DIY Coffee

Chapter 4. Hot on the Spot

Photography by John F. Murphy

Get consistent shots by adding precise temperature control to your espresso maker.

By John F. Murphy

The art of espresso making is fraught with many variables — coffee bean origin and blend, degree of roast, fineness and consistency of grind, tamping force and technique, and on and on and on. The temperature of the water used to brew the shot is one of the most important variables. In most espresso machines, the brew temperature is controlled by a wildly inaccurate thermostat.

However, control over the brew temperature is key to espresso quality. Different blends of espresso beans and different degrees of roast develop different flavors when brewed at different temperatures. Malabar Gold may taste sweet at a temperature that makes DSB taste sour. Control over the brew temp allows the skilled barista to coax the best flavor from each blend and each roast. In a stock Silvia espresso maker, relative brew temperature is roughly guestimated by “time surfing,” or pulling the shot a certain number of seconds after the stock thermostat turns on the heating element. Surfing does work, but it requires careful attention and lacks accuracy.

A better way is to use a PID controller. It’s easy to use (just set the desired temp and let the PID do its thing) and highly accurate, meaning the brew temperature of the next shot can be very nearly the ...