In the (now) far 2014 we decided to provide technical foundation to the development of our tamper bases. Being amongst the first ones to produce these bases with concentric grooves and having heard frequently the fateful question “but what’s the difference?” we decided to explore and study to the bottom the small hints that these tampers actually produce. We chose to rely on a professional as Benjamin Graf (Austrian Latte Art Champion for three years in a row, certified SCA trainer and trainer at Mumac Academy) and together we have fully investigated this topic carrying out proper comparison tests and analysing all the variations in each case.
To carry out the test every Asso Coffee branded base has been made available, all over we have brought out 6 different types of tamper bases:
- 58mm Flat
- 58mm Convex
- 58mm Concentric Strong
- 58mm Concentric Soft
- 58mm Concentric Light
- 58mm Concentric Deep
Coffee machine used for the test: La Cimbali M100
- Water temperature: 93°C
- Water pressure during the brewing step: 9 atm
- Filling quantity: 25 ml of water
- Portafiler diameter (therefore tamper diameter): 58mm
The test started with the making of a regular coffee (the baseline coffee to which we made the various comparisons) using the tamper with a FLAT base. The result has been then tasted and evaluated by Benjamin.
The analysis of the results has been performed observing the following parameters:
- Time of extraction
- Consistency in extraction
These are the fixed parameters for the analysis of an espresso.
FLAT base tamper
The base is perfectly flat, without any convex or concave part. Probably the most used tamper ever. This has been used to create the “reference coffee”.
CONVEX base tamper
The difference between Flat and Convex is clearly recognizable from the taste. The extraction time is the same but the coffe prepared with the Convex tamper has more fullness and more body. The Convex tamper is useful in the majority of the cases to avoid the channeling effect.
STRONG base tamper
The extraction time is steady and unchanged but the differences in taste vary depending on the roasting: for the darker roasting a slight increase in acidity can be noted.
SOFT base tamper
The time of extraction is the same. The taste of the coffee prepared with the Soft base didn’t show any difference with regards to the Convex base.
LIGHT base tamper
The time of extraction was higher of 2/3 seconds compared to the standard of 25 seconds. An extraction that takes longer probably results in the development of a more compact cream. The coffee tamped with the Light base showed more body than the one pressed with the Strong base and a sweeter taste than the coffee tamped with the Convex base.
DEEP base tamper
The very deep grooves of the DEEP base showed great results on different types of blend:
- Increase in acidity and body on lighter roastings
- Increase in acidity on Robusta coffee blend with a positive effect, because it softens the typical intense flavour of robusta
“My opinion is that, since there are big differences among the various types of roastings and blends, it is not possible to classify one of the tampers as “The Tamper”: for each type of blend and roasting level there are several possibilities to improve the extraction.
The test carried out revealed how the consistency in extraction is way better using a tamper with a carved base instead of a base without grooves: the groove as a matter of facts allows you to give water a direction in the flow which makes the extraction more consistent.
The arabic blends seem to react very well with the bases with thin lines, while the robusta blends seem to benefit from thicker lines”.
Sca Trainer, Mumac Academy Trainer
Austrian Latte Art Champion 2015, 2016, 2017