I thought I’d provide some thoughts on what may be the most under appreciated piece of coffee equipment in the espresso making arsenal, the portafilter (“PF”) basket. Coffee beans are ground in order to increase the surface area to volume ratio of the coffee and aid in extraction of flavour and soluble elements. The PF basket provides a convenient place to hold the ground coffee whilst hot water is passed through it at pressure. There are two further attributes which I would ask you to think about each time you pop your PF basket into your PF handle. The basket necessarily provides some level of flow restriction and the basket will hopefully be very consistent in terms of its manufacturing quality.
You’ll generally be aware that espresso making recipes generally describe a window of time during which the machine is pumping pressurised water through the coffee puck which will produce a certain volume or weight of espresso. The time of extraction and amount of espresso produced describe a set of parameters whereby the coffee will not be under extracted (too acidic and lacking in body) or over extracted (exceedingly bitter or burnt tasting). The relationship between the fineness of grind of the coffee and the flow restriction characteristics of the PF basket is important in determining how fine you grind your coffee in order to generate a well extracted cup of coffee. My contention would be that a PF basket demonstrating minimal flow restriction is ideal. This allows you to grind your coffee finer and extract the most out of your coffee without over extracting it.
You’ll also be aware that in preparing your ground coffee puck that you don’t want to see “channelling” when you turn the pump on. Channelling occurs when the coffee puck is not uniform and there are pathways that the pressurised water takes preferentially in passing through the puck simply because the resistance to flow in those pathways is lower than average. You end up with a cup of coffee which hasn’t extracted flavour and texture optimally. The same could be said for a poorly manufactured PF basket. If there is unevenness in the set of filtration holes then that is tantamount to having a poorly prepared coffee puck every time you step up to your machine. I think it’s very helpful using a PF basket which is fundamentally well made. There are plenty available from companies such as VST, IMS, Pesado, Decent. I personally use VST baskets (unfortunately I have no relationship with the company other than being a happy customer).
So if you’re the type of person who thinks about upgrading your stuff… one of the most effective and cost efficient ways of levelling up your home espresso experience might well be to invest in a new PF basket!