Hi everyone,

Brief Summary
Is it safe to descale my Profitec Pro 300 after 8 months of making 2-3 espressos a day using hard water (320 mg/L)?

Longer Explanation
I've had my Profitec Pro 300 for almost 2 years. For the first 15 months I lived in Minneapolis where the tap water is not very hard (around 65 mg/L), so I filtered the water with my Brita filter and used that in the Pro 300. For the past 8 months I've lived in a town with much harder water, around 320 mg/L. Unfortunately, I didn't realize how hard the water was until I tested it today with Hach strips and then looked at my town's annual water report: https://www.ci.northfield.mn.us/Documen ... 10_2019-v2. (I did test the water when I first moved to town, but I must have misinterpreted the results and thought it was much lower hardness at the time.) I'm not sure what the breakdown of hardness and alkalinity in the water is.

I'm happy to switch over to a homemade water solution and if necessary do preventative descaling going forward, but now I'm worried about scale build up in the Pro 300 after 8 months of making 2-3 espressos (including 1 cappuccino) a day with very hard water. On top of that, Clive Coffee warns me from descaling the machine myself. While the Pro 300 manual gives instructions for preventative descaling, it warns that "An already calcified machine may only be descaled by your specialised dealer because a partial disassembling of the boiler and the tubing will be necessary in order to prevent the system from being blocked by lime residues. A late descaling can cause substantial damage to the machine."

The last thing I want to do is ship this machine to Clive for a descaling. Is it really unwise to descale it with a mild citric acid solution as suggested in Schulman's Insanely Long Water FAQ? From the FAQ, I'd estimate my machine accumulated 1-2 grams/month in scale over the past 8 months, though it's hard for me to estimate because I don't know the actual breakdown of hardness and alkalinity.

Thanks!
Jason

Here's an update. I've made up a batch of Pavlis water following this recipe:

- concentrate = 16.1g sodium bicarbonate to 750ml distilled water
- water mixture = 1 Tbsp of concentrate to 1 gal of distilled water

I flushed out the hard tap water that was in the machine and now have the Pavlis water circulating in it. The shots taste extremely smooth but kind of flat. They don't taste bad, but I don't get the more interesting flavor notes that I got with harder water.

In this post homeburrero says that a low hardness water with a negative LSI would in effect be "constantly doing a safe, acid-free prophylactic descaling of the machine." Would that also apply to the Pavlis water I'm using? My concern in my first post was whether it was safe to descale my machine after 8 months of using very hard water, but maybe this Pavlis water would gently descale my machine anyway. If that's the case I'm killing two birds with one stone.

Thanks,
Jason

fushifushi wrote:In this post homeburrero says that a low hardness water with a negative LSI would in effect be "constantly doing a safe, acid-free prophylactic descaling of the machine." Would that also apply to the Pavlis water I'm using?

The rpavlis water, being far undersaturated for CaCO3 (limescale) should tend to dissolve limescale. But at an extremely slow rate. One way to think of it is to consider a crushed marble (calcite) remin filter, which is primarily just CaCO3 . If you run calcium-free soft water through it it will dissolve some of that CaCO3 of the marble. The feedwater is constantly 'descaling' the calcite filter. But at a slightly basic pH like you have in that rpavlis water very little of it dissolves, and that's for crushed media. For thick limescale without much surface area I suspect it may take years to dissolve. But you can assume that it won't get worse.

Thanks for the response, Pat! I'll stick with this rpavlis water for a while, might test out potassium bicarbonate to see if I prefer the taste. I might also experiment with spiking the rpavlis water with epsom salt to see if I can achieve a balance of improved taste and non-scaling potential.

Jason