All the focus on gear and gizmo's is well and good: just don't forget that pulling the perfect shot is an art form. Despite all the tech, great espresso requires know-how, experience, feel, and great technique - never more so than when tamping.
Dialling in micro-adjustments on your grinder may reveal previously unsung nuances in your brew. Fiddling with the pressure might better optimise your extraction. But without a solid tamping technique, none of this will matter. So read on, and we'll explain exactly how to tamp espresso at home like they do in the cafe.
What Is Tamping?
For the totally uninitiated, tamping describes the process of compacting the coffee grounds into the portafilter basket. To do this, a handheld tool known as a tamper (duh) is used - thus, tamping.
When the portafilter is then loaded onto the espresso machine and the barista (you) presses 'go', steam and water are forced through the coffee grounds, or the 'coffee puck'. Almost instantly, espresso begins to ooze from the spout/s on the portafilter into the shot glass or cup.
Tamping might seem an inconsequential part of this whole. But if you understand how espresso machines work, you'll recognise how important the tamp really is.
Why Do We Tamp For Espresso?
So, an espresso machine brews using steam and heat to force the water through the coffee grounds. As a result, espresso is brewed extremely fast, and crucially, under great pressure.
This is why the coarseness of the grind is crucial when making espresso. You probably know that you want a fine/extra fine grind, to increase the surface area exposed to water. This allows enough of the oils and aromatics to extract from the ground coffee, to produce the bold taste and rich texture we associate with espresso.
Achieving the optimum extraction is basically the whole point of espresso brewing. That's why the exact fineness of grind, the timing of the shot, the temperature and the water pressure will be tweaked and balanced by baristas to alter the rate of extraction.
Why Is Tamping So Important?
You'll need to tamp ahead of every single shot you pull - and all the good work is for nothing if you blow the tamp. When you tamp ground coffee into the filter, you are dictating the density of the medium the water and steam will be forced through.
Apply too much tamp pressure and the water will flow too slowly, creating an over extracted shot. Too soft, and the water will flow too quickly, under extracting your brew. A good barista needs to achieve an even and consistent tamping pressure - which we'll cover later.
You also need uniform density throughout the compressed puck. Worse case, you'll see channelling. An unevenly tamped puck will allow the water a path of least resistance, and it then will flow mostly through this spot.
This causes the grounds in the path of the water to pass on way more solubles and over extract, giving your coffee a sour taste. The diverted water flow will in turn cause the rest of the puck to under extract, adding much unneeded bitterness. Yuk.
So, if you're really serious about brewing, learning how to use an espresso tamp properly isn't a choice. It takes a little practice, but there's no point practising if you don't know how. We put together this tamping guide to help, whether you're just starting out, or suspect your form needs a little work.
Before We Get StartedDespite this author's earlier assertions, gear is most definitely important. I assume you already have at least some of this stuff (though props to anyone who pops out for a new espresso machine after reading):
- An Espresso Machine
- Espresso beans
- Burr Grinder With Fine
- Extra Fine Coarseness Setting
- Electronic Scales
- Espresso Tamper
- Tamping Mat
Step By Step Tamping Guide: Tamp Espresso Like A Pro
Before we move onto technique, let's think about what we need to achieve: or in other words, what we mean by a good tamp.
Compress The Grinds
We compress the grounds into a puck shape in order to remove as much air as possible from between the individual grounds. Water will always take the easy route, so the more pockets of air, the more uneven the flow through the puck. We want a uniform flow of water through the coffee grounds, and to do this we must remove as much air as possible.
Even Handed Pressure
When dosing, loading the coffee into the basket, and whilst tamping the grounds, it is important to be mindful that we need both an even distribution and density. The basket should be loaded evenly, and tamped evenly so the density throughout the puck is as close to uniform as possible.
Any inconsistencies will lead to uneven extraction at best, and channelling at worst. We need good distribution and even pressure.
A Flat Puck
The top of the puck should be as flat as possible. Any uneven areas can lead to bedding and pooling, leading to underwhelming espresso shots.
The form and posture we suggest might seem like overkill: but it's designed to protect you. Good form doesn't just help you apply even, consistent pressure. It relieves the strain on your wrists - the baristas (ahem) Achilles heel. RSI's are common among barista's, and bad tamping form is the culprit.
Dose your coffee and add to the filter basket. You'll probably know how much you like to dose, but anywhere between 6-8gs of coffee is standard. If you're dosing straight from the grinder, you'll now have a portafilter piled up with loose coffee grounds.
Tap (if you want)
To tap or not to tap - that is the question. Some baristas will tap the portafilter to distribute the coffee grounds at this point; though other baristas think that tapping can create weak points in the puck and lead to channelling. We'll let you decide, but would posit that with a decent dosing grinder, the distribution should already be pretty even.
Distribute And Even The Grounds
If you want to ensure totally even distribution, you can employ a distribution tool or stirring tamp to mix up and/or even out the coffee grounds. Or, just level off your coffee with your index finger and brush away any excess grounds around the rim.
Place the portafilter on your mat, on an even surface. A level surface is crucial, so that you can achieve a flat puck. The mat will provide cushioning, prevent slipping, and help you tidy up when you're done.
Before we tamp, it's time to assume the position. Good tamping form not only helps you to deliver force evenly into the puck, but it protects your wrists from injury too. Stand with your tamping hip (the side of your dominant arm, normally) adjacent to the counter.
Now, you should have your arm bent at 90 degrees, with your upper arm alongside your body, and your wrist straight above the portafilter. In this position, we can tamp easily without applying force via the wrist, using the body instead.
It's time to tamp. For the first tamp, you don't want to press too hard. What's important is applying the same pressure across the puck, so all the grounds are compacted evenly.
Hold your portafilter level on the mat. Hold the tamper as if you were shaking hands with a doorknob, and apply light, even pressure to the puck. If you're unsure how to gauge the force you're applying, skip to the end of this article. For the first tamp, you want to apply around 15lbs of pressure. But don't obsess on the force - the most important thing is to apply pressure evenly.
Now, tamp again, but this time with a little more force. You should aim for anywhere between 20-30 lbs of pressure on the second push. Hold for a few seconds, and as you release slightly, slowly turn the tamper in a twisting motion as you release the pressure.
This will help keep the density even, and flatten the top of the puck - which is why it's often referred to as polishing the puck.
Have a look at your puck - does it look flat, and consistent? Any signs of cracks or pinholes will lead to channelling, so it's best to identify and fix issues now. If it all looks good, clean any loose grounds away from the edges of the portafilter with your index finger, and you're ready to go!
How Do I Know How Much Tamping Pressure I'm Applying?In our everyday lives, we don't often think in lbs as we apply pressure. So being told to apply 15lbs of pressure doesn't mean much to many. Don't obsess too much with getting the exact pressure we've stated above.
Getting close, and being consistent are more important. One classic barista training trick is to practise tamping on your bathroom scale to gauge the pressure. This might seem odd, but once you've learned how to recognise pressure by feel, it will become second nature.
Another option is buy a calibrated tamper, which will display the tamping pressure you're applying to the bed of coffee. As brewing espresso is such a precise art, even professional baristas nowadays are ok with using this little cheat tool.
With all of the complexity and expense around brewing espresso at home, there's no excuse to throw it all away with a bad tamping technique. Follow these stages and you should be tamping perfectly, every time, in no time at all.