For the longest time, tamping has been one of the few manual tasks that a Barista performs when preparing espresso. Naturally this means it comes with a lot of personal opinions about how to do it best. In more recent times the introduction of automatic tamping machines has brought considerable controversy into the Barista world. Is there a component of tamping that a Barista can execute more proficiently than a machine? This is one coffee debate that can be swiftly brought to rest.
As I’ve mentioned in previous articles, people are exceptional at tasks that require finesse, emotion, and reasoning. There is absolutely no part of the tamping process that requires these skills.
Tamping is the act of compressing the fluffy coffee grounds into a tight puck. Coffee grounds are really strong, and don’t actually compress when you tamp them. Instead it’s the air between the grinds that you’re squeezing out. No matter how hard you press, you can never squeeze all the air out. At a certain - surprisingly low - pressure the grinds are all squished together and will not move any further without a hydraulic press. This means that there are two possible end states after tamping:
1. the grounds are as compressed as they could be.
2. the grinds are somewhere between completely un-tamped and 1.
With 2. you’re never sure how much air is left. This means it’s a variable; something that will introduce inconsistency into your coffee making. Coffee making is almost entirely an act of understanding and controlling, or removing, variables. If I have the option of eliminating something as a variable, then I will jump at the opportunity.
When tamping manually, you never know if you’re sitting at 1. or 2. Nobody's wrist has a pressure transducer in it. Nor are they indestructible; the act of repetitively tamping grounds hundreds of times a day could be seriously debilitating in later life.
In my humble human opinion, tamping is a task at which machines are exceptionally suited, and one which my body is more than happy to surrender!