PID controllers and multi-boiler technology
Prior to the introduction of multi-boiler machines with PID controllers, espresso machines often relied on a single boiler with a heat exchanger inside to allow the user to simultaneously extract espresso and steam milk. The temperature control on these machines was analog and rudimentary at best using a pressure-stat (similar to how a thermostat works, but with pressure instead). Basic high school science tells us there is a linear relationship between pressure and temperature. That is to say, if the pressure goes up, so does temperature and vice versa.
Whilst heat exchanger machines work perfectly fine for the most part, during the early 2000s there was a concerted effort from home coffee enthusiasts to better regulate extraction temperatures of their machines. What some people did was take temperature controlling equipment often found on industrial equipment like kilns and ovens and retrofit that to their espresso machines to give them more finite control over the brew water temperature. This controller is called a PID controller, which precisely controls the temperature based on an algorithmic feedback loop and input conditions.
The introduction of PID controllers to espresso machines was a revolution and machine manufacturers from around the world sat up and took notice. By the mid-2000s, espresso machines from companies like La Marzocco and Synesso were either being retrofitted with PIDs or designed with inbuilt PIDs.
Thanks to incredibly smart people sharing ideas on the internet, most manufacturers of domestic and commercial espresso machines have PID controllers in their lineup. All of the barista courses at The Espresso School are conducted on multi-boiler PID or heat exchanger machines.
Doserless electronic grinders
Another place people started to look at to improve espresso production was the grinder and its management.
It’s common street knowledge that better coffee starts with freshly ground coffee, so baristas were starting to use grinders in a way they were not intended to be used.
Traditionally, espresso grinders had an entire chamber full of ground coffee waiting to be dosed out. 3 pulls of a lever and you’d have a basket full of coffee ready to be distributed and tamped. Baristas then started to use coffee grinders in a way they weren’t intending to be used – grinding only a small portion of coffee as needed by turning on and off the grinder manually and then repeatedly pulling the dosing lever in excess of 20 times to remove all the grinds from the dosing chamber.
From an efficiency and ergonomics standpoint, this was obviously slow and lead to a lot of repetitive strain injuries.
In the mid-2000s, baristas were starting to modify their grinders by retrofitting electronic timers and replacing dosing chambers with funnels so they could grind directly into their filter baskets without the intermediate step of having to pull a lever.
Eventually, companies like Mazzer came to the party and baked in this tech directly into their grinders and other companies followed suit. In today’s market, doserless electronic grinders are ubiquitous with cafes around the world. All barista courses at The Espresso School are conducted on these modern grinding systems.
Precision filter baskets
After essentially maxing out the technical capabilities of espresso machines and grinders in the mid to late 2000s, the focus of the barista fraternity moved towards one of marginal gains.
An often under-looked piece of critical brewing equipment is the filter baskets. Most machine manufacturers often sourced baskets from one of a few OEM manufacturers and threw that in with their machines with little regard to quality.
Baskets that came with a machine often had assorted quality control issues like improperly sized diameters causing tampers to jam inside baskets and partially or fully blocked holes on the bottom wall. Whilst the former might be mildly annoying from time to time, the latter issue often caused espressos to extract wildly unevenly.
To fix this, companies such as VST and IMS started to manufacture filter baskets with measurement perfect diameters and perfectly even filtration holes allowing baristas to extract coffee to its full potential. Every machine at The Espresso School is fitted with IMS E&B Lab precision filter baskets.