Staccato Tamping: Improving Espresso without a Sifter

Introducing Split Tamping for Improved Espresso

Most of my coffee experiments are done casually throughout the day. Because of the shelter in place orders, I moved my coffee bar to my house, and I’ve had a fair amount of lattes and non-staccato espresso shots. Regular espresso shots are mainly desirable to me for the time aspect (much quicker than staccato shots) which jives well with espresso drinks. Half my shots at home have been regular shots, and I stumbled across staccato tamping out of convenience.

The technique is not new, but how it functions has been unknown until now. Simply put, staccato tamping is filling the basket halfway, tamping, filling the rest, and tamping again. The difference between previous work and this work is the understanding of why it makes a better shot and the special trick in the two tamps derived from the theory. Staccato tamping is not split tamping (dose half, tamp X lbs, dose second half, tamp X lbs where X is defined by the barista). Staccato tamping is dose half, tamp X lbs, dose second half, tamp Y lbs where Y is much less than X.

In this article, I describe the previous work, the staccato tamping theory and methodology, and some numerical results where I explore for a better understanding of how the method functions. The beauty is that anyone with an espresso machine can attempt this technique at home as long as they have a tamper and a steady hand.

Previous Work

A forum in 2003 had a short discussion on the split tamp technique, where there was much skepticism except for one or two who used something similar. They called it double tamp or double dose or split tamp.

In 2005, someone started a discussion on tamping at the halfway mark. They didn’t know why it made an improvement, but they noticed something.

In 2009, a barista was seen tamping the first half and then the second half with a 30 lbs tamp. They had been doing this for some time.

In 2015, there was a short discussion on Reddit about double tamping but no explanation or claim that it was better.

In 2017, another person ran across something similar, but like the previous threads, there wasn’t a theory on how this technique functioned. They asked if there was a name. Potentially, double tamp would be a good name, but based on how it improves the shot, staccato tamping is more applicable.

All of these examples are clear in that they don’t do a range of experiments to examine coffee extraction nor does anyone really understand what physically would allow a split tamp to succeed.

A Discovery by Convenience

I have been using roasted beans from Hawai’i, and they were a dark medium roast. As a result, they take up more volume when ground, and I wasn’t used to using only 18g in my 20g basket when I typically use 22g. It could get messy, so I started split tamping (dose, tamp, dose, leveler).

Around the same time, I had been working on doing visual analysis for why I kept seeing donut extractions even with Staccato espresso shots. They don’t have the same kind of channeling issues because each layer has a more even particle distribution.

My typical staccato shot is 8g fine (<400um) on the bottom, 8g coarse (>500um), 6g mid (between 400um and 500um) on top. From simulations, channelling is always occurring in a normal distribution of particles, but by splitting layers, the channeling affect is reduced causing better extraction.

In my donut analysis, I thought the donut shape was caused by the fine layer, but I discovered the mid layer on top of the puck had the biggest impact. If all the fine particles aren’t sifted out or the tamp is too hard, I get a lot of channeling. The theory was that channeling doesn’t exist much in the coarse particles as they can’t be compressed much through tamping. The fine particles can be compressed, but when the water hits them, they fuse together causing it to behave differently. The evidence to support this theory is that the fine layer is on the bottom but doesn’t clog the filter holes as one would think. The mid layer, however, can be compressed more than the coarse and appears to be highly sensitive.

To better understand this variable, I started tracking in my data sheet how far down the leveler was going instead of using something like the force applied to the tamper. I found the lightest pressure worked the best, and dialing in a grinder turned into literally dialing my leveler up or down.

Staccato Tamping

Staccato tamping was the result of applying knowledge from the staccato shot to a regular shot. The layering in a staccato shot is ultimately layers of coffee densities as a result of the particle sizes. So, if you have two layers of different coffee densities, the result could be modified to come out similar to a staccato espresso shot. In staccato tamping, the bottom layer had a higher density than the top which simulates sifting the grounds and having a shot with a fine layer on bottom.

This setup was derived from some experimentation where I was mainly focused on getting a good extraction and a high Total Dissolved Solids (TDS). I was using these test shots in espresso drinks, not straight shots. Then I tried a few espresso shots using this tamping technique, and the results were definitely better.