Refresher: Preventative Maintenance

As many of your are off work this week, we thought we’d take the opportunity to give you some reading material ”save it for later if you want. No matter how experienced you are, or how much of a newbie you may be, every coffee professional needs to stay fresh on these critical parts of the job; sure, it’s less sexy than pulling a beautiful shot, but it’s how you’re  able to pull a beautiful shot.

Today’s topic is preventative maintenance, i.e. how you can keep your coffee equipment running smoothly, and as a result, save yourself thousands in repairs and replacements in years to come.

Stumptown Coffee’s lead tech Alex Lambert shares some easy to follow tips for keeping your espresso machine and grinder running like the champs they are. Also, we’re offering a handy monthly schedule you can print out and tack up in your shop at a reminder. Enjoy!

By Alex Lambert, Stumptown Coffee, Portland, Oregon

Baskets “ If they are excessively bowed on the bottom and no longer flat, if you see creases in the corners, or if the top edge of the baskets are dented or deformed in any way it’s probably past time to replace them.

Basket springs “ Do you have problems with your basket falling out every time you knock out a puck? Time to replace those springs. Don’t use a paper clip, they are usually not the right diameter and are a pain to bend into the right shape anyway. The real springs are extremely cheap. You should always use the proper ones for your make and model of machine.

Steam Valves “ If they are leaking, if the flow has changed noticeably (usually on the slower side), if they are feeling difficult to turn the knob or actuate in any way, or if the steam smells bad (indicative of poor cleaning or purging practices) then they need to be rebuilt immediately.

Burrs “ This is a tough one to judge, but a little math can usually help. Most grinder companies can give you a rating in pounds or kilos that the burrs can handle. If you want to always be on top of it, you can go ahead and replace the burrs at about half that rating. For example if the rating is 800kgs, I would recommend replacement at 400kgs or so. If you have a good idea of the average number of pounds per week that you go through in espresso, you can figure out roughly how often to replace them.

Burrs that are in bad shape will cause all kinds of issues, such as erratic grind particle size, incon- sistent dosing on grinders that dose based on time or burrs jamming up. The coffee coming out of a grinder with dull burrs will likely be hot to the touch as well, which degrades the coffee and therefore your espresso. Even if you don’t go through enough coffee to change your burrs more than every couple years, it is a good idea to take apart the grinding chamber and clean it out on a regularly scheduled basis. I recommend every six months to a year at the latest).

Pump Pressure “ Make sure the shot pressure gauge is reading nine bar when you are pulling a shot. When you are not pulling a shot, the pres- sure will travel around between one and 12 bar. If it’s going above 12, you may have a faulty or out of adjustment expansion valve. If the pump doesn’t hit nine bar every time you do pull a shot, then the pump or motor may be bad.

Temperature “ Depending on the type of machine you have (heat exchange, dual boiler, etc.) you may be able to check the shot temperature at the group and make adjustments if necessary. On dual boiler (or individual brew boiler machines) like a La Marzocco or Synesso, there will either be a thermostat or a PID setup controlling your brew temp. To get a truly accurate test of temperature you will need a special thermofilter device known in the industry as a scace (named after the device’s inventor Gregory Scace). The instruction manual for this device is pretty heavy reading, but contains some of the most detailed and helpful informa- tion out there on how to get a proper and accurate reading on your machine. The whole process usu- ally takes me about an hour to do, but it gives you a really great idea of not only how accurate your machine is at any given moment, but how well it sustains its temperature accuracy over the course of a simulated busy rush. A hefty investment is required as you would need both the scace device and some kind of thermometer to plug it into such as a Fluke 50 Series, but it’s worth it if you want to be super accurate.

Gaskets “ Brittle, hard, dry, cracked, or leaking gaskets should be replaced. To be truly preventive about it you should replace them before they get this bad.

Screens “ If they are smashed or look at all dam- aged, for example if the mesh is separating from the rest of the screen, or if there is obvious coffee build- up they should be replaced. I recommend replacing screens well before these signs are apparent.

Critical Listening Time “ If you are doing a preventive maintenance session, it’s helpful to eliminate as much extraneous noise from the room as possible. This is because an espresso machine can tell you a lot about how it is running with some subtle sound cues. Listen closely to your machine. Do you hear hissing coming from inside? If so, it probably has a steam leak somewhere. Hear some- thing buzzing or rattling? Could be a failing brew valve or contactor. Is the pump or motor making a lot of noise? You may have clogged water filters or a failing pump system.

Visual Inspection Time “ Check underneath your machine and look for any signs of water pooling on the counter. Typically if the water is clear and clean, you should suspect a leak in the machine. That means it’s time to open her up and inspect around all the fittings for wetness and or actual water dripping. This is also a good time to look for signs of scale buildup around any fittings.

If you notice calcium building up on the outside it’s a relatively safe bet that there is calcium buildup inside the machine as well. If there is dirty brown water under the machine (assuming the counter under your machine is nice and clean) then that usually means there is some problem with the drain setup. Is there a crack in the drip tray or drain box? Is the drain box full and not draining quickly? It could be that the drain tube is clogged or sagging somewhere allowing grounds to build up and block the tube. The best/worst way to clear this up is to remove the tube and blow through it. When you reconnect it make sure it is pulled snug and doesn’t have any dips or kinks and has a good downhill slope to it.


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About Sarah 934 Articles
Sarah Allen (she/her) is co-founder and editor of Barista Magazine, the international trade magazine for coffee professionals. A passionate advocate for baristas, quality, and the coffee community, Sarah has traveled widely to research stories, interact with readers, and present on a variety of topics affecting specialty coffee. She also loves animals, swimming, ice cream, and living in Portland, Oregon.