We've only had a few days experience with our new espresso machine, but I feel confident in saying that the Strada is a lovely can of worms. One I'm happy to open, and at the same am terrified of. Pressure profiling, or as we call it, "the dark arts", is something that has largely interested and intimated me. Each day behind the bar, we strive to remove any unnecessary variables from our working environment. So to open the door for endless variables and possible inconstancies, just seemed "wrong". We shouldn't have been surprised then that, like all things that seem "wrong", pressure profile is awesome and highly addictive.
We were fortunate enough to be able to hook up the Strada along with our Robur on Monday at the Metropolis lab. Our first shot, Metropolis's El Salvador La Fany, ran a bit slow and the first attempt at controlling the paddle was not unlike driving a Mack truck-white knuckles, sweaty palms, and a little bit of pee in your pants. A grind adjustment or two later, we were pulling good volume and time with a fairly moderate extraction rate.
Then it was nerd time... We pulled a few shots, dissected the phases, and took note. The La Fany had impressively buoyant body and really intense acidity. At a standard triple basket extraction, (21g, 200.5F, 23 sec, 1.5oz), with no pre or post infusion, the acidity was overly sharp and heavy, the finish a bit astringent, and overall, the coffee lacked clarity. The body was, in my opinion, perfect. However, I tend towards a syrupy mouthfeel, so to be less subjective, the body was almost obnoxiously thick. The dissection showed that the first phase had body like an anvil, but nice soft sweetness. The second phase was like sucking on a lemon with a sore throat. Easy enough fix, we dropped the dose a couple grams and introduced a 3 second pre-infusion at 3bars with a ramp up to 9 thinking this would surely take a few pounds off the body and probably dull the acidity a bit. Nope. The body thinned for sure, but the acidity was still a nightmare. Time to evoke evil. We kept our pre-infusion time, added a ramp down to 6bars at 17 seconds, and a slow kill at 22 seconds. The result was liquid "doing it". The body was still there and the acidity had rounded out to the point of being more like a mandarine orange, as opposed to the unripe lemon it was, thus allowing the sweetness to come through with great clarity. The cup was sweet, clean, and complex, all with a small adjustment of the paddle. Ef-ing scary. We dissected the new parameter and found that the first phase did, indeed, have a more palatable body. It had also lost a bit of sweetness, but.. eh. The second phase, now experiencing a pressure drop, was a different beast entirely. Not much lost in body, but the sharpness was 97% gone. The third phase was also cleaner, almost unidentifiable.
Suddenly, it all made perfect sense, painfully obvious even. The days of simple dose/grind adjustments, temp surfing, and basket swapping in order to achieve a desired flavor profile are officially becoming archaic. Being able to pinpoint specific moments of the extraction where you'd like to change the rate is an amazing feature. I felt like a 80 year old, sending my first email, like I'm living in the future. Though some of my previous thought on pressure profiling remained. In the wrong hands, it could be a dangerous tool. Though once you've played around with it, the effect that pressure has on extraction is simple to grasp. If you've ever turned the stereo up during your favorite part of a song, you pretty much get it already.