in the cup.
Try a finer grind if the crema is too thin or the espresso is under-extracted. Conversely, if the crema is bitter and the brewing time takes too long, a coarser grind may resolve the issue.
Also, it is better to brew ground coffee beans within 15 to 30 minutes of grinding.
Tamping Pressure
Tamp evenly and apply a tamping pressure of approximately 30 pounds in the portafilter. This pressure is sufficient to compress the coffee grounds evenly without overpacking them. Avoid inconsistent tamp as it can lead to uneven water flow and poor crema.
The Role Of Pressure
The ideal pressure for an espresso extraction is 9 bars of pressure. This pressure ensures the espresso is not under or over-extracted. This pressure is enough for hot water to extract the essential compounds from coffee grounds.
The espresso will become under-extracted if the pressure is low such as 6 bars. The espresso will be sour and with thin or no crema.
Conversely, if the pressure is high such as 12 to 15 bars, the espresso will become over-extracted. At high extraction pressure, the espresso will be bitter with thick and overly bubbly crema.
Water Quality and Temperature
The quality and temperature of the water can have a significant impact on the espresso. For the best result use fresh filter water with balanced mineral content. Avoid using distilled water. Ensure the temperature of the water is 90°C to 96°C or 195°F to 205°F. Avoid using boiling water as it can lead to over-extraction, whereas cool water can cause under-extraction.
Before you start extraction make sure the espresso machine is properly heated and maintains a stable temperature throughout the brewing process.
Extraction Time
The sweet spot for an espresso extraction is 25 to 30 seconds. This time frame is perfect for hot water to extract all the essential compounds from the coffee grounds that contribute to the flavor, aroma, and velvety texture of the espresso.
However, it is important to note that the ideal extraction time is just a guideline. Various factors such as dose size, tamping pressure, extraction pressure, and many more factors affect the extraction time. Adjusting any of these factors may require changing the extraction time to maintain the desired flavor and crema characteristics. You can read our complete blog post on the extraction timing.
How To Fix Crema
Even the best baristas can face issues with the crema. Here are some common issues and their fixing technique.
Thin Crema
In this crema is present but lacks thickness and richness. This can be caused by using stale coffee beans or using overly coarse grinds or insufficient tamping pressure.
To fix thin crema use fresh coffee beans, make the grind finer, and apply even tamping pressure of 30 pounds. Also, ensure that the machine water and temperature pressure are correct.
Pale Crema
Pale crema indicates under-extraction or other issue. It occurs if the grind size is coarse, the water temperature is low, or the extraction time is too short.
Fixing the grid size to fine, maintaining the water temperature between 90°C to 96°C, and extending the extraction time to the range of 25 to 30 seconds can fix the issue of pale crema.
No Crema
In this situation, crema is either too little or maybe absent. This can be caused by using old beans, applying low pressure, and using improper grind size.
To fix this issue make sure to use fresh beans, apply a pressure of 9 bars during extraction, and start by using fine grind with a particle size of 0.3 mm and then adjust it from there.
Also, clean and maintain your espresso machine regularly to prevent build-up and ensure it works properly.
Espresso Machine Maintainance
Over time coffee oils, residues, and other minerals build up in the machine and affect the taste and crema of the espresso. To prevent it from happening regularly clean your espresso machine.
To clean your espresso machine you can run water to the group head to clear any coffee grounds. Also, wipe down the portafilter and basket after each use.
You can also use backflush detergent once a week to clean the internal component. This detergent is specifically designed for espresso machines.
By cleaning it you will not only have a perfect shot of espresso every time but you will also extend the life span of the machine.
Conclusion
Achieving the perfect crema in espresso is an art and you can master this art with precision and practice. These guidelines are interconnected, such as a firmer grind may require a light tamp.
However, achieving perfect crema requires a bit of experimentation. Therefore, don’t be afraid to experiment with different grind sizes and blends or tweaking extraction time and temperature.
