Last Updated on September 25, 2024 by Brian
How does espresso machine work?
An espresso machine seems like one of the most complicated pieces of kitchen equipment to use, but once you know the science behind the process it’s really quite simple. Read on to learn more about how an espresso machine works and why it makes perfect coffee every time!
The Science of Espresso
Every time you order an espresso drink, you’re actually ordering one part art and one part science.
The art comes from the barista behind the counter, who uses their training and expertise to ensure that your drink tastes exactly as it should; they carefully measure the coffee beans and water, tamp them with just the right pressure, brew at just the right temperature, finish with just the right amount of foam on top, and more in order to create your perfect cup of coffee.
What is an Espresso Machine?
An espresso machine is a device used to brew coffee. It’s called an espresso machine because espresso refers to its powerful taste, not its speed (which isn’t very fast at all, by design).
When you press a button or turn a knob on your espresso machine, it heats water to somewhere between 194 and 204 degrees Fahrenheit and forces it through finely ground coffee at 9 bars of pressure.
A person trained in making espressos will tinker with these two factors until they’re happy with how their beverage tastes. This tweaking process is called dialing in, or dialing for short. The best way to learn about dialing is from someone who has been doing it for years and knows what they’re doing.
Step 1 – Heating the Water
There are two main types of espresso machines: pump driven, and pressure assisted. In both cases, water is heated in a boiler to between 195 and 205 degrees Fahrenheit.
The water then passes through a group head, into which your coffee grounds are placed. The group head contains a pipe shaped like a showerhead that evenly distributes water over the coffee grounds for maximum extraction (this is what we mean by pressure assisted).
Pump driven machines use steam pressure instead to create even pressure across all of your grounds. This will give you what is often called crema on top of your espresso—the rich foam that makes café lattes look so good!
Step 2 – Maintaining Temperature
Temperature is perhaps one of most important factors in making a quality espresso. The optimal temperature to extract flavor and aroma from coffee grounds is 195-205 degrees Fahrenheit as mentioned before.
Achieving that with your typical home coffee machine can be tricky without some expert tips. First, take note that if you’re using a simple drip brew coffeemaker, it may not maintain that optimal temperature range – even though it’s designed to make coffee!
In such cases, we suggest moving your grounds through as quickly as possible by increasing your grind size. You should then place them in water for about 30 seconds before bringing them to your machine for brewing.
This quick rinse will help get rid of excess oils on the surface of your grounds which may affect extraction later on.
Step 3 – Extraction
Since espresso uses extremely fine grounds, a good deal of pressure is required to force water through them. This happens during extraction—the term used to describe what happens when water comes into contact with coffee grounds and begins to flow out from a single hole at the bottom.
Water is forced through that hole because there’s so much pressure on it from behind (at 10 bars, or about 150 pounds per square inch).
It’s amazing enough that anything could push hard enough to shoot something as dense as water through a tiny hole like that—but it gets even more incredible once you realize that it does all that in 20-30 seconds.
Step 4 – Resulting Coffee Drink
What you get in your cup isn’t just a few jolts from caffeine. While it takes about 20 seconds for your coffee to go from beans to your cup, there are about 800 chemical reactions that take place along that route.
As one coffee scientist told NBC News, It’s like a magic trick — you can see something but can’t quite understand how it works.
These reactions have everything to do with what goes into your cup and what comes out (and why). There are three main players in this process: (1) water, (2) espresso grinds and (3) milk or other milk substitute.
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