Why the advice not to descale a double boiler?

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#1: Post by Castillo2001 »

So the more videos and articles I read it feels like a lot of vendors and manufacturers are not recommending descaling double boilers. But they aren't saying that about single boilers or HX machines. The only reason I keep hearing is that the double boiler is so much more complicated that if a large piece of scale breaks off it could severely block or damage the machine. But after looking at diagrams and multiple videos of machines cut in half, how is the double boiler so much more complicated? It seems like yes there are a few more copper lines but nothing that makes it impossible to disassemble and clean, to me the HX looks like it could be harder to work on since I don't see a way to easily get into the heat exchange tube. Is this just a fear of manufacturers that people are getting less handy and will end up harming the machines so they are trying to avoid the "you told me to do it, so now you're responsible for fixing my mistake" situation? Or am I missing something?

I am completely behind the idea of preventing scale is better than cleaning scale, but nothing is perfect and after a certain amount of time there is a chance of scale even with the best of water. So wouldn't a mild descale on a yearly or bi-yearly basis be a relatively good form of maintenance.


#2: Post by Smo »

Copper parts are destroyed by acids.

Castillo2001 (original poster)

#3: Post by Castillo2001 (original poster) »

Okay, that is a reason to not descale any espresso machines. But doesn't explain why many are saying don't descale specifically double boilers.

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BaristaBoy E61

#4: Post by BaristaBoy E61 »

My personal experience has been that I descaled our double boiler machine at least twice with no problems and a good result. On the third or forth descaling problems did develop - but not immediately, although shortly there after.

In our case the machine that is direct plumbed and drained developed a leak while I believe it was still 'ON' but not in use at that moment. Fortunately both my wife and I were there at the exact moment when my wife notice that the machine was leaking and flooding our counter.

We were able to stop the leak by turning off the ¼-turn ball valve. It was fast and furious. Had we not been there there is no doubt that we would have had a lot of damage and perhaps an insurance claim.

The problem turned out to be a piece of scale lodging inside a solenoid valve and interfering with steam boiler filling. So yes you can have serious problems - the least of which might be your espresso machine!

I repaired all the problems and there were several issues. When choosing an espresso machine, the more solenoid valves, the greater the chances of problems after descaling. The same goes for check valves and perhaps certain other components too.

Start off with good quality water - it's as important as the espresso machine or grinder you choose and should be part of your purchasing budget.

If you direct plumb you should also direct drain and have a ¼-turn ball valve right at your espresso machine and a leak detector with automatic water cut-off incase a leak develops while unattended.

A proper mixture and concentration of citric acid will not destroy your machine or its copper boilers, piping or other components.

Think water - good non-scaling water even before you're thinking about coffee beans!

"You didn't buy an Espresso Machine - You bought a Chemistry Set!"
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#5: Post by Smo »

Regular cleaning of my Gaggia, after three years, ruined the copper pipe.


#6: Post by Amberale »

I descaled a Gaggia Classic 2-3 times a year with citric acid for TWENTY YEARS with no degradation of the copper pipes.
I think the main complication with double boilers is filling both boilers with your descaler and fully flushing both boilers afterwards.
It seems both are best done manually with the boilers disconnected and opened and syringes used for the descaler.
I'll find out next year when my Bianca is out of warrantee and I get around to it.
I use rainwater and a Bestmin filter so I'll pop an inspection camera in first to see if it is necessary.

Castillo2001 (original poster)

#7: Post by Castillo2001 (original poster) »

I wont be plumbing in, but I have good water filtration to fill the reservoir. I was just trying to wrap my head around why a very spaced out descale to ensure there is no build up is a bad thing. Maybe I will just throw in a BWT in reservoir anti scale filter for added insurance and piece of mind. I am close to purchasing my first serious espresso machine and as Barista Boy said above, I am thinking water before I even get to the beans.

Edit: Or should I go with my filtered water and pull the mushroom every couple of months to see if there are any signs of scale and then put the BWT filter in while also re-evaluating my filtration system if at any point if I do see scale?


#8: Post by Amberale replying to Castillo2001 »

I had my home rainwater tested by a commercial water specialist before fitting a personalised filtration system.
Our water was low in solids but unusually high acidity, possibly due to a neighbouring mineral processing plant.

My thinking was like yours, why not cut maintenance issues in the bud when installing an expensive new machine.

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#9: Post by slybarman »

I descaled my prior HX machine once a year for 8 years or so. So far I descaled my double boiler Bianca once per the manufacturers instructions. No issues with either machine.


#10: Post by Amberale »

Smo wrote:Regular cleaning of my Gaggia, after three years, ruined the copper pipe.
Hey Smo.
What Gaggia did you have and do you know what caused the damage to the copper pipes?
My Classic only had one copper pipe, from the steam valve to the steam wand. :)