Optimal Pressure for Espresso: How Many Bars Are The Best ?

Vietnamese Coffee Exporter
Optimal Pressure for Espresso

Optimal Pressure for Espresso: Pressure is the key factor that distinguishes espresso from other coffee types. Although various coffee makers can produce a short, concentrated brew, it is the high pressure that delivers the distinctive richness and crema we adore.

When considering the amount of pressure required, several figures may be suggested. So, what is the optimal number of bars for a perfect espresso?

Understanding Bars Of Pressure: What Do They Mean?

Let’s start by clarifying the concept at hand. If you’ve ever inflated your tires, you are likely familiar with measuring pressure in PSI. A bar is another unit of measurement, similar to how kilograms and pounds measure mass. Though the bar is not an official unit in the International System of Units, it is frequently used in contexts such as scuba tanks and espresso machines.

Bars are metric units, where 1 bar is roughly equivalent to atmospheric pressure at sea level. Thus, when we refer to an espresso machine operating at 9 bars, it means that water is pushed through the coffee grounds at a pressure nine times that of the atmosphere.

Manual espresso machines generate the necessary pressure for extraction using either a direct lever or spring piston mechanism.

Pressure is utilized in various brewing methods, such as the Moka pot and AeroPress. However, the pressure in an espresso machine is significantly higher. Early espresso machines relied on steam pressure, but with the introduction of electricity, most automatic and semi-automatic machines now use vibratory or rotary pumps.

Optimal Pressure for Espresso: How Many Bars Are Needed?

As you may know, creating the perfect shot of espresso involves several key factors: brew ratio, brew time, and brew temperature. Other elements, such as grind size, water pressure, and tamping pressure, also play crucial roles as they directly affect these primary variables.

Higher pressure results in faster coffee extraction from the grounds. In theory, increasing the pressure could lead to a quicker cup of coffee. However, there’s a reason the recommended extraction time for espresso ranges between 25-30 seconds. Even with significantly increased pressure, a 12-second espresso shot would not provide a satisfying experience.

It’s the harmonious balance of all these factors that truly matters. Considering all the components that contribute to a great espresso, nine bars of pressure have been identified as the optimal level. This balance ensures that the extraction process is neither too fast nor too slow, allowing the flavors to fully develop and produce the rich, aromatic shot we enjoy. By maintaining this balance, you achieve a well-rounded and flavorful espresso that meets the high standards of both amateur enthusiasts and professional baristas.

Comparing 9 Bar and 15 Bar Espresso Machines

If 9 bars is the optimal pressure for brewing espresso, you might wonder where 15 bar coffee makers come into play. Many home machines advertise their ability to produce 15 or even 18 bars of pressure, suggesting that higher pressure is better. However, the reality is that cheaper espresso machines often lose significant pressure between the pump and the group head. So, while they may initially reach 15 bars, the actual brewing pressure is typically around 9 bars.

Interestingly, many high-quality espresso machines feature a valve designed to prevent brewing at pressures exceeding 9 bars. This ensures a consistent and ideal extraction process, aligning with the recognized standard for creating the perfect espresso shot.

Is 6 Bars Of Pressure Sufficient?

The emergence of Third Wave Coffee has led to innovative espresso-making techniques. Among these advancements is the turbo shot espresso, which utilizes 6 bars of pressure, a 1:2.6 ratio of medium ground coffee to espresso yield, and a 15-second extraction time. This method offers a unique approach to brewing. For more information on turbo espresso shots and how their flavor profile compares to that of traditional espresso, continue reading.


In summary, the ideal brewing pressure for a great espresso is around 9 bars. However, when purchasing a new espresso machine, don’t be overly concerned with the advertised pressure levels. For those interested in the technical aspects of brewing, seek a machine with adjustable pressure settings and a pressure gauge for precise control.