Thanks OldManCoyote!

I actually used a hand TDS meter, and the RO water I bought was 28 ppm. So too high!

Thanks for the tip on the ZeroWater filter. Do you end up with a TDS that is close to your suggested < 10 ppm, using that filter?

I currently have a BWT jug, but I suspect that it is not as effective as Zero Water. Any thoughts on BWT?

Re “higher TDS”, when I was making that Grind Science recipe I enjoyed the body of espresso with the water at 160 TDS to as high as 200 TDS. Not sure what I would do, prefer today now that I know somewhat more.

    JHCCoffee You don’t need to send your RO water to the lab, IMO. Please get a drop kit, measure the GH and KH of your Pure RO water on a sample of 20 ml or 40 ml for each test, multiple 17.9 by number of drops and divide the output by 4 (if 20 ml) or 8 (if 40 ml). As Rob and CoyoteOldMan advised, keep it simple.

      JHCCoffee I actually used a hand TDS meter, and the RO water I bought was 28 ppm. So too high!

      Be careful… readings depend on temperature, the type of ions dissolved, all sorts of stuff… While 28 ppm is relatively high for something coming out of a domestic RO system, it is not a highly mineralised water in general. No matter what the 28 ppm are, it’s quite unlikely to scale in a normal use for coffee making (although if you use it to steam, you will still need to flush the boiler every so often as steam boiler water dissolved minerals will get more and more concentrated).

      JHCCoffee Do you end up with a TDS that is close to your suggested < 10 ppm, using that filter?

      My range goes from 0 to 6 on the ZeroWater TDS meter (nothing special, but at least I checked its calibration, and I know it’s reasonably accurate for 25 - 200 ppm NaCl at 20-25 °C) - then I change filter!

      JHCCoffee Any thoughts on BWT?

      I haven’t used them - so this is what I understood from their website: they don’t provide any real technical indication of what they actually do. I assume you are using one of the ‘softening’ filters, rather than the ‘mineralising’ or ‘alkalizing’ ones.

      “Limescale reduction” means SFA - what % of limescale-generating salts is the filter eliminating or substituting? With what? Probably they contain a ion-exchange resin that replaces Ca and Mg ions with Na ions; what percentage of ions are exchanged in not known, but not 100% (otherwise why would they have two ‘strengths’?). The ZeroWater filter strips all ions, and doesn’t replace them with anything else. The BWT may produce better tasting drinking water, since they are aimed at that; the Zero is aimed at producing water with minimal mineral content for use in steam irons, coffee machines and other applications where de-ionised water is used.

      JHCCoffee I enjoyed the body of espresso with the water at 160 TDS to as high as 200 TDS

      The problem is that “TDS” means nothing (or very little in the context). 160 ppm of kitchen salt does not have the same effect on taste of 160 ppm of potassium bicarbonate or magnesium sulphate - or potassium bicarbonate AND magnesium sulphate. Alkalinity is at least as important a modifier of coffee taste as the amount of Ca or Mg. FWIW, the “R Pavlis” water can be in that range (for a KH of 70-80), and the “sulphate + citrate” recipe I posted above is over 200…

              [

              This is the TWW espresso recipe quoted above if you put it into an imperial gallon of water. TWW want you to put it in a US gallon which is about 20% less water.

              There’s no accounting for the sodium from the TWW sachets as their listed ingredients are Magnesium Sulphate, Calcium Citrate, and Potassium Bicarbonate. It looks like the amounts have been tweaked slightly, maybe they realised they get alkalinity from citrate and sulphate (not calculated) and reduced the bicarbonate by almost 50%.

              It might be worth just using Calcium citrate and Magnesium Sulphate to remineralise some water and then titrate the sample down to a pH of 4.5. Citrate provides alkalinity below this but as it’s acidic I think that’s missing the point when it comes to making coffee and taking care of machines.

              So where the Na and Cl come from in your analysis? Likely the RO water itself. Possibly put through a salt softener before RO giving it high Na and Cl slipping through is normal.

              JHCCoffee I currently have a BWT jug, but I suspect that it is not as effective as Zero Water. Any thoughts on BWT?

              Different tools for different jobs, if you have moderately hard water the BWT Mg2+ filter might make it suitable without further treatment (check with a drop kit). Zerowater will need remineralising.

                Thanks all for your constant advise and support. It’s sincerely appreciated! It’s great that we can just help each other out. No questions are too small, no egos to big to answer them. Everyone is polite, considerate and helpful. I cannot say this about some other home barista related sites I have been on. Thanks again.

                PS

                As a result of my recent TWW water chemistry test and your excellent advise, I’m ceasing use of the TWW powder. And I am ditching my RO water supplier. I’ve ordered a ZeroWater pitcher, a decent quantity PH meter and a Total Hardness water test kit (titration). I’m now reading up on all things water (via BaristaHustle) and will soon be in a position to make decisions on the water recipes I wish to try.

                All good.

                • Rob1 replied to this.

                  JHCCoffee You’ll need an alkalinity test kit too. pH isn’t alkalinity. You can usually buy hardness and alkalinity test kits together.

                    Thanks Rob1.

                    What type of Alkalinity test kit do you use? I’ve seen test strips and dials, a meter by Hanna and I am betting I’ll find a titration kit. The Hanna seems good, but you still have to buy the reagent, so the total cost of that route is getting pricey.

                      I use this

                      JHCCoffee This is a good, relatively inexpensive kit available on Amazon US:

                      Cross-posted with Rob.

                        Has anyone had good luck with the NT Labs KH/GH test kit version which is around £6.99 from Pro Shrimp?

                        • LMSC replied to this.

                          Verion NT Labs KH/GH test kit version

                          Please tell us how you got on !😃