Some time back I lived near Durham1For the sake of clarity, that’s just plain “Durham”, the ancient pilgrimage destination, rather than the Durham which always seems to have “North Carolina” appended to the name. where the water is blissfully soft. Five years of sparkly clean kettle and coffee machine that just don’t scale up! Since moving to a harder water area, I have often wanted to recapture those halcyon days. And now I think I may have…
I’ll spare you the long sob story about fruitless googling for simple effective answers to scale and jump to the solution I am now trialing: citric acid.
We’ve been using citric acid as a descaler for a while. But I started wondering whether I could use citric acid to prevent the build-up of scale in the first place. With a bit of experimenting, I have found that even a tiny concentration of citric acid in the water when I fill the kettle completely eliminates scale build-up in the kettle.
Presumably the coffee machine gets the same benefit, but it’s harder to tell whether there is scale inside the boiler as it is sealed. However, time will tell. If there is still scale build-up then sooner or later the steam valve or the solenoid will become blocked. If that doesn’t happen for a few months, I’ll know I’m home and dry.
So, two questions: 1. How much citric acid is needed? and 2. We are now consuming citric acid in our tea, coffee and anything else that involves boiled water. What does it taste like?
Our water is medium hard. I find the kettle normally develops a visible scale build-up in a period of weeks and we tend to descale every month or two. With this water I have found that as little as 0.1ml per liter keeps the kettle shiny2In both the dictionary sense and the Firefly sense.. Perhaps a lower concentration would do it, but it’s difficult to accurately make such lower concentrations without having to prepare far more water than I need to fill the kettle. (Especially considering I try only to boil the water I need rather than boil a whole kettle just for one cup of tea.) So that’s what I am going with.
How does it taste? We can’t tell the difference at that concentration in either tea or coffee.
I’d be interested to hear others’ experience. Especially if you have very hard water.