Why Is Achieving A Level Tamp Essential For Proper Water Flow?

Ever wondered why your espresso suddenly gushes from one side of the portafilter like a firehose?

Channeling is one of those things that every home barista hits eventually and when it shows up, it shows up hard. One side of the puck goes untouched while the other gets flooded. You’ve got bitter coffee, under-extraction, and a crema that just doesn’t want to show up. It’s frustrating and most of the time, tamping is to blame.

There’s no sugar-coating it: tamping mistakes ruin espresso. But fixing them? That’s totally possible. And once you do, you’ll probably wonder why you didn’t try sooner.

What channeling actually looks like

Before anything else, it helps to know what channeling is doing to your shot. If you're using a bottomless portafilter, you'll notice water aggressively spurting from just one spot. That’s because the water has found the path of least resistance through your puck probably a pocket or weak side and it's completely ignoring the rest of your coffee bed.

This means your espresso is under-extracted in some places and over-extracted in others. And it’s all happening in one pull. No amount of great beans or temperature control is going to fix that unless the puck is prepped properly.

Here's an article that lays out the long-term problems channeling creates.

Not distributing evenly before tamping

This is probably the most common mistake I see. People grind, dose, and immediately tamp without bothering to stir or settle the grinds. The result? Massive inconsistencies. There are pockets of air in there, clumps of fine particles, and zero chance of a level extraction.

Once I started using a wdt tool, that changed completely. Even just a few seconds of distribution makes the grinds settle evenly and gives your tamper something uniform to press against.

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Without that, you’re essentially tamping a puck full of potholes and fluff.

This article digs into how bad distribution almost always leads to channeling, especially with lighter roasts.

Tamping on an angle or with inconsistent pressure

I’ve seen so many people tamp on a bench that’s too high or low for them, arms awkwardly bent, tamper tilting slightly. Even if it feels like you’re pushing straight, the smallest angle sends water diagonally through the puck creating a shortcut to channel city.

That’s why I now swear by using a self-leveling tamper. It eliminates the guesswork. The base levels itself as you press down, meaning you don’t have to stress about technique every single time.

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This breakdown explains why even slight tilts in tamping pressure can result in micro-cracks in your puck.

Using the wrong basket size or portafilter

If you’re trying to tamp 18g into a 22g basket, that puck’s gonna be too shallow and it’ll barely hold shape. Same goes if your tamper doesn’t match the basket diameter. You’ll end up with edges that are barely compacted or centre-heavy pucks that channel through the sides.

That’s where getting a precision basket or a properly fitted tamper for your specific machine size makes all the difference. I’ve got mates using 51mm baskets on a machine designed for 58mm, and their shots were spraying like fireworks. Fixing the fit fixed their shots.

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Not adjusting tamp based on your dose

This is one I learned the hard way. If you’re changing your dose but tamping with the same pressure and technique, you’re setting yourself up for uneven shots. A 16g puck doesn’t behave the same as a 20g one.

Every change in dose calls for a fresh look at your puck prep and that means looking at height, density, and tamp resistance. What I’ve seen is that many home baristas dose too little, tamp too hard to compensate, and crack the puck in the process.

Start with a consistent dose that suits your basket, and go from there. Using dosing tools or rings helps prevent the overflow or under-dose mistakes that create this trap.

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This guide walks through how dose size directly affects tamping and extraction balance.

Neglecting your tamper

It sounds silly, but a dirty or uneven tamper can sabotage you without you even realising it. Grounds get stuck to the base, build up over time, and suddenly you’re tamping at an angle or with a rough surface. I keep a soft cloth next to my station and give the tamper a quick wipe before each use. It’s a small move that makes a big difference.

Not using a tamping station or stable surface

If your tamping surface is wobbly or angled, your puck is going to be affected no matter how good your tamper is. A simple tamping station adds consistency. It levels the portafilter, absorbs force, and gives you confidence in your press.

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Bonus tip Watch your shot

This isn’t directly about tamping, but if you’re not watching your shot through a bottomless portafilter, you’re missing all the clues. Channeling doesn’t hide well. If it’s happening, you’ll see that wild spray, blonde striping, or quick drips down the edge of the handle. That feedback helps you tweak your technique.

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Here’s another article that breaks down what you should look for in a problematic shot.

Final thoughts and next steps

If you’re still struggling with channeling, don’t bin your beans or blame the machine. Tamping is often the hidden culprit. It’s usually one or two small habits that are throwing off your shots and they’re all fixable.

Start with your prep. Grab a distribution tool, level out your grounds, and make sure your tamper fits your basket properly. From there, a consistent press on a stable surface goes a long way. And if you need help, just reach out to us through our contact page.

You can also check out our selection of coffee blends to match your machine and dial in flavour once your technique’s on point.

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Written By Laurie Nance

I'm the founder of Brewedco Coffee™, passionate about coffee, coffee tools, and helping others better understand how to utilize them. With years of experience in the coffee industry, I love sharing insights on brewing techniques, choosing the right equipment, and the science behind making the perfect cup.