Espresso Machine Pressure: What It Is and Why It Matters

Espresso is perhaps the most precise coffee drink you can make.

And while every step—from grinding to tamping—plays a role in brewing the perfect espresso, one thing is often overlooked: pressure.

Without the right pressure, even the best coffee beans won’t come out to their full potential. It’s like trying to make a good pancake without applying the right heat—you’ll get something, but not what you want.

In this article, we'll discuss the importance of espresso machine pressure: what it is, why it's so crucial, and how it affects everything from the taste to the texture of your coffee.

You'd be surprised how much pressure affects that perfect cup of coffee.

So, get ready—let's talk about why 9 bars is the magic number.

Why the right pressure is so important.

1. Extraction efficiency

The 9 bar standard ensures that water is evenly passed through the coffee, extracting the full flavour of the beans.

If the pressure is too low, the water will simply seep through, resulting in a sour, over-extracted espresso. If the pressure is too high, the water will be forced through the coffee too quickly, resulting in over-extraction and a bitter taste.

2. Crema formation

Pressure is what gives espresso its signature crema—the golden, foamy layer that tops a well-brewed espresso.

The right pressure helps emulsify the coffee oils, creating that smooth, rich crema that adds both texture and flavor.

Without enough pressure, your crema will be thin and weak and your espresso will taste flat.

3. Consistency

Consistency is key when making espresso. The 9 bar standard ensures that every espresso is prepared with the same extraction force.

Machines that fluctuate in pressure can result in uneven shots, with some under-extracted and others over-extracted.

How does pressure affect your espresso?

The pressure setting on your espresso machine affects a few key factors during extraction:

1. Throughput speed

At 9 bar, the flow rate of water through the coffee grinds is balanced—not too fast and not too slow. If the pressure is too low, the water flows too slowly, causing the coffee to be under-extracted.

Too much pressure and the water moves too quickly, resulting in a watery, acidic espresso.

2. Pressing (Tamping)

The way you press the coffee works in conjunction with the pressure.

When you press the coffee evenly and with constant force , you create a uniform coffee layer through which the water can flow easily.

If the coffee is tamped unevenly or too loosely, the water will flow more easily through some parts than others, leading to channeling and uneven extraction. This is why tamping is just as important as the pressure itself.

3. Machine calibration

Not all espresso machines are the same. Some machines allow you to adjust the pressure manually, while others have a fixed setting.

Professional machines in cafes often have more advanced pressure regulation, allowing them to maintain consistent pressure throughout the extraction.

At home, you may need to experiment with your machine's settings to find the right pressure.

How do you adjust the pressure on your espresso machine?

If you're using a high-quality espresso machine, you can adjust the pressure to fine-tune your shots.

However, most home machines are set to around 9 bar. Below we explain how you can experiment with the pressure and get the most out of your machine:

1. Adjust the grind size

A finer grind requires more pressure to force the water through the coffee, while a coarser grind allows the water to pass through more easily. If your shot is coming out too fast or too slow, adjusting the grind size can help regulate the pressure.

2. Pressing technique (Tamp technique)

Make sure to tamp the coffee evenly with enough force (about 13-14 kg) to create a uniform coffee layer. Inconsistent tamp can cause problems with the water flow, resulting in uneven extraction.

3. Machine settings

Some espresso machines have a pressure gauge or pressure adjustments. If your machine has this feature, you can adjust the pressure to see how it affects your shots.

Remember that more pressure isn't always better—aim for a balance that produces a well-rounded shot.

How much pressure is too much?

When it comes to pressure, more doesn’t always mean better. Many espresso machines are set to 9 bar of pressure, and for good reason—this is the sweet spot for extraction.

While some professional machines can reach 10-11 bar, most home machines are optimized for 9 bar.

If you set the pressure too high, you may end up with an espresso that is too bitter and the crema may collapse.

It's like trying to put on your favorite pair of jeans after a feast – sometimes, less is more…

Conclusion

The pressure of your espresso machine is an important factor in brewing a great espresso. The right pressure ensures that the coffee is extracted evenly, resulting in a balanced shot with a rich crema and great flavor.

If you're looking for consistency, precision, and quality, understanding how pressure works will help you brew better espresso.

So, the next time you’re brewing, remember: it’s not just the beans that matter—pressure plays a role, too! After all, with espresso, it’s the pressure that makes the magic happen.