Have you ever wondered why are there 9 bar and 15 bar espresso machines and which one will give you the better coffee? Well, it was pretty confusing for us at first as well. That's why we did our research, tried a few different models and did our coffee research so you won't have to. Let's dig in.
What Are Bars of Pressure?
Bars are metric units of measuring pressure. One bar is almost equal to the earth's atmospheric pressure at an elevation of 111 meters. This is how bars in espresso makers are measured.
To simplify metric to imperial, you should know that one bar of pressure is equal to 14.5 psi. This means that a 15 bar espresso machine produces 217.5 psi of pressure and a 9 bar espresso machine generates 130.5 psi.
All of this is important when making an espresso. As espresso is made by pushing hot water under pressure through the coffee in the portafilter of the espresso machine.
If you use an espresso machine that generates 9 bars of pressure it means that the water is forced through the coffee at 9 times the pressure in the atmosphere. A 15 bar machine would be doing that at 15 times the pressure.
Initially making an espresso was a completely manual process as an espresso machine worked by using a lever. Nowadays, though, with the advancement in technology, there are high pressure pumps in espresso machines that do this for you.
How Do They Affect Your Coffee?
How do all these bars of pressure affect your espresso though? It's not as simple as high pressure equals good espresso. It's actually the opposite and nine bars of pressure are more likely to give you a delicious espresso than 15.
The reason is that if you're pushing the water through the coffee too fast, they won't have enough contact time and not enough flavor will be extracted. This will give you a weak espresso.
The opposite is also not good. If you're not using enough pressure, your coffee will be bitter. This is because the water will be in contact with the coffee for more time, over extracting the espresso and potentially making it undrinkable.
If you're a hardened coffee enthusiast and aren't new to the espresso world, you will know that to make the perfect espresso you will want to tamp it. The pressure with which you tamp can drastically affect the taste of your coffee. This is why we offer a pressure calibrated espresso tamper now for only $39. Go and get yours now.
The perfect espresso is the one that perfectly balances the coffee grind, the pressure and water temperature. This is why if you own a high-quality espresso machine, your coffee is more likely to be strong and delicious. These machines heat the water to the right temperature and have decreasing pressure when making your espresso. This is important because as the water is pushed through the coffee at a high pressure, it's not that tightly tucked into the portafilter.
To summarize, what you need for the perfect cup of espresso is an even extraction. An uneven extraction is often caused by pressure that's too high and a low pressure can give you a burnt coffee.
What About Crema?
Many coffee enthusiasts are nuts about the crema. It's no coincidence that a thick layer of crema is considered a sign of a good cup of espresso. The way to good crema, as surprising as that might be, is lower pressure.
If you espresso machines produces 7-9 bars of pressure, you're more likely to have much crema. Additionally, this depends on the type of coffee you're using, the level of your tamping and a few more factors.
How Many Bars Make the Perfect Espresso?
So how many bars of pressure will give you the perfect coffee? There's no simple answer to that question. How much coffee you extract from your beans depends on multiple factors. As we already mentioned among these are the water temperature, the level of your tamping, coffee type and more.
If you own a high quality espresso machine, it will probably come calibrated for a higher pressure. How this is done is shortening the extraction time of coffee. This might have some negative effects on the taste of the coffee though.
After all this information you've probably come to the conclusion that a lower pressure is more likely to give you a delicious coffee and you're right. A 9 bar espresso machine is comes pretty close to giving you the perfect shot of espresso.
15 Bar Espresso vs 9 Bar Espresso
The inventor of espresso Luigi Bezzerela discovered that water pushed at 9 bars of pressure at 90-95°C (195-205°F) will give you the best cup of espresso. Why is it then that nowadays you can find espresso machines that give you 15 bars of pressure? Are they worth investing in?
The short answer is no, they're not. Fortunately they're usually cheaper and smaller than machines that give you 9 bars of pressure. You might be surprised to know that there are even 18 bar espresso machines. The way they are advertised, it's no surprise that you believe that the higher the pressure, the better the espresso.
After testing a few of these ourselves, we noticed that these machines lose most of their pressure between the pump and the group head. This means that even though on the box it says that it creates 15 bars of pressure, that's only at the start. You're getting 9 bars or less by the time your espresso comes out.
Finally, if you have set up your espresso machine correctly, you should expect to get 9 bars of pressure where it matters. There's actually a standard feature in most espresso machines that stops the machine from producing more than 9 bars of pressure.
What Types of Espresso Machines Are There?
There are two main types of espresso machines: manual and automatic. The manual espresso machines are still around and are preferred by hardcore espresso enthusiasts. They are harder to use and have a higher learning curve
A manual espresso machine won't do anything for you. You have to grind your coffee yourself, heat up the water, load everything into the machine and then pull a lever to push the water through the coffee and give yourself an espresso. They're more complicated to use as not only do you need a grinder but also you will need to pull the lever with the right amount of force to give your coffee the right amount of pressure it needs.
Now, when it comes to automatic espresso machines things get a bit more complicated. Not only do you need a higher budget if you're interested in buying one, but they are also significantly more complicated and come equipped with a boiler where your water is heated, a pump and some even with a grinder.
There are two types of automatic espresso machines: semi-automatic and super automatic.
Semi-automatic espresso machines require you to grind your whole bean coffee yourself and load it into the basket. Then you have to pour water in, pick the setting you want and wait for your espresso. While this is significantly simpler than manual machines, it still requires some input from you.
A super automatic espresso machine is a whole other story. It only requires you to load it with whole bean coffee and water, and press a button. Some machines are actually directly connected to the water supply so you'll only need to add coffee. The coffee making process starts when you select what coffee you want and press the button. Then your coffee is ground, the water is heated and in no time you get a delicious cup of espresso coffee.
Frequently Asked Questions
How Much Does a Good Espresso Machine Cost?
Good espresso machines usually cost between $150 and $300. If you want to get a pro grade machine, though, you'll need to increase your budget to the shocking $1200. These machines are usually bought for coffee shops or restaurants where they make a lot of coffee and making them faster can save a lot of money.
Is the Espresso Machine Pressure Higher than the Moka Pot Pressure?
If you've ever used a Moka pot, you probably know that the coffee made in one is very delicious and rather strong. It's not as strong as espresso, though. Even though the coffee brewing method is the same and it's essentially pushing water through coffee at a high pressure, the pressure is not nearly as high. A Moka pot only generates one or two bars of pressure, which is around 5 times less than what an espresso machine makes.
Espresso machines are not all about the more, the better. Here it's the opposite, if you have less pressure, you're more likely to end up with stronger coffee. That's why 9 bars of pressure are just enough to wake you up in the morning.
Delicious espresso doesn't only depend on the espresso machine pressure, though. You will also need to get a good tamper if you want to get the best taste from your coffee. The easiest way to tamp your coffee right is with a pressure calibrated tamper. Check out our store and get your pressure calibrated coffee tamper now.