This article is part of Cartel's "Educational Series", written by Drew Scharnitzke – our Director of Education. To access our full educational resource library, visit this link.
Over the last year, Cartel's espresso parameters have given guidelines to target proper extraction for the coffees we feature as espresso. Although the parameters allow the coffee to be within the extraction target range, the flavor profile changes over time as roasted and green coffee age, temperature and time of year change, and as we anticipate new arrivals of coffee offerings. That being said — I would like to generally address the dialing in process and the theory behind doing so efficiently while utilizing the parameters as a tool.
Acknowledging our input variables (time, temperature, pressure, grind size, and ratio) is the first step in properly dialing in. Espresso machines are designed to maintain two of the five input variables. Temperature and Pressure (agitation in filter brewing) are theoretically consistent when brewing espresso.
Having variables that do not change offer the ability to make quick, efficient, non-confusing changes to the way the espresso is brewed. Consistently changing multiple brew variables at a time will often lead to confusion, frustration, and improperly extracted espresso.
Ratio, time, and grind size are the three main factors to consider while dialing in. However, with our brew parameters, ratio is taken care of with the input set at 18g and output at a range, typically somewhere between 36-42g out. At this point, time and grind size can be targeted to manipulate the behavior of espresso shots by fining the grind setting to achieve a slower flow rate or coarsening the grind to achieve a faster flow rate. Using grind size, you can determine how quickly your pre-determined output weight is brewed.
In regards to extraction: "The problem with relying solely on taste is that many variables in the espresso-making process have nonlinear effects. These nonlinear effects make it nearly impossible to find the optimal set of adjustments through trial and error guided by taste alone” (Scott Rao). With this evidence, I would like to emphasize the importance of parameters, or at the very least, setting static variables. The only way to measure your extraction window is by first measuring the concentration of an espresso and then multiplying it by the brew ratio. That being said, even if you are dividing your output by your input, you are not measuring your extraction; you are measuring your ratio. If we all had the ability to utilize refraction technology on a daily basis to dial in our espresso, I would highly encourage adjusting input variables as you choose. However, because we are not able to logistically handle that practice, I encourage the use of the parameters as your “safety” range. By only adjusting 1 to 2 parameters at a time, you will find more consistency and ease in your dial in!
Baristas: The next time you dial in, consider this. Target your desired time first. Choose three different output weights (or times) to stop the flow of your shot. Taste your shots and determine which tastes best. Then consider “development” time. Keep in mind that if the shot is sour, "Espresso is typically sour and unremarkable at 17.0%. The shot with the finer grind may have been 17.7% and perhaps marginally worse-tasting than the first shot. Had the barista made the grind finer again to create an 18.5% extraction, he would have noticed an increase in ripeness and caramels and a decrease in sourness.” (Scott Rao). Focus less on the perceived “extraction” and more on the actual flavor development. I highly encourage experimenting with dialing in focusing on various input variables. However, for the sake of recipe and store to store consistency, I would advise keeping within the range of the parameters.
Not Baristas: Consider this an overload of information that might not mean a lot to your daily life. However! Speak with a barista about anything you would like to further your knowledge on. Maybe drink some espresso if you normally don’t. Maybe have your barista tell you their parameters.