Coffee Data Science
Finer Coffee vs Wafo Spirit: Espresso Basket Comparison
Unifilter with a curve?
The Finer Coffee filter basket and portafilter gives similar vibes as the Weber Unifilter in that it has a nice weight, nice ascetics, and precision holes. However, unlike any filter basket in production, the Finer basket has a curved bottom. There have been other filter baskets with a curved bottom but inside of the basket was also curved. In the case of the Finer Coffee basket, the inside of the basket is flat.
The owner asked if I would like to try out the basket and compare. This does present some bias, but I will still give my feedback both qualitatively and quantitatively compared to the Wafo Spirit basket, which I think is currently the best espresso basket.
The inspiration behind the curved bottom was a frustration with high precision baskets not forming one stream of coffee like a tradition espresso basket.
The design was nice, but I had two critiques:
- In my slow flow style of shot, some of the streams from the holes would hit the side lip and run down the handle.
- The basket was part of the portafilter.
For the coffee hitting the lip, that could be fixed by removing the lip. I was reminded of the Flair Signature.
I suggested offering a stand-alone basket because many have plenty of portafilters. This would be more cost conscious for most home baristas.
Tasting Equipment/Technique
Espresso Machine: Decent Espresso Machine, Thermal Pre-infusion
Coffee: Home Roasted Coffee, medium (First Crack + 1 Minute)
Pre-infusion: Long, ~25 seconds, 30 second ramp bloom, 0.5 ml/s flow during infusion
Filter Basket: 20 Wafo Spirit
Other Equipment: Acaia Pyxis Scale, DiFluid R2 TDS Meter
Metrics of Performance
I used two sets of metrics for evaluating the differences between techniques: 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.
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, called Extraction Yield (EY).
Data
I collected data over 24 shot pairs across multiple roasts. I didn’t find a statistical difference between the performance of the two baskets.
Taste has movement both ways, but no pattern.
I thought dose might be an issue because the Finer Coffee basket seemed similar to the Unifilter in requiring a 1g higher input dose. However, I didn’t find conclusive data that increasing the dose gave better performance.
The average individual component scores were almost the same. Sour and Bitter seemed slightly offset, so it is quite possible the basket is better for bringing out sour notes and minimizing bitter ones. The higher the number, the better. For Sour and Bitter, a higher number means less sourness or less bitterness.
In terms of TDS/EY, there was no statistical difference, but there was a lot of variation.
In term of statistical differences, a two tailed paired t-test did not show any statistical significance except for the Sour component of taste. I wonder if longer ratios or different shot profiles would show taste improvement.
I shared some criticisms of the Finer Coffee basket and some data where I didn’t find a difference in performance between this basket and the Wafo Spirit basket. There was a difference for the sour note, but overall it was a good experience.
The last point of potential contention is the price, which is why I think a standalone basket would be better for most home espresso people.
If you like, follow me on Twitter, YouTube, and Instagram where I post videos of espresso shots on different machines and espresso related stuff. You can also find me on LinkedIn. You can also follow me on Medium and Subscribe.
Further readings of mine:
My Second Book: Advanced Espresso
My First Book: Engineering Better Espresso
