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Descaling a La Pavoni Professional

Every now and then your espresso gear will need cleaning. You wash the portafilter and baskets after every use, clean the driptray at least once every few days (i hope) and wipe down the rest of the machine every so often. But what about the inside of the boiler? You can’t just reach in with a brush and start scrubbing around. Well you could but it’d be a lot more trouble than i would want to go through. Especially on a Tuesday morning before (!) i had my first espresso.

Sometimes my La Pavoni Professional ends up looking like this after pulling a shot of espresso. It’s dirty and obviously needs some cleaning, but all that is mostly cosmetic. The inside of the boiler however is looking like it needs a bit of attention too.

As you can see there is quite a bit of calcium buildup on the heatingelement (the coil at the bottom) and the walls of the boiler. There is however one very important other part that you cannot see but is very affected by calcium buildup, the pressostat. The pressostat measures the pressure inside the boiler as the water temperature rises. If the accessport to the boiler clogs up with calcium the pressostat can no longer get a clear reading on the pressure in the boiler which can cause the boiler to overheat, which is quite dangerous. It’s also possible that a false reading will shut the heatingprocess down prematurely, which prevents the water from actually getting up to operating temperature and will make your espresso’s sour and weak.

Descaling

There are a lot of ways to descale, some people use vinegar (diluted or undiluted) but a common practice is to use pure citric acid. You can buy it at most drugstores, but be sure to check that it is purely citric acid and doesn’t contain anything else! A little heads-up, do not eat or drink it, get it in your eyes, open wounds or anything else because the stuff is not good for you. If you accidentally spill it on the chrome of your La Pavoni, wipe it off immediately because citric acid will damage chrome (not instantly but it certainly doesn’t do it any good)! Keep a couple of paper towels handy. Keep your workstation, tools and accessories clean.

Anyways, enough with the lecture, lets clean. I emptied the boiler and mixed a liter (4 1/4 cup) of handwarm tapwater to 50 grams (1 3/4 ounces) of citric acid powder. Then, using a plastic or stainless spoon, stir the whole thing until the powder has fully dissolved into the water. I poured a little bit of the solution into a little glass bowl to descale the single basket. Normally this isn’t necessary if you clean it after every shot pulled (like you should) but because it’s stainless steel i figured i’d give it a go. Pour the rest, carefully, into the boiler.

After filling the boiler put the boiler cap back on and switch the heatingelement on. When the pressure starts rising (or when you hear the pressure-relief valve hissing if you don’t have a pressure gauge) switch the machine off and let it sit for a while. Depending on the amount of calcium buildup that can be anywhere from half an hour to 3 hours. If you feel inclined to check if the progress make sure there is no residual pressure left in the boiler by opening the valve to the steamwand.

Never let the Citric Acid solution enter the grouphead or steamwand

The inside of the grouphead on the La Pavoni Europiccola and Professional is also chrome plated. If it comes in contact with the citric acid the chrome will start chipping and flaking off. The surface inside the grouphead is where the piston and its rubber seals slide along, if that surface is damaged the seals will eventually start leaking and simply replacing them will be nothing but a temporary solution. Eventually you will have to remove the grouphead and have it re-chromed or replaced, not cheap.

Cleaning some more

While the citric acid solution is doing its job i cleaned the chrome body, base and grouphead with a damp cloth and washed the portafilter and driptray. One other important part that you will want to check on regularly is the bottom of the grouphead. La Pavoni owners will know that it takes a lot of tinkering to figure out the correct grindsetting, amount of grounds, tampingpressure, grouphead temperature, pressure on the lever and who knows what else. Every so often we mess up and get the infamous portafilter sneeze, which means there’s still residual pressure left in the grouphead after pulling a shot that we have no way of relieving (other than to leave it alone for a while). The portafilter sneeze creates an enormous mess and while most can be clearly seen, chances are you’ll forget the grounds in the bottom of the grouphead. I draped a damp cloth over the base and ran a brush through the bottom of the grouphead until it was clean. As you can see there was quite a lot in there, even though i clean it regularly.

Rinse and repeat

I check the boiler every 15 to 30 minutes to see if the calcium buildup has disappeared. If it has, as you can see in the pictures, i empty the boiler through the top. Then i fill it about 1/3rd, put the cap back on and shake it like a cocktailshaker. After a minute or so i empty the boiler again through the top and put some fresh warm water in it. I do that 2 – 3 more times, until i am sure all the contaminants and flakes of calcium are out. Do it twice more if you have to, you can’t do this too much. Make sure the lever stays down at all times, we don’t want water all over the kitchen.

Now i’m satisfied with the inside of the boiler i still want to purge the grouphead tube, the grouphead and the steamwand by filling the boiler with water and heating it the way i normally would. When the boiler has reached operating temperature, i switch off the heatingelement and put a little kettle under the grouphead (on a piece of cloth to minimize the risk of damaging the chrome) and in short bursts empty the boiler until the waterlevel in the sightglass almost touches the bottom of the sightglass. I then let the La Pavoni cool down and do the same thing a second time, maybe even a third time if i’m not satisfied with the clarity of the water coming out of the grouphead yet.

As you can see i had the portafilter with a single basket locked in the grouphead, if you don’t have a bottomless portafilter do not use it while purging the grouphead, the water will shoot out of the spout(s) and end up on the walls left (and right) of the machine, not in the kettle. The only reason i locked it in was because i wanted to flush some water through the basket that had been in a citric acid solution as well.

Conclusion

Well the conclusion is pretty simple, the tank is clean and at exactly noon i finally had my first espresso of the day. It also took me a lot longer to write this post than i imagined it would at first, but if it helps anyone that’s all i care about. For now have fun tinkering with the various variables that make or break your espresso shots on a freshly cleaned La Pavoni, i know i will.

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