I want to take a second to talk about pressure. For my barista friends, no I don't mean the pressure you feel when you have a line out the door and the mother of three is standing at the counter watching you make someone else's drink. We're diving into the world of variable pressure espresso machines, where baristas play conductor to a symphony of bars and atmospheres that would make your high school physics teacher proud.

Picture this: You're standing in front of your shiny espresso machine, armed with the knowledge that 9 bars of pressure has been the industry standard since someone decided that was the magic number. But here's the thing – what if I told you that coffee, like your most complicated friend, doesn't actually want to be treated the same way all the time? 

The Thick of It: Pressure and Viscosity

Here's where things get interesting (and a bit thick, literally). When you start playing around with pressure, dropping it below that standard 9 bars while keeping your typical 2:1 ratio, something magical happens. Your espresso starts getting thicker than your cousin's conspiracy theories. It's like your coffee decided to hit the gym and bulk up, developing a viscosity that would make honey jealous.

Now, if you're thinking, "Hey, isn't that just a ristretto shot?" – you're not entirely wrong. Ristretto shots are indeed known for their syrupy thickness, but they often come with enough acidity to make a lemon pucker. It's like getting a massage from someone who's angry at you – sure, you're getting what you asked for, but at what cost?



The Smooth Operator: Enter Pressure Profiling

This is where pressure profiling struts in, wearing a leather jacket and looking cooler than a frozen portafilter. It's basically the jazz of the espresso world – taking the best parts of traditional methods and adding room for improvisation.

Think back to those classic lever machines from the '40s and '50s, when baristas had to manually pull their shots like they were doing bicep curls. These machines accidentally stumbled upon something brilliant: varying pressure throughout the extraction creates complexity in flavor that a flat 9 bars could only dream of achieving.

Modern pressure profiling is like sending your grandfather's wisdom to coding bootcamp – it takes those time-tested principles of lever machines and adds precision that would make a Swiss watchmaker weep. With today's machines, you can program pressure curves that start gentle, ramp up for the main extraction, and ease off at the end, like a perfectly choreographed dance routine.

The result? You get that luxurious thickness without the face-scrunching acidity. It's like having your cake and eating it too, except the cake is coffee and it's technically a beverage but you get what I mean.

The beauty of pressure profiling lies in its flexibility. Want to start with a gentle pre-infusion that makes your coffee bed as comfortable as a memory foam mattress? Go for it. Prefer a high-pressure start that backs off like a shy person at a party? That's your prerogative. The machine is your canvas, and pressure is your paint – just try not to get too abstract with it, or you might end up with something that belongs in a modern art museum rather than in your cup. Keep in mind though that you're accentuating some aspects of how a coffee pulls and minimizing others. 

Pressure Point Passport: Regions outside of 9 Bars

Now, let's hop on our caffeinated magic carpet and explore how different beans from around the world react to our pressure-profiling shenanigans. It's like international diplomacy, but with more delicious results and fewer awkward handshakes.

Take Ethiopian beans, the divas of the coffee world (and we mean that in the best way possible). These beans strut onto the stage with their bright, floral notes and acidity that could wake up your taste buds from a coma. But here's a little trick – pull them as a lungo with lower pressure, and suddenly that acidity mellows out faster than your cat after catnip. It's like sending your coffee to meditation retreat – still vibrant, but way more chill.

But before you go applying this zen approach to everything, let's talk about our friends from Southeast Asia. These beans are like that quiet colleague who surprises everyone at karaoke night – full of unexpected notes. When you start playing around with pressure, things get... interesting. Pull these bad boys at lower pressures, and their signature nutty, earthy characteristics start fading away. What you get instead is something that's a bit... well, plant-forward (that's coffee speak for "slightly vegetal"), with boozy undertones that would make a sommelier do a double-take. 

It's like these beans decided to go on a gap year and came back with a taste for fine spirits – think rum lounging in a garden, or cognac taking a stroll through an herb patch. Fascinating? Absolutely. What everyone wants? About as divisive as pineapple on pizza. 



The most difficult part of this whole process, is determining whether or not you should profile your beans at lower pressures. My advice is, pull a normal shot and identify what you like and don't like about it. Want a heavy texture but its too acidic? Sure bring the pressure down to 6 but only after you've kicked pre-infusion on for a few seconds. Then as the bag ages, you might not need that pre-infusion at all. Remember that the targets and guidelines are suggestions at this level of control. 

Puck Pressurization - A Guide to Pressure Profiling

To keep things short and simple, don't. Hard stop, that is all there is to it. If the look of your puck miraculously has an impact on the overall enjoyment of what is in your cup, it might be time to get a new hobby. The harsh truth is that the look of the puck after brewing has minimal to no impact on the overall taste in your cup. As for the "why," it takes a bit of historical knowledge and understanding of the current trends to make sense of it all which we'll diving into.

The year is 1961 and you're a spry espresso company located in Italy. Hot off the presses, you just created a new thermosiphon brewhead to use on your commercial espresso machine lines. Enter the E61, the iconic espresso staple still used to this day in home espresso machines. 

While it offers excellent temperature stability and pre-infusion capabilities, it also creates a unique challenge when it comes to puck analysis.

After the pump shuts off in an E61 machine, a vacuum is created in the brewhead. This vacuum effect causes residual water to be pulled back through the puck, effectively "destroying" its structure. As a result, what you see when you remove the portafilter isn't an accurate representation of how the water interacted with the coffee during extraction. This phenomenon can lead to false conclusions about channeling, distribution, or tamping technique. A puck that appears overly wet or shows signs of disturbance might actually be the result of the post-extraction vacuum rather than any issues during the actual shot. 


So should your pucks be wet or dry? It depends on the type of shot you are pulling. Not every puck will be perfectly solid, nor will every single one be soupy. While the Instagram and X posts might lead you to believe that every single shot is an aesthetically pleasing experience that tastes as good as it looks, that simply just is not the case. The slow dripping tiger striped shot you saw the other day and sent it to your significant other for the hundredth time more than likely tastes terrible and over-extracted. There have also been perfectly dialed shots pulled on Breville machines that I've had, which outclass many of the bean juice slurries I've gotten from many Linea Minis. 


If you're looking for an objective way to improve your espresso, unfortunately looking at your puck is sending yourself on a wild goose chase that will deliver mixed results and even less returns. Alternatively, if you're that engaged in the hobby, pick up a refractometer and learn what the proper tolerances are for your tastes. Personally I prefer anything near the 1.43 TDS which is around a 23% extraction. Once we can have a discussion about a 21% versus a 18% extraction, then lets talk advanced espresso. 

While puck analysis can be an interesting aspect of the espresso-making process, it shouldn't be relied upon as a primary indicator of quality. The unique characteristics of different machines, like the E61 brewhead's vacuum effect or the Flair58's low water volume, can lead to misleading conclusions.

Instead, trust your palate and focus on the elements that directly impact the taste in your cup. By doing so, you'll develop a more nuanced understanding of espresso extraction and ultimately enjoy better coffee. Remember, the goal is a delicious beverage, not a picture-perfect puck.

Caffeine Included.

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