How many bars for espresso? The average coffee drinker has no idea what a bar is, much less how this measurement can affect the quality of your espresso. This post is designed to fill up this all-too-common knowledge gap.
A perfect shot of espresso is the result of different aspects coming together perfectly to create a unified whole. As a coffee lover, you might already be familiar with some of the things that need to come together to create that perfect cup of espresso.
High-quality, dark-roasted coffee beans? Check.
Reliable espresso machine? Check.
Skilled barista? Check.
However, there are factors playing behind the scenes that are just as important when it comes to making espresso. Of these factors, one of the most critical is pressure.
What is a Bar, Anyway?
Before you can figure out how many bars is just right for espresso, you have to know what a bar actually is. In the context of making espresso, pressure is important because it measures the amount of energy required to force hot water through the coffee grounds during the extraction process.
Pressure is measured in barometric pressure, or “bar” for short. A bar is the weight of air at sea level, as well as the force exerted by the atmosphere. The higher the bars, the more force is exerted.
Espresso Machines and Pressure
Espresso machines need to exert a certain number of bars to extract espresso properly, and this is where the conversation gets tricky. Why? Because there’s no definitive number for how many bars for espresso is the perfect amount.
Typically, most espresso makers will exert around 9 bars of pressure. This is equal to nine times the pressure exerted by the atmosphere. This might not sound like much, but let’s put that into perspective:
Think about your car. A typical sedan’s wheels require around 30 PSI each, or pounds per square inch. In contrast, the 9 bars exerted by an espresso machine measures at about 130 PSI, or more than four times the amount exerted by the air inside a tire.
However, some say that 15 bars is the perfect amount of pressure to completely extract the flavor and aroma for an espresso.
Here’s the thing: there’s no definitive way to decide which number of bars work best for extracting espresso. Mostly it’s just a matter of personal preference.
Types of Espresso Machines
There are three types of espresso machines in the context of how the machine applies pressure.
- Levers – also known as piston machines, these are the traditional way of adding pressure to your espresso shot. Today, lever machines can still be found in high-end boutique coffee shops that have a skilled barista who knows how to operate them. The lever allows you to manually adjust the amount of pressure you put for maximum customization, but only a practiced hand can use a lever machine properly.
- Steam power – this type of pressure exertion system can be found in most home-level machines and lower-end commercial models. The steam boils the water, allowing the steam to push through the grounds to pull the shot. However, this method is not powerful enough to extract the crema from the grounds.
- Pump machines – pump machines are the most common type of espresso machines used in coffee shops. Some higher-end models allow you to tweak the settings such as temperature and number of bars. While it is consistent and reliable, it does have a learning curve for beginners.
Other Factors that Affect Your Espresso
Pressure alone does not dictate the final quality of your espresso. Simply increasing or decreasing the number of bars isn’t enough to determine how well a certain pull of espresso will turn out. Aside from pressure, there are two other factors you need to keep in mind: time and heat. Together, these three factors will ultimately determine whether you’ve succeeded in making espresso.
In general, the more pressure you exert, the less time your coffee grounds have in contact with the hot water during the extraction process. Thus, you want to have the right amount of time for the water to extract flavor, but not too much that the coffee becomes bitter.
Typically, an espresso shot takes anywhere between 20-30 to pull, but the exact time may vary depending on the grind size, the compactness of the puck, and yield preference.
As with time, the balance between heat and pressure is critical. You want to use enough heat so that the soluble oils in the grounds dissolve into the water, but not too much that your coffee turns bitter.
According to the Specialty Coffee Association of America, the optimum brewing temperature for espresso is between 195⁰ to 205⁰F or 91⁰ to 96⁰C.
Pressure Makes the Crema Rise to the Top
Okay, so that’s not the saying, but for this instance, we tweaked it just a little bit.
One of the best ways to know if you have a good quality espresso is when you’ve extracted the crema. This is the luscious golden-brown cream on top of your espresso. It is produced from the oils that you’ve extracted from the grounds.
Not only is crema beautiful to look at, but traditionalists also say that it’s the best part of the espresso experience because of the concentrated flavor.
The only way to extract crema from beans is by having a machine that can produce 9 bars of pressure or more.
Can You Really Make a Barista-Quality Espresso at Home?
This is where it gets a bit tricky for home-quality espresso machines. While it’s fun to experiment at home and play with models that have all those nifty features like milk frothers and programmable brews, most home-quality espresso machines don’t have what it takes to make a café-grade espresso.
There are so many machines out there that promise 9 or even 15 bars of pressure at an insanely low price point, but most consumers don’t really know whether they’re getting the real thing. Even if they do produce the advertised number of bars, there’s no guarantee that the machine will keep it up for the duration of the whole shot.
How Many Bars for Espresso?
At the end of the day, there’s no way to settle the debate between over how many bars for espresso should be applied. While the industry standard is 9 bars, some say 15 is the sweet spot. Whichever the case, the important thing is to be able to make your cup of espresso that you genuinely enjoy.