All About Portafilters
We've talked plenty about the differences between baskets in the past. This means you probably already know that a pressurized basket helps mitigate grind quality in espresso brewing. One thing that can be far more noticeable on first glance though is portafilter type! It's not always clear what a "standard" portafilter is, what about sizing? Materials? Spouts?
But we're here to help. Read on for some portafilter basics that'll put you in the know.
Spouts are one of the most notable features of a portafilter. The spouts on a portafilter are designed to direct the flow of coffee into your container. Single spout portafilters are generally used when brewing for one, whereas with a double spout you can brew into two glasses at once. But that's not all that having a double spouted filter can help with. One of the keys to ensuring even extraction with espresso is producing an even tamp. Keeping the grounds level in your portafilter is important, as then water flows through the puck evenly as well. A double spouted portafilter can help you identify an even tamp. If you brew into two shot glasses from a double spouted filter and they contain equal amounts, voila! You know you've achieved an even tamp. For even more accuracy, enter the bottomless portafilter.
You've probably seen gorgeous shots of perfectly colored espresso pulling directly from the portafiler's screen. This is possible with the use of a bottomless portafilter. These filters remove the spouts, and metal bottom entirely. Instead, without a basket inserted these portafilters look like a ring. Using a bottomless portafilter can help you see exactly where your tamp may be uneven. If the espresso meets in the middle into a single stream, you know you have that perfect tamp. Plus, it looks pretty!
Material is a factor in portafilter design, but may not be as imperative as you think. The biggest and most important thing imparted by material is durability. A good portafilter should last you years, so whether its all stainless or chrome-plated brass, a durable metal is important. Some lower end machines may come with plastic lined filters that could chip and wear over time. Stainless, on the other hand, won't nick or scratch easily. Chrome-plated brass tends to fall somewhere in the middle, offering longevity and strength but at a greater risk of scuffing than stainless. Material can also impact ergonomics, as heavier metals might cause more strain if you're constantly operating the machine.
There's also the importance of heat conduction. If the bottom of your filter is less warm than the top, it means the water passing through it could lose temp as it passes through the grounds. This is a granular detail, but hobbyists will want to control for every variable. For E61 groupheads, which actively heat the portafilter, this means that a stainless steel filter will stay hot as long as the machine is on. With that in mind, for machines that rely on water flow to heat the portafilter, chrome-plated brass is a more heat conducive material.
Size and Ergonomics
There isn't a huge difference between portafilter sizes. It's true that 58mm filters tend to have slightly more even pressure distribution through the puck. This is because a thinner, taller filter will see a greater pressure difference from the top of the puck to the bottom. However, this is such a granular detail that it has little bearing on actual brewing. Instead, size has more to do with ergonomics and part availability. It's much easier to find 58mm portafilters of different materials and styles that are interchangeable than with 54mms. Since 58mm filters are generally "industry standard" in commercial coffee, you can usually find them after-market. This means you'll be able to find options with different spouts, materials, and handles.
You'll also be able to utilize a wider range of accessories and grinders easily with a 58mm filter. Most espresso grinders with portafilter hooks are generally designed with 58mm in mind, and will offer a better fit.
All of this, of course, its a moot point without a stand out machine. While it's fun to drill into the specifics of portafilter design, the most important parts of your coffee set up will always be machine and grinder!