Coffee Data Science

Wafo vs VST: Espresso Filter Basket Analysis

Looking towards the future of espresso baskets

Robert McKeon Aloe
Nerd For Tech

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Wafo is bringing a new espresso basket to market, along with a few others, that bucks the stable line of precision baskets for the past decade. I got one a little earlier through a friend of a friend. I initially got the Wafo Classic, and I bought a SOE/Spirit that I will have some data for soon.

All images by author

For now, I used hole analysis to look at the top and bottom of the basket holes. To do this, I imaged the filters from the top and the bottom, and then I used Procreate to align them. This also corrected for the height offset due to measuring the bottom of the basket where the basket is upside down on the screen.

Manual image alignment

Afterwards, I examined each hole and had the measurement between the top and bottom aligned.

Wafo Classic Filter Basket

I looked at the hole sizes, and there were some variations, but it was pretty expected compared to previous filters.

Holes colored by size. Yellow is larger, then the color transitions to dark blue.

The hole distribution between the top and bottom had a shift as well.

We can also visualize this ratio on the filter holes. A ratio of 1:1 means the hole is the same diameter for the top and bottom. This shows some variations with some holes is larger than others.

We can plot these holes for the top vs the bottom, and this shows an interesting distribution.

VST Filter Basket to Compare

Of course, this data doesn’t mean much in a vacuum, so I did the same analysis on a VST filter basket.

The hole distribution showed something I hadn’t seen before. From the top, the holes are tightly packed around one peak, but from the bottom, the distribution is much more spread out. The VST had a long tail, and I’m not sure how much photography errors play into this spread.

Measuring the ratio between top and bottom is a lot tighter of a spatial distribution than Wafo.

In a scatter plot, one can see many of the holes measured from the top have a wide distribution of the bottom hole measurement.

Wafo Classic vs VST

Overlaying the Top/Bottom ratio vs Bottom Hole Diameter, the VST has a similar spread as Wafo.

The Wafo has a larger overall opening, but the hole diameters appear to be about the same in average and standard deviation.

This analysis really points to more that could be understood about precision baskets. We measure precision in one spot, but really, precision is required from the top and bottom of the filter holes because this will ultimately determine flow. I’m curious how changing the size difference affects flow, and I’m looking forward to the Wafo SOE/Spirit.

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Further readings of mine:

My Book

My Links

Collection of Espresso Articles

A Collection of Work and School Stories

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Robert McKeon Aloe
Nerd For Tech

I’m in love with my Wife, my Kids, Espresso, Data Science, tomatoes, cooking, engineering, talking, family, Paris, and Italy, not necessarily in that order.