As a professional barista, you will have well and truly mastered the basics of producing great espresso. You’re probably itching to take on a new challenge and take your coffee to even more sublime heights.
You may not have considered the impact that brewing temperature has on the flavour of the espresso you produce. In fact, coffee is very sensitive to temperature — the same beans will have very different results in the cup if they are prepared at different temperatures.
You won’t be able to play around with brewing temperature unless your espresso machine is equipped with PID controls. In basic terms, PID controls are proportional, integral, derivative controls that continually monitor and then correct the brewing water temperature and make adjustments to keep this temperature constant.
The vast majority of espresso machines on the market are heated with the same heater element that produces the steam for steaming milk. The temperature of the brew water then becomes compromised between the optimum for extracting coffee and the pressure required from the steam wands. The brewing temperature will vary depending on a variety of factors, such as the number of consecutive shots and the amount of water used for flushing the group. Brew water temperature could vary by as much as 10 °C.
If you are lucky enough to have a Synesso sitting in pride of place on your espresso bar, then it’s a very different story! Synesso machines are widely touted as having the most stable brewing temperature of any commercial machine. Designed with a custom PID electronic system (known as Digizone control), Synesso machines allow you to adjust temperature by 1/10th of a degree.
In addition to the Digizone control, Synesso machines have a bunch of additional features which render their thermal stability the best in the business. The Synesso uses a brew water preheating system to prevent cold water entering the brew boiler, causing short term temperature instability. Each boiler is independently heated and controlled and is designed to ensure that thermal currents by way of convection prevent any cold or warm spots.
All of this means that you can easily experiment with the brew temperature settings on your Synesso to determine the optimum temperature that will extract the maximum amount of oils and flavour compounds from the specific Single Origin beans that make up your café blend.
Like most things in coffee, there are no absolutes. Taste is very subjective. There are, however, some guidelines that you should keep in mind when experimenting with brewing temps:
- Darker roasts and older coffee should respond to lower brew temps, due to more cellular breakdown already being present.
- Generally speaking, an increase in brewing temp will achieve a sweeter, fuller-bodied coffee.
- Reducing temp can help create a brighter coffee and accentuate levels of acidity.
The bottom line is, don’t be afraid to experiment. Keeping a log may be a handy way to remember some of your discoveries along the way.