Accurate Water Testing Kits
JHCCoffee I think you are barking up the wrong tree.
The 28 TDS (which - as I said above - I suspect are the upper limit of the RO provider’s process, not what you actually get) is largely irrelevant. The tap water analysis is completely irrelevant - you are not using it, and there is no way to predict what (if any) of those dissolved solids is going/not going to be filtered by the RO process.
The problem is that - whether with TWW’s old formulation or my guess at the new one (which I think is a fairly reasonable guess) - that water will scale because of the addition of the TWW formulation, even if you were to add it to pure water.
Whatever is left in the RO water (the ‘28 ppm’ or whatever they really are) will not make things better; it may make them a little worse if there is some residual alkalinity and/or Ca/Mg.
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Got it! Thanks CoyoteOldMan!
So, I need to find a better water recipe. I can/will scan the water recipe section.
At the risk of asking for repeat ideas (sorry!), what, in your view, is the best formula (specific recipe)? FYI, I do like the mouthfeel of higher TDS water, as long as it extracts well and does not scale.
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JHCCoffee It depends on what you want to do… “high TDS” is a bit vague - you could get very high TDS and no scaling by adding say 40,000 mg/l of NaCl. I doubt you’d like coffee brewed with sea water.
Assuming you like water containing ‘general hardness’ (i.e. Ca and Mg ions, which are said to improve the taste of coffee), then avoiding scaling and corrosion is not easy at values of GH and KH that are generally used for brewing coffee. You need to choose your poison.
If you are OK without Ca and/or Mg, then adding 68 - 136 mg/l of NaHCO3 or 80 - 160 mg/l of KHCO3 (‘R Pavlis’ recipe) will provide 40 - 80 mg/l of alkalinity with no scaling, using very cheap chemicals that you can easily find.
My suggestion would be to try with the Pavlis / bicarbonate recipe for a couple of weeks, and seeing if you like the result in the coffee. If so, you are set - $5 of bicarbonate will last you a lifetime.
If you feel experimental, you could try a recipe with 197 mg/l of MgSO4 · 7 H2O (Epsom salts) and 116 mg/l of Ca citrate - this will give you something similar to the total (Mg + Ca) amount and the same KH and GH values as the TWW recipe, but without carbonates involved, so far less risk of scaling. Does it taste good? Does it scale? I don’t know, as I’ve never used it. I will make a bit of concentrate next time I need to do so (couple of weeks) and experiment with its taste. If you can wait… in the meantime try the Pavlis recipe.
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JHCCoffee should I just bite the bullet and buy an RO system? If so, would I end up with a much lower TDS than 28 ppm? What TDS should I except?
The second and third questions are much easier to answer than the first one. Yes, you would expect to end up with <10 ppm TDS with a decent and well-serviced domestic RO system, probably around 1-2 ppm of dissolved minerals.
The interesting question - and part of the answer to the first one - is whether the RO water you are buying actually contains 28 ppm TDS. I doubt it - I genuinely think this is the most you could ever get, and therefore what they tell you, to avoid getting into trouble for false advertising/misdescription/breach of contract/what-have-you-in-Canadian-law.
Even assuming that it is 28ppm (of undesirable stuff), the question is the cost of the RO system vs. alternatives (e.g. ZeroWater-type filters) considering your consumption. If you are only using RO/DI water for coffee, a Zero jug is likely to be cheaper and has no installation costs vs. a domestic RO system.
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.
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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…
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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.
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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.
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
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Has anyone had good luck with the NT Labs KH/GH test kit version which is around £6.99 from Pro Shrimp?