Espresso Brew Pressure Guide
What is Brew Pressure, and Why Does it Matter?
Brew pressure in espresso is one of those topics that can start a lot of debate.
Traditionally, 9 bars of pressure has been seen as the gold standard for espresso extraction, but as we'll see, there's a lot more to it than just sticking to one number.
When you hear "9 bars," that's referring to the pressure applied by your espresso machine to push water through the coffee puck.
But is 9 bars really the be-all and end-all?
Recent discussions and experiments suggest otherwise.
Key Takeaways
9 bars isn't always the golden rule: While 9 bars of pressure is traditionally recommended, different pressures can yield varied and sometimes better results.
Static vs. Dynamic Pressure: Static pressure (measured with a blind filter) is often higher than the actual brew pressure experienced during extraction.
Lower pressures can shine with single origins: Some lighter, more nuanced coffees can benefit from lower pressures, offering more clarity and balance.
Adjusting pressure isn't always necessary: Manufacturers often set machines to optimal pressures for a reason, so you may not need to tweak much.
Static vs. Dynamic Pressure: A Quick Primer
When you're measuring brew pressure on your machine, you might be using a gauge, either built-in or on a special portafilter.
However, it's important to distinguish between static and dynamic pressure.
Static pressure is what you measure when you have a blind filter in place—basically, you're blocking the water flow, so the gauge reads the maximum pressure your machine can build.
This is usually higher than the actual brew pressure.
Dynamic pressure, on the other hand, is the pressure your coffee experiences when water is flowing through the puck during an extraction.
As Mark from Whole Latte Love explains, static pressure might read as high as 12 bars on some machines, but the actual brew pressure could be closer to 9 bars.
The Case for Lower Pressure
Many modern espresso machines allow you to adjust brew pressure, and some baristas swear by using lower pressures for certain types of coffee, especially lighter, single-origin beans.
In a video from Sprometheus, different pressure levels from 9 bars all the way down to 3 bars were tested, revealing that lower pressures can sometimes produce better results.
For example, shots pulled at 7 bars showed excellent balance, sweetness, and a clean finish, especially for single-origin coffees.
Conversely, shots at very low pressures like 5 bars were often too sour and lacked complexity.
Should You Adjust Your Machine's Pressure?
Before you start tweaking your espresso machine, consider this:
Manufacturers often set their machines to optimal pressures for a reason.
Adjusting brew pressure may not be necessary and could even lead to more frustration than improvement.
That said, if you love to experiment and fine-tune every variable, adjusting pressure could open up new flavor profiles, especially if you're working with a high-quality grinder and fresh beans.
Just remember that adjustments should be made with the machine fully warmed up, as the pressure can increase slightly with temperature due to thermal expansion.
Final Thoughts
Espresso brew pressure is more nuanced than simply setting your machine to 9 bars and calling it a day.
Depending on your coffee, your machine, and your personal preferences, experimenting with different pressures can yield surprising and delicious results.
Further Reading
Feel free to explore these resources for a deeper dive into the intricacies of brew pressure and how it impacts your espresso experience.