Why Heat and Pressure Determine Espresso Quality

If you’ve ever made coffee, you know that you put water into the top of the machine, the water gets heated, and then it gets pushed through the coffee grounds to drip out some delicious java. It requires a little bit of time, but it’s a pretty simple process. It’s pretty much hot water and time, there isn’t a lot to it.

For espresso, however, you need more. You not only need the heat that gets put into the coffee, but you also need an amount of pressure you aren’t going to find in a regular coffee maker.

There is far less actual solid material used to make espresso, so it takes a bit more work to get the flavor out of the beans and grounds. If you were to just push hot water through them, you might get something that tastes like watered down coffee, but you would be really short on the flavor that actually makes the drink worth drinking.

That’s Where The Pressure Comes In

As I said, the hot water just isn’t enough. That’s why you’ll notice most espresso machines come with an extra boost of pressure, which makes the difference between cafe water and an actual espresso. So it’s not the type of coffee that matters, it’s the way it is brewed.

The pressure makes all the difference here. You grind the beans and then “tamp” down the grounds. You basically make a disc out of the grounds, and they get compact and dense. Then the heated water goes through the grounds with the pressure that is required to, basically, break through the disc and pull all the flavor out of the grounds.

Higher pressures means more intense flavors, but too intense isn’t good either. Around 9 bar is the best pressure rate for extracting espresso, but because most home espresso machines use so called vibratory pumps instead of professional grade rotary pumps, they need more than that to actually have that magical number when the water reaches the grounds. That’s why most home espresso machines come with 15 bar pumps.

Another Thing To Keep In Mind

When you’re choosing between the high end and low end espresso makers, you have to remember that what’s just as important as pressure is the ability to maintain the pressure over time. Less expensive machines may be able to make the espresso quickly or passably, but the only way to get consistent flavor is to use a machine that can maintain the 15 bars of pressure it claims to get. Without it, you won’t be able to get that much good espresso from the machine.

You probably won’t notice the difference between consistently pressurized and poorly pressurized espresso if you aren’t terribly particular. It won’t necessarily be bad, it just won’t be consistent over time. If you’re like me and know your espresso pretty well, you may be disappointed with the taste of something that didn’t pull all the flavor out of the grounds. It’s not that it can’t be good, it’s just that it won’t taste exactly right.

So How About Temperature?

Any espresso machine that brews with anything other than just steam has a boiler, which is how the water gets hot enough to make the espresso you’re after. The boiler heats the water up and then the water is pushed through a pump. The pump takes the already hot water and creates the pressure to push it quickly and thoroughly through the grounds.

Next stop is the cup, and there have been many discussions about what temperature the brew should be here. True aficionados drink their coffee the moment it’s served, as hot as possible, because the roast flavor will be at its purest. Lower temperatures allow other flavors to come to the foreground, and the brew will be milder.

Other factors matter as well, and some blends actually taste better at lower temperatures, but the most important factor is YOU. It’s good to know that temperature matters, and it’s good to know that the optimal temperature depends on the blend, but only you know how these factors combine with your taste.

Warm Up To The Idea

If you’re not an espresso snob like I am, you can save yourself some money and heartache by going ahead and ruling out the super expensive machines that come close to absolute perfection, and look at more moderately priced models. There are a ton of really good machines that don’t cost an arm and a leg, so you’ll still have one heck of a search to find the perfect machine for you.