Not so long ago I posted an entry to the effect that I thought reverse osmosis (RO) systems were in no way a prerequisite to top flight espresso, and indeed the move towards them was evidence of the latest method by which to squeeze ever more out of the customer
Fairly soon after that I was taken to task by a LONDINIUM I owner in London, where we have fairly hard water by anyone’s standards I think
Anyway, long story short, he brought to my attention that the cost of RO systems has fallen considerably recently, to the extent that if you have water as hard as we have in London that it may actually be less expensive over time to run an RO system instead of a hydrogen ion replacement filter based softening system that we have used to date
This was all news to me, so I really did get schooled
Anyway, fast forward to today and we took the plunge with these guys –
http://www.detox.co.uk/shop/water-filters/reverse-osmosis/ro103-tds-uv-reverse-osmosis-895721.html
If you add a request when you place your order online that you don’t require the UV add on (which i personally think is a solution looking for a problem) they will take another GBP40 off the price
don’t forget that straight RO water is too soft for making decent espresso so you will also need to buy the mineral cartridge to bring the water closer to pH = 7 & raise the total hardness (TH) (magnesium & calcium carbonate combined) up to at least 50mg/L I’m guessing;
Volvic has a TH of about 85mg/L & might be thought of as the upper limit before you hit scale issues in an espresso machine, especially as the L1 runs at 1.3 bar (precipitation increases with boiler temperature/pressure)
Isklar, the bottled water from Norway has a total dissolved solids (TDS, not to be confused with TD which is just calcium & magnesium carbonate) value of about 32mg/L from memory (TD not stated but will be less as it is a subset of TDS) and gives you an espresso that is too bright and brassy, in my view at least
So we’ve no idea how it will fly, but we’re happy to be your R&D facility, especially if you are considering a plumbed in LONDINIUM I but are pondering how to keep the limescale out.
We’ve absolutely no doubt that the system we have ordered will keep the scale out, its just where the mineral cartridge takes the exact composition of the water back to as this is obviously a function of the water you start with, so its a bit of an adventure
Anyway, it will be fun trying something new. Our plan is to hook the LIII up to it when it arrives & to use a ‘T’ connector to add in a faucet which we can use to draw off water to fill up our tank fed L1 demonstrator machine and compare the results with the softener cartridge that the L1 tank version comes supplied with, and also with Volvic. Between the 3 waters we should be able to triangulate some kind of conclusion
The RO system we have ordered comes with an on-board TDS meter so you can see when the cartridges need replacing as the TDS value rises
We’ll post again when we get it up & running and you are welcome to come and have a look