Thanks again all! I did not expect the water is much more complicated than coffee. I have a bit more understanding on the water now.

So, I think my workflow should be:

Hard water > water softener > softened water > zerowater > prepare mineral concentrate and add to the water > use the mineralised water within 3 days (While keep some water in the zerowater between use (btw do you use this water?))

Re mineral:

Option 1: make it simple

  • KHCO3 (potassium bicarbonate) - 80 mg/l

Option 2: for best taste esp for dark roast

  • MgSO4 · 7 H2O (Epsom salts) - 148 mg/l

  • KHCO3 (potassium bicarbonate) - 80 mg/l

  • NaCl (table salt) - 25 mg/l

For both options, there is no scaling issue but need to replace all water in the boiler from time to time when the mineral concentration built up. May I ask what should be the interval here? Say every month?

Also, before I get a lever machine, for Robot, I plan to use zerowater after I finished the volvic I stock up. As there is not boiler in Robot (no scaling issue), should i add the following for taste enhancing?

  • MgSO4 · 7 H2O (Epsom salts) - 148 mg/l

  • NaCl (table salt) - 25 mg/l

    Knluk Option 1: make it simple

    Option 3, keep it very simple:

    • 80mg/L or 100mg/L (I use the latter, my tastebuds cannot taste the difference)
    • Drain the steam (aka service) boiler every 2 months. When you do, keep the drained water. Let it cool down to room temperature and measure the TDS. Adjust the interval accordingly.

      also worth noting, potassium and sodiums will give different tds readings i believe

      Decent De1pro v1.45 - Niche Duo - Niche Zero - Decent is the best machine ever made -

      Knluk So, I think my workflow should be:

      Hard water > water softener > softened water > zerowater > prepare mineral concentrate and add to the water > use the mineralised water within 3 days (While keep some water in the zerowater between use (btw do you use this water?))

      If you are planning to use a Zero jug, there is no benefit in softening the water before de-ionising it. Unlike an RO membrane, the resin won’t ‘care’ whether it captures a sodium or a calcium atom.

      Yes, I would use the water from the jug, if you keep cycling through it every couple of days. Not if it’s been sitting there for a week!

      Knluk As there is not boiler in Robot (no scaling issue), should i add the following for taste enhancing?

      Water alkalinity plays an important role in taste, so I would add the bicarbonate in the Robot as well.

            CoyoteOldMan there is no benefit in softening the water before de-ionising it.

            No difference for the filter life too?

            I have this 3M filter too but forgot the last time we changed the filter :(((

                Knluk No difference for the filter life too?

                Nope. At least, not if your softener is a typical ion-exchange softener.

                  Please 🙏 help to confirm the following is okay🙏🙏🙏

                  Epsom salt

                  potassium bicarbonate

                  Table salt: (is Himalayan salt okay)

                  Epsom salt and bicarb - perfectly fine. Himalayan salt is also probably fine (it contains a bit of iron, hence the pink colouring, but so little that I don’t think it will affect the taste of anything), but it’s flipping expensive.

                  https://www.sainsburys.co.uk/gol-ui/product/salt-pepper/sainsburys-cooking-salt--polybag-15kg <– this is £1/kg
                  https://www.sainsburys.co.uk/gol-ui/product/bigger-packs-208331-44/fudco-himalayan-pink-salt-500g <– this is £6.30/kg

                    OK so the need to use the water within 3 days is completely new to me. I’ve been storing remineralised Zerowater for my Minima for up to a few weeks at a time before using it in my Minima. I take it this is a bad idea? I would have thought it would be fine since it is all being boiled via the brew - boiler and steam boiler?

                      No salt. Avoid chloride. If you want sodium but want to keep it at scaa recommended 10mg/l use both Potassium and Sodium bicarb to get your alkalinity to 40mg/l - you can go higher or lower with alkalinity if you want but 40 is a good start. No need for hardness, but if you really want to try it and think it makes enough of a different to complicate maintenance do what you want…you have a robot to test on to make it easier. Magnesium isn’t any better than Calcium for scaling.

                        dutchy101 If you aren’t getting smells or colours in the stored water, it’s probably OK. The only way to know is to do a microbiological exam, as presence of bacteria/algae/protists would be the issue. I don’t think “3 days” is a hard limit…

                            Rob1 hi Rob, good to have your input. As mentioned above, I am hopeless for chemistry. But would love to hear your water recipe? I will try on my Robot but the main goal is optimzing the performance and minimising scaling on a boiler machine.

                            • Rob1 replied to this.

                                CoyoteOldMan

                                I’ve been doing this now since February and haven’t died yet, so hopefully all is OK. I have a Skuma RO unit coming in October, when I will be changing how I do things.

                                  Every time a water discussion comes up on here, I feel like I go straight back to square 1 in terms of my understanding of things - lol. Perhaps I might shift to a system of only making up just 1 × 5 litre batch of water at a time until the Skuma arrives as opposed to the 2 × 5I have been making over the last 6 months.

                                  The water is certainly not discolouring, nor does it smell so hopefully it has all been OK so far.

                                  @Cuprajake - how long do you tend to make up and use your concentrate for?

                                    PROB LONGER THAN I SHOULD LOL

                                    Decent De1pro v1.45 - Niche Duo - Niche Zero - Decent is the best machine ever made -

                                    i make a 400ml concentrate, then i make up 8l of ro water at a time, this is stored under the sink in the dark, usually about 2 weeks is for use

                                    Decent De1pro v1.45 - Niche Duo - Niche Zero - Decent is the best machine ever made -

                                    dutchy101 FWIW, I make 400 ml of concentrate, kept in the fridge in a screw-top jar (ex ice-cream jar). It lasts me ~1 month.

                                        Thanks. In terms of an immediate change, I think I’m going to move down to making just one 5l batch using the Zero water at a time until the RO unit arrives. I might move to a concentrate at that stage.

                                        I probably also need to find some better bottles for storing water than re-using old Ashbeck bottles.