So you have a portafilter, you have ground coffee, and you’re ready to tamp.
Coffee tamping is not an exact science, but it is a skill that can be learned through practice.
You’ll be pleased to know that tamping espresso grounds correctly isn’t as complex as it may seem.
Read on as we break down everything you need to know about tamping.
What is espresso tamping?
Tamping is the process by which you compress the coffee in your portafilter basket, causing it to become more compact.
Tamping creates resistance for the water flow that agitates the coffee and helps release flavour oils and other solubles.
Put simply, if you leave the espresso grounds loose in the basket, the air gaps between the grounds will be too large and water will flow through the grounds too easily. By compacting the grounds, we reduce the size of these air gaps.
It is a crucial step in the espresso-making process and yields a significant effect on cup quality.
The tamping process is conducted using a coffee tamper. This is a small cylindrical device with a handle on one end and a flat, circular base on the other.
The base is placed over the grounds, and then downward pressure is applied to the handle.
Why is tamping important?
Tamping the ground coffee into the portafilter basket gives it a higher density and therefore makes the water work harder for extraction. In order to extract the best taste, you should learn the proper way to tamp.
If you don’t compress the grinds sufficiently, water will flow through them too quickly and the brew will be weak and taste sour. You may end up with a weak, watery beverage that lacks body and flavour.
If you over-tamp, then the water will have trouble flowing through your puck and it will take longer to pull a shot. This can often lead to over-extraction and bitter flavours.
Effective tamping will also help you avoid channelling.
Channelling is what happens when water flows too quickly through one part of the coffee puck instead of evenly throughout. Channelling can occur if you tamp too lightly or if you don’t tamp your coffee evenly.
If you notice that your espresso machine is producing liquid only on one side of the portafilter, or if some parts of the puck look light and others are very dark, your shot is probably channelling.
How to tamp your espresso the right way
First, make sure that the portafilter is empty and clean.
Using a scale, measure out 22 grams of freshly ground coffee into a double portafilter basket.
Ensure the coffee grounds are evenly distributed. There is a range of methods available for this (see coffee distribution section later on).
Position the tamper firmly against the grounds at a 90-degree angle and then press down using about 30 pounds (13.6kg) of pressure for about 10 seconds (you can use a bathroom scale to weigh the force).
If needed, wipe away any excess grounds from around the edge of the portafilter basket with a damp cloth. Pull your espresso shot.
If you find that your shots are coming out too quickly, try tamping harder over time until you reach a good balance between flow rate and flavour intensity.
How hard should you tamp your coffee?
There are many important variables involved in preparing espresso. Among them are:
- grind fineness and consistency
- dose/weight of coffee used
- tamping pressure
If you’re a novice barista, it’s important to know that the pressure you use to tamp down the ground coffee into the portafilter basket will have an impact on the resulting espresso.
A light tamp may result in an espresso that tastes weak and watery due to the inconsistent density of the coffee grounds.
On the other hand, it has long been thought that if you tamp too hard, your shot may taste bitter and unpleasant. However, current thinking is that it’s hard to do much damage from tamping too hard (more on this below).
What is “the right amount” of tamping? It all depends on how finely ground your coffee is, but for most home espresso machines with entry-level grinders, 30 lbs (13.6kg) of pressure should be about right.
It’s best to practice until you feel comfortable with this amount of pressure.
If you’re having trouble with your shots, try varying your tamping technique slightly until you get an espresso that tastes perfect to you!
Don’t overthink tamping pressure
More and more experts in the coffee world are now of the view that tamp pressure plays a smaller role than previously thought.
In fact, once tamp pressure is above a certain level, incremental changes in pressure have a very minor impact on the density of the coffee grounds, and therefore the resulting espresso shot.
This is because once grounds are compressed to the maximum level of compactness, it’s hard to compress them any further with manual tamping. And, the good news, is this “maximum” level won’t do any damage to your coffee.
So, in short, tamp as hard as you can comfortably do so but don’t worry too much about the exact pressure measurement.
This school of thought is also related to the movement of paying closer attention to the physical wellbeing of baristas. In particular, many suffer from repetitive strain injuries (RSI) as a result of tamping.
How important is it being level?
It’s essential that your bed of coffee grounds is perfectly flat. Remember, water takes the path of least resistance, so if one area is lower than another, water won’t flow through your coffee grounds evenly.
Ensure you are using a flat tamper (not curved) and that the bed of coffee appears completely flat visually.
Coffee is usually ground directly into the portafilter. As you may have observed, it very rarely has an even distribution, with a larger mound of grounds usually on one side or another of the filter basket.
This is something that needs to be addressed before we tamp, because if we tamp unevenly distributed grounds, the resulting coffee bed will also be uneven and will likely lead to uneven extraction.
For more home baristas, there’s no need to overthink this process. The goal is to simply make sure the grounds appear evenly distributed before you tamp.
For most people, using the palm of the hand to tap the side of the portafilter is the best method.
Other options include:
- A coffee distributor tool
- Tapping the portafilter on the bench
- Using your fingers to manually redistribute