Rob1 Thank you for your replies. Clearly your level of understanding of water is comprehensive. It has made me realise that although I am trying to simplify everything some basic understanding of water chemistry is helpful.
I am never going to have your level of Knowledge but the more I am reading the more the penny is dropping. So this is where I am now in my understanding:
Using and maintaining an espresso machine and keeping reliability to a maximum requires good quality water suitable for the machine. This is based on the initial and unequivocal fact that the quality of water is probably the number 1 factor to minimise short/ long term machine problems.
Starting from that baseline my understanding is that tap water is full of various minerals and that these will differ according to how the water is naturally filtered eg: there may be more chalky mineral salts dissolved into the water as it filters naturally which would make the water harder. Finally water authorities will add/ remove minerals to the water to purify it and/ or improve its perceived quality. The net result will be water that differs from area to area.
From an espresso machine point of view removing these minerals through reverse osmosis or jug filters would at first seem the logical solution. i.e. if we remove calcium and magnesium minerals ( principal causes of limescale formation) then this would be job done? If only it were that simple.
My understanding is that in so doing you are then affecting the PH level of water i.e. the acidity/alkalinity factor. Why does this matter? Well if you make water more acidic ( which is what happens when you remove all minerals) then corrosive factors come in to play. At first I thought Ok that only matters if you have brass boilers. Alas I also realise that although helpful having stainless steel boilers, a cursory look at most espresso machines will identify many brass pieces.
That then brings the fact that adding something back is helpful. Hence where bicarbonate of Soda comes in as it raises PH and hence alkalinity values. There is also a taste factor for some who may feel demineralised water may not taste great eg zero water. Although I wonder if that is going to differ from person to person as surely if you remove all minerals from water then are you not effectively tasting the inside of your mouth?
In conclusion for most a standard RO treatment with a few minerals put back in should do the job, along with some periodic refreshing of the service boiler along with an annual or half yearly check of the mushroom for signs of scaling. Ideally a simple wifi endoscope obtained at low cost from amazon inserted into each boiler would give a clear indication of how effective the quality of your water. something such as:
endoscope
Rob or anyone else am i starting to think along the correct lines or is my understanding still wide of the mark?
