Coffee Data Science
CoffeeJack and Wafo vs VST, Flair and Kompresso Espresso Filter Basket
Imaging analysis of filter baskets
I started looking at filter baskets a few years ago, and I looked at how random extremely large or small holes were spatially arranged. I wanted to understand if that could be used to help explain why some baskets performed better than others.
So when I got a CoffeeJack, I took the same approach. I compared it to Kompresso because Kompresso has been by defacto travel machine for three years. I have been surprised that for the same grind, water, and pre-infusion, CoffeeJack outperforms Kompresso in taste and extraction (results in another discussion). I think it has more to do with the filter basket than other factors because Kompresso is the least complicated portable espresso machine. It is the equivalent of a portable lever machine while CoffeeJack is a pump.
So, I collected some data. I also collected images on Flair Signature because it is my other travel machine as well as a VST basket. The fun wild card was the Wafo basket, which they sent me a good image to do this analysis.
In full disclosure, Ashley at CoffeeJack sent me a unit because he wanted technical feedback. So we have talked, but he won’t see this article before it goes out. One of my criticisms was well received which was the coffee bean logo in the center. That logo modifies flow both from the shower screen and the filter basket. His response was simply they liked the way it looked, but it doesn’t mean it won’t change in future iterations.
Data
Let’s start with hole count and the percent of the filter open. CoffeeJack has double the number of holes as the competitors. Wafo is in a different league, and I think it steals the show from what I’m trying to discuss in CoffeeJack. In terms of the percent of the filter open, Flair, CoffeeJack, and Wafo are the best.
But wait, maybe not. For the Flair, the holes don’t go all the way to the edge. If you also consider the edge in the calculation (increasing the filter area by a factor of 1.8), Flair has the same percentage of the filter open as a VST as seen below:
Wafo is still a few months off from mass distribution, and CoffeeJack seems to have the largest opening of currently available baskets. In talking with Ashley, the team iterated through the design based on keeping a back pressure for the pump to maintain flow rate. They weren’t aiming to come out with one of the most open filter baskets on the market. A happy accident?
In terms of hole diameter, CoffeeJack is in line with VST, Kompresso, and Flair with respect to hole diameter average and standard deviation. CoffeeJack holes are slightly smaller, but there are more. Wafo has wildly larger holes, but my algorithm was trying to calculate assuming circular holes, and Wafo has rectangles so I’m not sure the impact.
We can look at the hole distribution, and CoffeeJack is shifted as is Kompresso from VST and Flair.
Spatial Distribution
These images show relative hole sizes. So more yellow means a larger hole, and darker blue means a smaller hole. The hope is that these hole sizes will not fall into a pattern. Unfortunately, they do, and this pattern is seen during extraction. I have been able to tell the difference between my two Flair Signature baskets based on how the coffee flows and their hole patterns. Even VST doesn’t have this ideal distribution while being better than previous baskets.
Kompresso and CoffeeJack have their own. However, CoffeeJack isn’t bottomless, so I can’t tell how much this pattern plays out. In Coffee Jack’s case, there could have been a slight off angle with the camera as seen by larger holes being up top and smaller holes being on the bottom. Kompresso hot spots are evident during the shot.
From the bottom of the spent puck from CoffeeJack, I haven’t seen a particular pattern that would indicate a very low flow caused by the dark blue area aside from in the center due to the logo.
Wafo is just fun! This could have a similar angle issue in the camera. I didn’t take the image, so I’m only showing what I have. I’m very excited for their filter basket.
CoffeeJack happens to be on the wave of the future of espresso baskets. My criticism of precision baskets a few years ago is the same as now: they are not precise enough in their distribution across the screen as there are hot and cold spots.
I hope more research is done into filter baskets with more holes because I suspect they will allow a finer grind, and I believe this to be a key for higher extraction and better coffee.
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