Portafilter baskets are a sadly neglected item in the espresso arsenal, which is a shame because their performance is one of the large contributing factors to the taste and ability to replicate great espresso. Most espresso machine companies have treated filter baskets as an after-thought by delegating basket production to outside manufacturers. A couple of weeks ago Vince Fedele of VST released a new basket design that serves as an example of a company researching and developing a filter basket that aims to correct some of the mistakes produced by other filter basket manufacturers. Here’s how:
VST is able to measure the size and quality of the holes that allow espresso to extract from the bottom of the bed of espresso. The size and shape of the holes is very important because they dictate what types of particles are being allowed to pass through the filter (I liken it to a membrane in a cell). VST was able to find an optimal spread of 5 different sized holes that allow flavor solids to pass through the filter basket while minimizing the amount of non- dissolved solids that pass through the filter. Non- dissolved solids are 70% cellulose by weight and add a vegetative taste to the final product so it stands to reason why it is important to minimize their presence. Current baskets tend to allow 9-13% of the non-dissolved solids through the filter, while the VST baskets allow only 4-6%. Each basket even comes labeled with a digital readout of the quality tests performed after production.
There is a significant improvement in the shape of the basket as well. For the last few years I have needed to measure baskets in order to find a set that is similar to allow consistent dosing among different groups on the espresso machine. The VST baskets are consistent sizes and volumes, which allows a coffee professional the luxury of being able to dose using leveling tools granted that their distribution of the espresso into the basket is consistent as well. Being able to recreate the weight of dry coffee that is being dosed into the portafilter is important because it allows the barista to replicate results and adjust their grind to produce a consistent volume of liquid espresso. In combination with a refractometer that measures extraction levels of liquid coffee, the ability to dose and distribute dry coffee in a replicable way is the next step in making espresso coffee into a formula rather than leaving factors to chance.
The current trend in baskets has been to buy laser cut. Sounds good, right? What Fedele has learned through testing is that laser-cut holes offer no particular advantage to holes that are machined properly and that the laser-cut process is detrimental to the structural integrity of the basket. I’ve experienced this when the side- wall of the laser cut baskets that I used to use would pull away and crack. VST’s machining process ensures that holes will be properly drilled and de-burred without weakening the structural integrity of the surrounding material on the rest of the basket. The baskets are further reinforced because they are made of a superior material (I’m assuming a higher grade of stainless steel than the traditional 304 food grade). When I weighed out the VST baskets in comparison to my old baskets there was a full 5 gram difference between the two.
After using the baskets for about a week I’m sold on the quality and precision with which they are made. This can only mean good things for the future of basket production because it forces others to step their game up. For being such an integral part of the espresso brewing process the filter basket has been highly undervalued and I’m glad that that some focus has shifted towards proper production of an item that has such an effect on taste.
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Hi Colter,
It makes sense that a consistent cup of quality coffee requires precise control over the factors that affect flavor, and it’s probably possible to use those precise tools to experiment with the much less precise crops of coffee beans. Coffee is thus an open collaboration between precise and loose control.
Our tools are precise but our material is not. We’ve the minute control of the espresso and the roasting machine, for instance. Obversely, we’ve the capriciousness of nature in his / her crops beans. Coffee roasters needs to make the most out of whatever nature provides. It’s more like parenting than like pottery, and it’s more like basketball than like archery.
As a computer programmer who thrives in closed situations, it would be a challenge for me each time a new coffee crop arrived. My bliss would be controlling the precise tools, and my challenge the dynamics of coffee beans. The ambiguity of whether my final results tastes “good” would have me longing for clear finish lines.