Espresso Baskets (VST): Ridged vs Ridgeless
A small study to search for a performance difference
There has been an assumption in the world of espresso that there is no performance difference between ridged and ridgeless baskets. I wanted to examine this claim just in case it was a bad assumption because I haven’t seen any data on it. So I bought a ridgeless VST basket to compare to my ridged basket.
Long story short: I didn’t find a performance difference in taste or extraction across multiples roasts and shots, but the caveat is that I had only one basket sample of each type.
I did an initial simulation below about water flow. It was a bit extreme, but I felt it justified the look. A notch caused such a wild change to the flow of the shot, and in reality, it probably didn’t have that big of an effect, but I wasn’t sure. To me, I’m trying to isolate problem sources so I can fix them.
I started alternating filters, and I wanted to get to a dataset that would be statistically meaningful if there was a difference. However, there was not in difference.
Metrics of Performance
I used two metrics for evaluating the differences between filters: Final Score and Coffee Extraction.
Final score is the average of a scorecard of 7 metrics (Sharp, Rich, Syrup, Sweet, Sour, Bitter, and Aftertaste). These scores were subjective, of course, but they were calibrated to my tastes and helped me improve my shots. There is some variation in the scores. My aim was to be consistent for each metric, but some times the granularity was difficult and affected the final score.
Total Dissolved Solids (TDS) is measured using a refractometer, and this number combined with the output weight of the shot and the input weight of the coffee is used to determine the percentage of coffee extracted into the cup.
Data
All my data was paired so each pair had the same parameters. By doing the testing this way, I was able to continue other experiments. I usually stopped the shot at a 1:1 output to input ratio, and I collected the liquid past this point in a separate cup (allowing me to measure the 3:1 extraction). Below shows the paired comparison. Some times the ridged filterdf is better than ridgeless, but some times it isn’t.
If we separate out staccato shots and non-staccato shots, there still is not a trend.
We can even sort all the shots by Final Score or Extraction yield, and it doesn’t look like there is much of a pattern, particularly in taste.
I dove a bit deeper to look at the dependences on ratio vs output, and I still didn’t see any pattern to suggest they were different.
I am aware this is information overload. However, I want to provide some confidence that at least for two specific ridged and ridgeless filters, there is not a measurable performance between the two.
If you like, follow me on Twitter and YouTube where I post videos of espresso shots on different machines and espresso related stuff. You can also find me on LinkedIn.
Further readings of mine:
To Stir or To Swirl: Better Espresso Experience
Spicy Espresso: Grind Hot, Tamp Cold for Better Coffee
Staccato Espresso: Leveling Up Espresso
Improving Espresso with Paper Filters
Coffee Solubility in Espresso: An Initial Study
Staccato Tamping: Improving Espresso without a Sifter
Espresso Simulation: First Steps in Computer Models
Pressure Pulsing for Better Espresso
