Understanding Your Brew Pressure Gauge

Learn more about the brew pressure gauge on your vibratory pump espresso machine and how it might affect the shots you pull.

"My machine isn't building enough pressure."

"What are these gauges for?"

"My machine doesn't have the pressure that it used to."

If you've found yourself wondering about your espresso machine's brew pressure (whether it's new or used), we're here to help! In this article I'd like to offer some straightforward clarification so you can zero in on great shots faster and save yourself a phone call or email.

All of our vibratory pump espresso machines are capable of pulling shots at the commercial standard of 9.0 Bar or 130 psi brew pressure. Whether your espresso machine has a brew pressure gauge or not, this is a constant you can count on. The next logical question is, why do some machines have a gauge displaying brew pressure? The gauge is largely there to show us if the brew pressure needs eventual adjustment or when it's time to replace the pump.

If you've ever wondered "Is my machine building enough pressure?" and the gauge is displaying lower than 9 bar when brewing, then it's time to focus on the brew ratio and time. If your brew pressure looks low, your shots are likely flowing too quickly (this will lead to a variety of off flavors). So break your eyes away from the brew pressure gauge and get out your stop watch (many espresso machines have shot timers built in or available to install) and scale.

Simply put, as a home barista your top priority is to verify that your grind is fine enough that your 18-20 gram dose (depending on whether you're using a double or triple basket) results in our recommended starting point of 30 grams of liquid in 25-30 seconds. While a healthy espresso machine pump will always achieve the brew pressure it's been adjusted to put out, the gauge is only able to display this when it meets sufficient resistance. Want to verify this? Just insert your backflush disc or blind basket and activate the pump. Within approximately 10 seconds you should see the full brew pressure displayed. Backflushing will display a slightly higher pressure than what you'll experience pulling shots, so don't fear if you see around 10 bars on the gauge. The pumps in commercial machines are set to 9.8 Bar in order to achieve a consistent 9.0 Bar while brewing espresso.

When you stop the pump after seeing full pressure, it's very normal for the needle to land at different places at different times (it does not need to rest at zero). Keep in mind that brew pressure gauges only provide meaningful information when the pump is activated and meeting sufficient resistance (such as a backflush disc or a properly prepared shot). If your pump achieves recommended pressure during backflushing, but not when pulling shots, it's a fair bet that something in the preparation process is amiss.

The three key components to getting the most out of your vibratory pump machine are: roast date, grind quality, and puck preparation. In order to brew good espresso, you need good coffee. We recommend using coffee that's within 5-11 days of its roast date. If there's no roast date on the bag (a "best by" date doesn't count) or if the coffee is older than a couple weeks, there's not enough lingering CO2 in the beans to yield the rich crema that everyone raves about. Similarly, espresso must be ground to order. Coffee can lose all of its zest as soon as a minute or two after being ground—so pre-ground coffee just won't do. And don't even think about using a blade grinder! Consider investing in a quality espresso-dedicated grinder to really allow your machine to shine. On the other hand, the right accessories are a matter of personal choice. Take some time to find a good set of barista tools that you enjoy using.

"Does my pump need to be replaced?"

Vibration pumps are robust little units, but after 4-5 years of stalwart service they will inevitably fail. Failure is evidenced by a change in pitch and needing to adjust the grind significantly coarser. If you wonder whether your vibration pump needs replacing and your machine has a brew pressure gauge, backflush as above and let us know if your brew pressure is significantly below 9 bars.

Rotary pumps should go for many years without needing adjustment. One thing to be aware of when switching your rotary pump machine from reservoir to plumbing mode, is that the addition of line pressure may push your brew pressure above 9. Make sure you have an inline pressure regulator adjusted to 30-45 psi. You may still need to adjust your brew pressure down slightly, and we have instructions available.