Espresso and bikes go together like chocolate & peanut butter, Garfunkel & Oates, they go together like bikes & espresso. Maybe it’s because both bike and espresso enthusiasts have an appetite for finely crafted machines with tight tolerances and an interest in pursuing incremental gains through iteration of technique and materials. Or perhaps it's because both cohorts incessantly hunt that dopamine boost one gets from a long ride or from sipping an expertly crafted coffee. It's incontrovertible that there's much overlap on the Venn diagram. No matter the reason, we’re pausing the shop talk for ONE FREAKIN’ SECOND to take a look at crafting that ever elusive, perfect shot of espresso.
TL;DR. It's hard.
Coffee
Any discussion of espresso should start at the beginning with the coffee bean itself. Depending on what you’re going for, bean selection makes a huge difference in how your finished cup of black gold will turn out. Up until about 20 years ago, most espresso was made with dark-roasted beans (think Starbucks). The Italians pioneered espresso at a time (late 19th century) when nearly all commercially available coffee was dark roasted in order to mask the weak and inconsistent flavor of low grade, blended beans. This was an era wherein specialty, single-origin coffees weren’t widely available, if at all.
As the industry matured and connoisseurship of espresso became more prevalent outside the motherland (shoutout Primož Roglič’s ‘23 Giro d'Italia victory), coffee roasters responded to growing demand for a broader range of espresso experiences by developing lighter roasts and working more closely with growers of single-origin coffees. It’s now typical to be served single-origin, medium or lightly roasted coffee in most specialty coffee shops to such an extent that the majority of recent converts to the espresso game will know these options as default.
What do the differences in roast severity mean for the espresso they produce? Dark-roasted coffees typically have a bolder, heavier flavor due to the caramelization of sugars during the extended roasting process and can have chocolatey, nutty or smoky aromas, whereas medium and light-roasted coffees will preserve more of the original flavors of the bean and are often brighter and more acidic with floral and citric notes.
All of the above is a long way of saying Step 1: Get good coffee. We've been drinking a lot of single-origin Alta (Santa Cruz, Ca.), Verve (Santa Cruz, Ca.) and Ritual (SF, Ca.) at the shop lately.
Water Quality & Temperature
A critically important thing to think about with water, in relation to espresso, is its temperature. Most machines will default to 200° Fahrenheit (93.3° C). The hotter the water, the more solubles are extracted from the coffee. This makes sense in that the molecules in water move around more as the temperature increases thus, they slam into the coffee with a higher degree of frequency and force. Generally, lighter roasts tend to perform best with lower water temperatures (88°C to 92°C) and darker roasts perform best with temperatures on the higher end (90°C to 96°C). If your water temperature is too high, you’ll end up over-extracting your coffee. Too low and you’ll under-extract.
Many high end machines offer Proportional-Integral-Derivatives controllers (PIDs) which use algorithms to stabilize water temperature over the course of a shot, but often come at a significant price (although there are a few hacks online for specific machines). The other popular (and far less expensive) approach to regulating water temperature is to do what’s called temperature surfing (not as cool as it sounds brah, calm down 🤙). This works given that water temperature typically drops over the course of a shot. So, prior to puck prep (see below) the machine is run wide open sans portafilter in order to drop the temperature in the hope that by the time the puck is prepped, the temperature will be a bit lower than maximum hotness, and the shot can run hitting an average temp within the desirable range.
The other big lever you can pull with regard to water is the pH level. In order to get the most out of your beans, you’ll want to dial in the pH level of your water supply to ideally, somewhere between 6.5 and 7.5 pH. This is considered the optimum (neither acidic nor alkaline) range because it allows for balanced extraction of the various compounds in the coffee that contribute to the flavor; the flavor producing compounds are acids, sugars and oils.
Too low a pH level (acidic) and you’re apt to over-extract the acids yielding overly sour and/or bitter shots and, simultaneously, under-extract the sugars and oils yielding weak and underdeveloped espresso. A high pH level (alkaline) will lead to an under-extracted shot (in terms of the acids) resulting in dull/flat espresso, and may over-extract bitter compounds leading to harsh and unpleasant shots.
A responsible article would explain exactly how to change the pH level of your water supply if it were found to be outside of the ideal range. This is not such an article. The truth is there is no universally agreed on way to change the pH without affecting the flavor of the water, so if you find yourself meaningfully outside of the ideal range and are suffering from bad-tasting shots, you may consider using bottled water for your machine or installing a water filtration system (these options are both less than ideal for different reasons).
Some less expensive options include using a bit of baking soda to increase the pH level (like 1-2 grams/liter), and citric acid for lowering pH (half a gram per liter). Additionally, you can use distilled water, which has a neutral pH of 7, to not fully replace but to dilute your tap water as a means of mellowing the pH toward ideal from either direction. These solutions present their own challenges in terms of changing the flavor of the water, so it’s important to taste the water before you send it through your machine to make sure it’s palatable.
Step 2: Use good water, at an appropriate temperature. Not only will this result in tastier espresso, it’s also good for the longevity of your machine.
Tools
If you’re reading this you’re no stranger to coughing up some serious bread in pursuit of excellently crafted, high-performance objects (Reserve 77|Disc for example). In the world of espresso, much like the world of bikes, you’ll find no shortage of expensive machines and gizmos you can get mired down in, we hope to cut through some of the bullshit and provide an outline of the essentials.
You’ll need a decent grinder. A unimodal grind (one in which the distribution of the size of particles is narrow) has an outsized effect on the quality of the shot because it’s among the biggest factors influencing evenness of extraction; an even extraction is critical to a good-tasting, balanced shot, whereas an uneven extraction is present in many overly bitter, flat, undesirable shots. A unimodal grind is most easily arrived at with the use of metal burrs. Burrs are the part of a coffee grinder that actually does the grinding, essentially chewing the beans up into grounds and depositing them into the portafilter.
Step 3: Get a (decent) grinder with an adjustable, metal burr set.
It’s impossible to get a quality shot out of anything else. Also, look for something with stepless adjustments. A grinder with stepless adjustments allows for higher fidelity than its stepped counterpart when it comes to dialing in grind size (more on this below). One can expect to pay anywhere between $500-$4,000 for a decent-to-excellent grinder. There’s been a move in the direction of single-dose grinding as of late, and there’s nothing wrong with this. Beware, though, that many single-dose grinders jack up the price to do some things that can be achieved cheaply via retrofitting existing grinders with the help of the armies of 3D printers and craftspeople on Etsy, more on these hacks below. The advantage of a single-dose grinder is that it retains very little of the coffee during any given grind, so that what ends up in the portafilter is always freshly ground and not stale. This is more important for the home barista than it is for the cafe given the inherent volume differential.
Grind Size
Grind size is one of the most important factors contributing to an evenly extracted shot of espresso. Traditionally, a shot of espresso will take 30 seconds to extract at 9 atmospheres (bars) of pressure. If you’re confident that your machine is hitting 9 bars at the group-head but your shot is running in 35 seconds, grind coarser. The inverse is true; if your shot is running in 25 seconds, grind finer. Firstly, you need to be able to adjust the grind size in tiny increments of coarse vs. fine to get a good shot and secondly, you want the distribution of particle size as even as possible so that your shot tastes good. A wide distribution of particle size has the effect of smaller coffee particles being over-extracted, and larger particles under-extracted, resulting in suboptimal flavors as outlined above. It’s important that when you’re dialing in the grind size you change only one variable shot over shot. If you change the grind size and the dose amount, and the shot time changes, it’s very hard to determine which variable did what. Once you’ve got the shot dialed in to run in 30 seconds at 9 bars, you can toy with changing the pressure and run time, lower pressures yielding longer run times and vice versa. Step 4: Dial in the grind size.
Many grinders entering the market as of late have variable speed motors. The jury is still out on how this affects the resulting coffee. It’s been our experience to not have been pining for a variable speed motor setup. Time will tell.
Puck Prep
We’ve discussed above that a narrow distribution of grind size is helpful in getting an even extraction. Another thing that greatly affects the evenness of extraction is the dispersion of the grounds within the puck. If there are inconsistencies in the density of the coffee in the puck, the water will find them, and channel through them, resulting in uneven extraction. For many, many years, the status quo had been to rely on the grinder to disperse the grounds evenly in the portafilter. After grinding, one would tap the portafilter on the side to get the grounds to settle a bit, tamp and pull the shot. This works well enough if the grinder in use is of high quality as it will likely produce very fine, clumpless grounds. You’ll see very little in the way of puck preparation in cafes, both because they often use very expensive equipment capable of producing finely ground, evenly distributed coffee, and also because they aim to strike a balance between quality and throughput.
The home barista can afford to take more care in his or her puck preparation in favor of less expensive machines to achieve a similar outcome. One such way is to use a Weiss Distribution Tool (WDT). These can be found inexpensively online and are basically a few acupuncture needles sticking out of the end of a handle that the user swirls around in the portafilter, breaking up clumps. Another method is to use the Ross Droplet Technique (RDT). This is done by lightly misting the beans with aerosolized water prior to grinding them. The moisture has the effect of allowing the mild electric charge that beans pick up when being ground to dissipate. Less electric charge = less clumping. Check to make sure your grinder can handle a small amount of water passing through it with every use (stainless steel burrs and other components are essential here).
The last thing to do before pulling the shot is to tamp the grounds. As long as this is done evenly with about 40 lbs of pressure, it’s pretty hard to mess up. It's worth noting that once the grounds are tamped, you want to refrain from bonking the portafilter around too much as this can mess up the distribution, pulling the puck away from the sides of the basket...so tranquillo my dude...take it ease.
Beans In vs Espresso Out
Most espresso aficionados will learn to pull shots by aiming for 1 : 2 :: beans in : espresso out by weight. Step 6: Use a scale. Don’t rely on volumetric measurements. Both coffee beans and espresso have differing weights by volume depending on many factors–although it’s mostly the degree of roast, ergo density, that comes to bear on this. After you’ve dialed in the grind size such that you’re getting that 1:2 ratio consistently, you can start to look at things like adjusting the pressure (to change the runtime) and pre-infusion (pressure profiling) depending on your desired outcome. The world of pressure profiles is an interesting one, and many espresso machines priced at the high end of the market allow users to modify these parameters to achieve all kinds of exotic results. We won’t go too far into depth on that subject as it’s not necessary to pull a good shot, more of an advanced technique.
Step 5: Prep the puck.
Yield/Time
Step 7: Use a timer.
The ideal extraction time and pressure for an espresso shot depend on a combination of factors, including grind size, dose, coffee beans, and equipment capabilities. Aiming for a 30-second extraction with 9 bars of pressure is a good starting point for many setups, but adjustments might be necessary based on specific circumstances and desired taste profile. Obviously time and pressure are interdependent variables, low pressure = high time, and high pressure = low time all else being equal (grind size, dose). Most espresso heads will tell you that a shot of espresso shouldn’t take much less than 30 seconds but they won’t tell you that it shouldn’t take much longer than that if the pressure is lower than the standard 9 bars. The best practice is to consistently get that 1 : 2 ratio in 30 seconds at 9 bars, then begin to play with the other variables such as pressure profiles.
Step 8: Make some espresso.
Conclusion
We’ve covered a lot above in an admittedly long winded way, but it is by no means a comprehensive guide to brewing the perfect espresso. The truth is no such guide exists. This might sound like a postmodern copout–but it’s not. As is found with many things worth pursuing; the more you learn, the less you know.
We’re aware that all of this sounds complicated…it is. It's as complicated as you want to make it. The observant reader might have noticed that there's no scale, no timer, WDT, RDT or any of that stuff pictured in this article because we didn't use any of those things when we were taking these photos and the drinks we made turned out pretty, pretty, pretty good despite that fact.
The best plan of attack? Set your sights on one variable at a time, give yourself some room to fail (and some inexpensive coffee to fail with), be open to new information–pragmatism over dogmatism–and know that much like cycling, the journey toward perfection is asymptotic over time. No matter how hard you try, the perfect shot of espresso will remain elusive, so you may as well enjoy the ride or at the very least wake up and smell the coffee.