Slayer uses a completely new approach to brewing espresso that results in shots that reveal more nuance and complexity in the cup than is ordinarily experienced from coffee prepared as espresso.
Variable brew pressure control lies behind the remarkably detailed flavors you experience from coffee brewed on the Slayer. Slayer enables the barista to work with much lower pressure in a pre-brew phase before extracting the espresso with full pressure.
Slayer’s dynamic pre-brewing functionality is key to controlling a coffees unique characteristics to achieve specific flavor profiles in espresso, since every coffee has a unique set of pressure parameters that reveal the best the coffee has to offer, in terms of sweetness, brightness, body, and unique flavor notes.
Why does lower pressure make such a difference? Pre-brewing allows the coffee in the portafilter a chance to gently expand and release aromatics before it even starts to flow into the shot glass. During the pre-brew phase the espresso is undergoing a transformation, similar to that of coffee brewed in a French Press.
For a period of time directly related to the particular coffee being prepared, the barista will allow the ground coffee in the portafilter basket to become fully saturated. The amount of pressure applied during pre-brew is usually around 3-5 bars--but the exact amount of pressure is specific to a large degree on the coffee being prepared.
After a period of 15-20 seconds, the barista applies water at full pressure to the coffee. At this point you can actually see espresso begin to pour into the shot glass. For certain coffees, it is desirable to slow the flow rate during the pour, by reducing pressure towards the end of the extraction. Whether or not to reduce pressure in this way and for how long depends entirely on the flavor characteristics that are being highlighted in a particular coffee.
Preparing espresso this way relies on the knowledge and hand of the barista. It is a manual process. General brewing parameters can be developed for a particular coffee. However, the barista must still make adjustments for each coffee, to account for changes in conditions of weather, and even the age of the coffee beans as they are used over several days.
As shots are developing you will see the barista watching the extraction carefully, even while steaming milk. Slayer is designed with a strategically positioned mirror, so pours can be monitored easily without having to stoop down to look directly under the grouphead.
The extreme control and gentleness of Slayer’s brewing process allows the use of single origin coffees that would not ordinarily be prepared as espresso.
Eric Perkunder
Slayer, Engineering & Design
