The Impact of the “Pulse-Jet Technology” on My Espresso Extraction

In 2018 I experimented with the new “Pulse-Jet-Technology” from Nuova Simonelli in order to evaluate its impact on my own espresso extraction. I generally experienced, that extracting speciality coffee is a difficult task and requires high barista skills. Baristas are constantly looking for a harmonious taste balance, unique distinct flavors and great tactile qualities.

Within 20 to 30 seconds the barista either prepares the perfect cup or destroys the hard work of the entire coffee value chain.

New coffee origins, new coffee varieties and recently especially new post harvesting processing methods give nowadays even more flavor opportunities. In parallel customers are getting more educated and aware about the coffee flavors. The challenge is on!

To get out the maximum of a more and more complex coffee, you could so far manly work with the water quality, the water temperature, the grind setting and the brew ratio. Recently baristas have two more variables to work with: the water flow-rate and the water pressure. These two variables are - from my personal point of view - indirectly affected by the new “Pulse-Jet-Technology”.

Pulse-Jet-Technology: During the espresso extraction, you can now set for how long you inject water and for how long the coffee cake will rest. You might already be familiar with this way of brewing from your filter coffee preparation. Therefore you might have also already experienced, that this allows you to define the turbulences. In filter coffee this allowed me to maximize the desired flavors, complexity and balance in your cup.

The Aurelia Wave comes with three pre-set “Pulse-Jet-Scenarios” and in the future you will even have the option to manually set one scenario to give your barista the full control.

My setup: I worked with the Nuova Simonelli Aurelia Wave (incl. IMS shower heads and VST 20g baskets), a Nuova Simonelli MythosOne grinder, two Acaia scales (Lunar & Pearl) as well as a Pullman tamper. I measured each shot with a VST refractometer and calculated the extraction yield with the CoffeeTools iPad application. The sensory analysis was executed by a certified Arabica Q-Grader. I used an anaerobic fermented washed coffee from Finca San Luis in Colombia, that was light roasted by Vertical Coffee Roasters on a Diedrich. I measured the flow-rate inside the cup: 5 measurements per second were recorded with the Acaia scale and captures on “Brewmaster” iPhone application.

Technology check: Before starting to measure and evaluate the impact of the innovative “Pulse-Jet-Technology”, I tested the consistency of this new extraction methods. I conducted a total of 40 extractions with a 1:2.1/2.2 brew-ratio into double espresso cups. I set the temperature of T2 and T3 at 93.4 degrees Celsius and kept the grind size setting unchanged for all extractions. First I extracted 10 double with the Pulse-Jet disabled. Afterwards I extracted 10 double shots with the Pulse-Jet setting 1, then 2, and finally with the Pulse-Jet setting 3. I measured the flow-rate with an Acaia scale. For this test I measured the flow-rate inside the cup: 5 measurements per second have been recorded. After this successful consistency test, I moved on to the real experiment.

My protocol: I conducted a total of 25 extractions with a 1:2.2 brew-ratio into double espresso cups. I set the temperature of T2 and T3 at 93.4 degrees Celsius and kept the grind size setting unchanged for the first 20 extractions. First I extracted 5 double shots with the Pulse-Jet disabled. Afterwards I extracted 5 double shots with the Pulse-Jet setting 1, then 2, and finally with the Pulse-Jet setting 3. I have repeated the pulse-jet scenario 3 with a slightly coarser grind setting (0.4 courser setting on MythosOne), to achieve the same shot time compared to the other settings. I used this repetition of setting 3 for my final results and key take-aways.

My personal findings: I achieved a similar average TDS (8.9, 8.8, 8.9 and 8.9%) and calculated a similar average extraction yield (20.3, 20.3, 20.5 and 20.3%) with the different Pulse-Jet settings - no statistical significant difference. The standard deviations for dose-in, dose-out, TDS and Extraction Yield were also all very similar. Although the instrumental measurements of the solids showed no difference, I sensed a clear difference during the sensory evaluation:

No Pulse-Jet: The espressos brewed with no Pulse-Jet technology had a medium to high sweetness, a bright citric acidity, and a tea-like and grapefruit bitterness. I sensed flavors of citrus fruits, yellow stone fruits and cacao nibs. The body was medium, the finish slightly green and a little dry.

Pulse-Jet 1: The espressos brewed with the Pulse-Jet 1 were less dry, had less grapefruit bitterness, and a strong cacao nibs finish and clear notes of caramelized nectarine. I sensed also slightly more sweetness, a juicy multiple fruit acidity - like nectarine. The body was still medium.

Pulse-Jet 2: The espressos brewed with Pulse-Jet 2 showed a well integrated complex acidity, again higher sweetness, and intense yellow stone fruit flavors. The texture became creamy and I sensed a higher body. The finish was long lasting, lingering and sweet with notes of cacao nibs and cinnamon.

Pulse-Jet 3: The espressos brewed with Pulse-Jet 3 revealed the highest sweetness, bright and intense notes of yellow stone fruits, dried raisins, cinnamon and roasted hazelnuts. The body was bold. The aftertaste became shorter with a black tea and slightly dry finish.

My key-take-away: The Pulse-Jet technology allowed me to influence the flow-rate of my own espresso extraction. While the extraction measurements such as TDS and extraction yield remained unchanged from one Pulse-Jet setting to another, the sensory evaluation shows, that this new technology allowed me to alter my cup profile while keeping the standard espresso parameters unchanged (temperature, dose-in, dose-out, shot-time, grind setting). I am curious to hear about your experiences.