Prime numbers. Prime rib. Prime rate. Optimus Prime. These are just a few of the primes we know and love, but if you’ve ever spent some quality time with an espresso machine, priming is another prime that you’ll learn to appreciate.
The phrase ‘prime the pump’ is often used to describe things not quite so literal (it’s a particularly popular phrase used in reference to economics) but exists for a reason: By adding something to a system, you can facilitate action. In the case of today’s SCG Tech Tip, it’s adding water to a pump to force any air out of it and start the pump processing water from the reservoir or main line to the machine’s internal boiler and related waterworks.
Espresso machine priming occurs primarily with new machines, which don’t have any water in them, but a machine that has had its boiler drained (for shipping or long term storage) or machines that have sat awhile may also require priming.
To prime the machine, you open either the steam or hot water valve in order to encourage the pump to draw water from the reservoir and fill the boiler system. This is the tender way of doing it, but sometimes an espresso machine is a bit stubborn (read: It somehow got air pockets in its water lines, making it difficult for suction to occur) and you’ll have force the issue — literally. Using a tool like an ear syringe or turkey baster, you force water under pressure into the water intake area while engaging the pump; this gives the machine the extra oomph it needs to prime itself.
To learn all you ever wanted to know about espresso machine priming, we asked Brendan to break it down for us in the priming primer! He talks with us about what priming is, how and why you do it, then gives us a few tips and tricks to help the process go smoothly.