Why Does Coffee Need to Be Pressed? (Tamping Advice)

I’ve always tamped the coffee grounds before brewing, so it now comes as second nature. But why do we need to do this?

Coffee grounds need to be pressed or tamped so they are packed tightly together, meaning the water has to work harder to percolate through, which improves the flavor and strength of the coffee. Loosely packed grounds will make weak and tasteless coffee.

Let’s dive down into the topic of coffee tamping in more detail, and discover why we need to do it, how to do it – and what this means for the flavor of our favorite brew…

Why Does Coffee Need to Be Pressed?

Why Do We Have To Press Coffee? (Why is Tamping Important?)

An espresso shot is made by forcing water through ground coffee, at high pressure. If you simply heap the coffee grounds into the portafilter, the water will rush through it unevenly, failing to pick up that delicious flavor on its way.

Tamping the grounds creates a better mass for the pressurized water. It’s the difference between digging a tunnel in wet sand or dry sand when you’re a kid: the wet sand is more solid and easier to work with. If you pour a bucket of water into the wet sand, it takes longer to sink in. It’s kind of similar with coffee grounds.

There’s a second reason why baristas always press coffee. When the grounds are pressed, they leave a small space at the top of the portafilter. The coffee will swell when it comes into contact with the water, so this little expansion gap is really handy.

What Happens if You Tamp Too Hard?

Can you tamp too hard? We know that loose coffee grounds are a problem; but is it possible that they can become too compressed? Well, it’s not easy to over-tamp your coffee, because once the tamped coffee is flat, there’s not much more you can do. 

However, if you use poor-quality coffee, there is a chance that you can over-tamp it, and the grounds become over compacted. How does this happen?

If the grounds are too loose, the water just runs through them, taking all sorts of routes and missing out on the flavors. With too-tight grounds, the opposite happens. The water struggles to pass through, and ends up moving so slowly that the resulting coffee is “over-extracted” (bitter).

Does Tamping Pressure Really Matter?

Tamping pressure matters, because as you’ve just read, under-tamping or over-tamping leads to weak or bitter coffee. But how can you judge the right tamping pressure?

According to baristas, you need to start by applying 15 pounds of pressure to your coffee grounds, working up to between 20 and 30 pounds. This sounds much easier said than done: how on earth do you work out what 20 pounds of pressure feels like?

Try pushing your hand down on a weighing scale until it reads 15 then 20 then even 30 pounds. This gives you a very basic idea of what that level of pressure feels like.

If you ask a barista how they judge tamping pressure, they’ll probably tell you that they just know. After you’ve tamped a fair few coffees, muscle memory kicks in, and you’ll just tamp on auto-pilot.

What Can I Use Instead of a Coffee Tamper?

Need an emergency coffee and you can’t find the tamper? Don’t worry: there are other ways to make that essential coffee “puck” in your portafilter.

If you have a pestle and mortar in the kitchen, the pestle is the obvious implement as it’s basically a tamper. Just be aware that the rounded ends aren’t as effective as a flat-based tamper at creating an even puck.

However, not everyone has a pestle – but many of us have a beer bottle in our home! A narrow bottle like this makes a good alternative to a tamper. Just remember to hold the bottle upright at 90˚ to make sure the puck is as flat and even as possible.

Can You Make Espresso Without Tamping?

Well, you can technically make a shot of espresso without tamping the coffee grounds, but why would you want to? A coffee made from loose grounds can be almost tasteless.

Why is this? An espresso is made by passing pressurized water through ground coffee. The water picks up the flavors, oils, and color from the ground on its way through, drawing out everything it needs to make a delicious brew.

To extract the most flavor, this needs to happen slowly. With looser grounds, the water (and don’t forget, it’s moving at pressure) speeds through the portafilter, heading in all directions through the loosely packed grounds. When it comes out the other end, it’s barely touched the sides and carries minimal flavor.

In contrast, the puck of coffee formed by tamping provides a denser service for the water to be pushed through. It slows down, absorbing more of those amazing flavors on its route. So yes, you can make an espresso without tamping, but there really is very little point.

How Do You Tamp Coffee?
How Do You Tamp Coffee?

How Do You Tamp Coffee? (Simple Steps)

Can you learn to tamp coffee like a pro? Yes you can, and although few of us attain the speed and dexterity of the actual coffee shop barista, we can certainly make ourselves a decent espresso. 

Ideally, you have a flat-bottomed tamper, as this produces a better puck. This is the name for the flat-topped, tamped coffee in the portafilter, and when you see its shape, it’s easy to figure out why it’s called a puck.

Here’s how to tamp coffee:

  1. Place the ground coffee into the portafilter
  2. Even the grounds by running your finger across the top. The more even the grounds, the more effective the process, and the better tasting the coffee
  3. Now it’s time to tamp. You want to tamp from your body, not your wrist, as you’ll be applying pressure. Bend your elbow at 90˚ and keep your wrist straight for better control
  4. Push down on the ground with the tamper. Try to push rather than twist, and increase the pressure as you tamp. As we discussed earlier, start with about 15 pounds of pressure and work up to 20 plus. You’ll get a feel for this with practice and learn what works for you
  5. If there are any loose grounds around the edge of the puck, wipe them away. We’ve all seen the professionals tap the portafilter at this point. It’s less showy, but we say stick to a wipe – it’s less risky
  6. You now have a water-ready, perfectly tamped puck

Here’s a clear little video about improving your espresso tamping technique. The short film looks at how to make your puck nice and even, and the effect different pressure has on the final cup (spoiler: not as much as you might have thought).

Final Words: Does Coffee Need To Be Pressed?

In the final analysis, without tamping or pressing your coffee will be weak and flavorless (and nobody wants that).

So it’s important you tamp down those grounds so the water has to work harder to percolate through – bringing out all that delicious flavor as it does so.

The prospect of this is making my mouth water, so I’m off for an espresso right now! 🙂