Espresso is probably the most engineered form of coffee. But have you ever looked at the machine carefully to understand the mechanism of a perfect shot of espresso? If you have, you know there are several variables that function simultaneously for a consistent taste and flavor.
And the most important being the pressure. Yes, the wrong pressure setting is likely to give you a lousy espresso experience. Check out our guide on how to adjust pump pressure on espresso machine and learn about the key to great, consistent coffee shots.
Understanding Pressure on Espresso Machine
If you are very fond of coffee and can’t start a day without it, we would recommend you to know the mechanism behind it, instead of just complimenting how great the shot is. As you learn about the factors behind it, you can be a pro in the field and experiment with the beverage at your home.
So, one of the fundamental things in an espresso machine is pressure. It’s also a vital component of the shot to retain the most flavors out of the coffee and deliver consistency.
Let’s start with how espresso is made. The concentrated coffee shot is made by passing boiling water under a definite pressure through the finely ground beans.
The hot water dissolves the ground beans, and the pressure passing of water extracts the taste and flavor out of it and sometimes gives a golden crema on top of the brewed espresso.
And how a machine generates and maintains pressure? Whether the machine is a high-end one with many pressure and adjustment capabilities or a regular one, generating pressure comes down to two key components — the pump and the resistance.
The pump generates the water flow, and passing it through some kind of resistance creates the pressure. And the amount of pressure depends on both.
Resistance is created either by restricting the outflow diameter, like using narrow tubes or jets or pump regulation of pressure. With the increased restriction, the machine performs harder to maintain the outflow. So, it also determines the brewing time.
Now, what is the pressure benchmark? Usually, 8.5 to 9 bars is considered a standard for maintaining consistency. Within this range, it takes about 30 seconds to extract a double espresso, which is 60mls.
Types of Pumps Used in Espresso Machine
One thing that has to be noted is, regulating the force is not entirely up to the machine. The components and restrictions in a machine are most of the time not sufficient to provide such robust pressure. This is where the pump comes to play, and it manipulates the flow rate to deliver the high-end force.
Once, the espresso machines used to generate the water strength manually by pulling large levers with pistons. Nowadays, modern machines switched from manual to electric.
And electric pumps come in two categories- rotary pumps and vibratory pump.
It is a mechanical pump with a somewhat complicated mechanism. They come in a larger size; however, they operate quietly. The larger size makes it harder to replace, but having a longer life span, replacement needs come rarely. These pumps are usually used in coffee shops.
Vibratory pumps are electric ones with a simplistic mechanism. They are smaller in size and cheaper than the rotary pumps. The size and price make it easy for replacement, as they last about 5-6 years. Suitable for both home and commercial use; however, it produces large sounds.
How to Adjust Pump Pressure on Espresso Machine?
Adjusting the pump pressure is not very challenging if you are familiar with the device and the procedure. Most modern machines come with high-end configurations to adapt and to change pressure accordingly.
However, below are the simple steps to adjust the pressure if you are using a complex rotary pump.
Unplug the Machine
Don’t just start making the adjustment by turning the machine off. You need to unplug it fully.
Find the Adjustment Screw
To get to the adjusting screw, you need to remove the top panel, unscrewing three screws from the front panel. You may also have to lift off the outer shelf, and for that, five screws have to be removed.
Adjust the Pressure
Now rotate the screw using a screwdriver anticlockwise or outward for reducing the pressure. And for increasing, rotate it inward or clockwise.
Check if It Is Optimum
The standard benchmark is the nine pressure bars or 130PSI. Check on the machine’s gauge if you have reached the benchmark. Once the desired pressure is obtained, your machine is now good to go.
Another important consideration that you should keep in mind is that the inlet pressure of the pump should be about 25PSI.
Related Article: How to Install Water Softener with Espresso Machine
Why Do You Need to Adjust Pump Pressure on Espresso Machine?
The question may naturally come to your mind, why is it so important to maintain standard pressure. Although the water strength is not the only variable to determine the shot’s quality, it is a vital one. And without proper adjustment, the machine may end up generating too much strength or too little.
Let’s what happens when the force is too high and too low.
Generally, a pressure above 9.5 bars is regarded as too much. A higher bar also means it takes a greater time to brew the coffee, resulting in a very bitter tasting concentrated acidic shot.
If the water gauge is showing below 8.5 bar, it means the pressure is too little. At a lower bar, water passes fast and easy, reducing the extraction time. Which, in turn, results in a sour-tasting shot.
If you’re having problems with your machine holding the pressure, there is a simple workaround to it. In this article, we went through several steps on how to adjust pump pressure on espresso machine. Follow our step-by-step guide, and you will never have to miss a cup of coffee in the morning.
Recourse: Rotary Pump Pressure Adjustment – espressoparts.com