5 Surprising Reasons Why Espresso Is So Strong

Espresso is a tiny cup of coffee that packs a big punch and that little bit of liquid will certainly wake you up. But why is it so strong?

Espresso is a brewing method that creates a very intense-tasting, thick liquid that’s served in small cups. The reason for this strength is that a lot of grounds are extracted into a small amount of water. This is done by using a lot of grounds, grinding them very fine, and extracting them under pressure.

Let’s look at the different factors and how they influence the strength of espresso.

Why Is Espresso So Strong?

Espresso is one of the strongest types of coffee you can find. But why is it so strong? We’re talking about taste here but the reasons why espresso is high in caffeine are the same as for why the taste is strong. With 60-90 mg of caffeine per shot of espresso, it is very high in caffeine as well as very strong tasting.

Espresso isn’t quite the strongest type of coffee, ristretto takes that crown. However, espresso is the strongest coffee that is commonly drunk.

There are three main reasons why espresso tastes so strong:

  • Ratio
  • Fine grind size
  • High Pressure
  • Dark Roast
  • Robusta

It can all be summarized as a very fast and efficient extraction. Much faster and more efficient than other brewing methods like pour-over.

Suggested: What do you need to make good espresso at home?

Let’s take a look at those factors in detail.

1. Ratio

The first reason espresso is so strong is that it uses a lot of coffee grounds for the amount of liquid that ends up in your cup. A single shot of espresso is about 28 grams of liquid but about 14 grams of coffee grounds is used to brew this. That is a 1:2 ratio (one gram grounds for every two grams in the cup). For reference, pour-over coffee uses a ratio of around 1:15.

That alone means there are much more coffee grounds available for every milliliter of water than for a pour-over. You probably have noticed that pour-over or drip coffee is much more diluted compared to espresso.

The strength of coffee is mostly decided by how much of the coffee bean you get into the water. If you can get more into less water, it’s stronger.

Also, the amount of caffeine you get in a cup is largely decided by the amount of coffee you use. Caffeine is very easily soluble in water so pretty much any contact with water will extract the caffeine. So even if not all the taste of coffee is there, you’ll probably still have a lot of caffeine in espresso.

Suggested: Espresso machine ratio

2. Fine grind

However, because you have so many coffee grounds for so little water and you want to extract that coffee in a short amount of time (about 25-30 seconds), you need to make the extraction very efficient and quick.

A pour-over takes about three minutes while pulling a shot of espresso only takes about 30 seconds. That means the water gets more time to hang out with the grounds with a pour-over and therefore more chances to extract the grounds. However, for pour-over and most other brewing methods, the grounds are much coarser than for espresso.

The espresso grounds are much finer than for pour-over. That means there is more surface area for the same amount of coffee grounds. More water can interact with the grounds at the same time which means the extraction is much faster and can be done with less water. If you put more of the coffee bean in less water, it will be much stronger.

Finely ground coffee for espreso

3. Pressure

To help extract all of the coffee grounds in such a short time with little water, you’re going to need a little more than just a fine grind. Pressure is what makes espresso the strong, intense, and thick drink you know and love.

Espresso is brewed by pushing hot water through the coffee bed at about 8-9 bar of pressure. This pressure pushes helps the water penetrate the coffee grounds much faster and squeeze the coffee out of the filter. The pressure also helps speed up the extraction in other ways.

Suggested: Should you get a 15-bar espresso machine?

4. Dark roast

While over the last few years, things have been changing, traditionally espresso has been brewed with a dark roasted coffee. That dark roast does two things:

Roughly speaking, the darker a coffee bean is roasted, the more bitter notes come out. While the bitterness is not a good indicator of overall strength, the bitterness is what most people associate with strength. However, caffeine is one of the first things to dissolve in the brew water and the very bitter notes come later so they aren’t really related.

The second reason is that darkly roasted beans are easier to extract. Darker roasted beans are drier and more porous making extraction easier. Dark roasted beans also break up easier so grinding them will result in more coffee dust known as ‘fines’. Those are very small particles that therefore are very easy to extract but also cause bitterness.

5. Robusta

Sometimes there is a little bit of Robusta mixed into the Arabica that’s usually used for most coffees. Robusta is higher in caffeine (almost double Arabica) and usually has a stronger taste. This contributes to the strength of espresso.

The caffeine is not the most important reason Robusta is often added though. It’s often added because you get more crema (foam on top of the espresso) by doing so.

Coffee extraction

So you might notice that all the things above have to do with extraction. To really understand why espresso is so strong, it’s good to understand extraction.

Coffee beans are made up of materials that are soluble in water and materials that are not. We want a lot (but not all) of the water-soluble in our cup of coffee while keeping out the insoluble parts. The soluble parts in the water is what makes coffee coffee. The insoluble materials just show up like residue or sludge in your cup which you don’t want.

espresso coming out of a portafilter without spout
The first liquid of an espresso shot is full of soluble material and is quite thick.

You don’t want to extract all the soluble material either. The trick of brewing coffee is to get the right amount of solubles out of the coffee bean while not overdoing it and keeping the grounds out of your coffee cup. The amount of solubles you get from the coffee grounds is called extraction.

So to get the right extraction, an amount of work has to be done. This work is done by the water. You want to get the soluble materials and water is the solvent. If you see the coffee grounds as a gold mine, the water is the miner. The miner takes the materials you want into your cup. If you want more from your gold mine, you’ll either need more miners or one miner to work more efficiently.

Getting back to coffee, you either need more water or make the water extract the grounds more efficiently through higher temperature, smaller grind size, and higher pressure.

Higher extraction isn’t always better though. In general, if you over-extract, you went too far and the coffee will taste very bitter. Under extract and you’ll get very sour, acidic coffee. Because all the soluble compounds are dissolved at different rates, some compounds are extracted earlier and easier than others. And the compounds that make coffee sour are usually released first and the very bitter ones last.

Getting the correct balance of extraction is the key to good-tasting coffee. While there are methods of measuring the exact extraction, they are out of reach for most people and not really important. In the end, it’s about the taste. If you like the taste of your brew, that’s all that matters. Understanding extraction just helps you gain the knowledge to improve your coffee.

Recommended Espresso Equipment

Besides an espresso machine, there are a few other tools that can make your espresso better. Here are my favorites:

  • Espresso Machine: The Breville Barista Express (Amazon) is the sweet spot in price and quality for most casual home baristas. It comes with a built in grinder and most tools you need to brew espresso.
  • Tamper: A nice tamper helps you tamp your grounds in the filter for the best result. Any correctly sized tamper can do the job but a nice heavy one just feels so much better in your hand than a plastic model. This Luxhaus one (Amazon) has a nice trick up it’s sleeve to make tamping very consistent.
  • Beans: Good espresso starts with good beans. Using fresh beans is a big improvement over pre-ground coffee.
  • Scales: Getting consistently good espresso means you have to know how much grounds is going into the machine and how much is coming out and how long this takes. A coffee scale is going to make your espresso much more consistent and also makes adjustments a lot easier. The Apexstone coffee scale (Amazon) is cheap and doesn’t look too sleek but is just as accurate as more expensive scales. The TimeMore scales (Amazon) look and feel a lot nicer but cost a bit more.
  • Distribution tool: After grinding you can get some clumps in the coffee grounds. Those clumps should be broken up so the water can extract all the coffee grounds equally. Distribution tools are very simple things but this one (Amazon) is beautifully made and will look good in your kitchen.


Welcome to CoffeeImproved! Since falling in love with coffee, I've been on a journey to improve my morning cup day by day. That means I've tried many different brew methods, beans and equipment and experimented with all of them to find what I like. This is where I share what I've learned with you.

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