Would someone more knowledgable with coffee water assist in analyzing the results of a lot of testing I've recently performed? I'm trying to find the best solution for brew coffee only - no espresso.

General info:

- Whole house, salt based, water softener (not easy to plumb anything presoftener).
- At sink, we have a RO system (Waterdrop G3) that I can use with no remineralizer cartridge or I can add one (see testing with and without).

Pure RO: hardness = 0, PH = 7.0, Alkalinity - 30 , TDS = 41
RO w/ Waterdrop Remineralizer: hardness = 2, PH = 7.8, Alkalinity - 50, TDS = 49
Sink (softened only, no RO): hardness = 0, PH = 7.4, Alkalinity - 130 , TDS = 205

Pre-softener (I think there is a way to determine sodium from this?): hardness = 9, PH = 8.3, Alkalinity - 110 , TDS = 200

Any suggestions on optimum brew water with any of the above or combinations? The Waterdrop remineralizer doesn't seem to do much (hardly a difference in numbers above). If a remineralization filter is suggested, would a different brand do any better? I could also do a mixing valve with pre RO and post RO (with or without remineralization) - any suggestions on mixing valve if this is suggested?

This all started after a couple brews with RO/remineralizer that weren't great. The only difference between previous delicious cups was the water (previously using distilled with Third Wave mix).

The ideal solution is a plumbed water source - I don't want to mess with mixing anything anymore.

Any help is greatly appreciated.

The units here aren't clear to me. For example:

zero610 wrote:Pre-softener (I think there is a way to determine sodium from this?): hardness = 9, PH = 8.3, Alkalinity - 110 , TDS = 200

It that hardness measure 9 ppm as CaCO3? or 9 gpg? or 9 °dGH? And is the alkalinity 110 ppm as CaCO3?

You can determine the sodium from the softening. For every ppm as CaCO3 of hardness that your conventional sodium softener removes from your water you expect an added 0.46 ppm of sodium ion.

zero610 wrote:I could also do a mixing valve with pre RO and post RO (with or without remineralization) - any suggestions on mixing valve if this is suggested?

If you have an RO with a mixing valve, and you're just doing brew coffee, then just tweak the blending valve to get the taste that you like. With espresso you have to concern yourself about getting the RO blend right so that you avoid scale and corrosivity issues, but for a kettle or a simple coffee brewer, scale and corrosivity is not the major issue that it is with an espresso machine.



P.S.
For those who are interested in the calculation...
molar mass of CaCO3 = 100.1 g/mol
molar mass of Na⁺ = 23 g/mol
Each Ca²⁺ is replaced by two Na⁺
( 2 * 23) / 100.1 = 0.46

homeburrero wrote:The units here aren't clear to me. For example:

It that hardness measure 9 ppm as CaCO3? or 9 gpg? or 9 °dGH? And is the alkalinity 110 ppm as CaCO3?

You can determine the sodium from the softening. For every ppm as CaCO3 of hardness that your conventional sodium softener removes from your water you expect an added 0.46 ppm of sodium ion.



If you have an RO with a mixing valve, and you're just doing brew coffee, then just tweak the blending valve to get the taste that you like. With espresso you have to concern yourself about getting the RO blend right so that you avoid scale and corrosivity issues, but for a kettle or a simple coffee brewer, scale and corrosivity is not the major issue that it is with an espresso machine.



P.S.
For those who are interested in the calculation...
molar mass of CaCO3 = 100.1 g/mol
molar mass of Na⁺ = 23 g/mol
Each Ca²⁺ is replaced by two Na⁺
( 2 * 23) / 100.1 = 0.46

Yup - units might help. Sorry about that.

Hardness is grains per gallon.
Alkalinity is ppm as calcium carbonate.

My RO doesn't already have a mixing valve. I'd need to add something if the suggestion is mixing RO and tap (softened) water. Easier, I'm sure though, is a better/different inline remineralization filter, geared more towards coffee (if that exists?).

I'm estimating the sodium around 88mg/l for the tap (soft water). Am I doing that right?

zero610 wrote:is a better/different inline remineralization filter, geared more towards coffee (if that exists?).

If you're getting a 20 - 40 ppm as CaCO3 (~ 2 gpg) bump in hardness and alkalinity out of that filter I'd say that's about as much as you expect to get out of any calcite filter. You get more or less depending on contact time and pH of the water going through the filter. Probably not much to be gained by trying other remineralizers. The ones that contain some magnesium oxide (Corosex™ is one example) should give you a little more but probably not enough to switch. They have a downside in that they can be prone to overcorrect, especially after water sits idle in the filter. Simple calcite is better if you want predictable remineralization and pH.

The numbers you reported out of that RO + Waterdrop don't look so bad. For brewed coffee you could experiment with correcting with some mineral additions -- Epsom salt or calcium chloride to increase hardness, sodium bicarbonate or potassium bicarbonate to increase alkalinity, although you probably don't need to increase alkalinity for your brewed coffee. Perhaps even consider using Lotus Drops to experiment and find your preferences.

zero610 wrote:I'm estimating the sodium around 88mg/l for the tap (soft water). Am I doing that right?

I think so. Your softener's reduction from 9 gpg to 0 gpg is a 154 ppm as CaCO3 reduction, and 154 * 0.46 = 70.8. So your softener added about 70 ppm of sodium ion to your water. We don't know how much sodium was already there, so a total of 80 - 100 ppm is a reasonable guess for your final softened water.


P.S.
some handy factors:
1 gpg = 17.1 ppm as CaCO3
1 °dH = 17.8 ppm as CaCO3
1 °fH = 10 ppm as CaCO3
1 mEq/L = 50 ppm as CaCO3
1 ppm calcium ion = 2.5 ppm as CaCO3
1 ppm magnesium ion = 4.12 ppm as CaCO3

homeburrero wrote:
The numbers you reported out of that RO + Waterdrop don't look so bad. For brewed coffee you could experiment with correcting with some mineral additions -- Epsom salt or calcium chloride to increase hardness, sodium bicarbonate or potassium bicarbonate to increase alkalinity, although you probably don't need to increase alkalinity for your brewed coffee. Perhaps even consider using Lotus Drops to experiment and find your preferences.

Thanks for all the info. Are there any remineralization filters you know of geared towards coffee, rather than just drinking/mineral water?

zero610 wrote:Are there any remineralization filters you know of geared towards coffee, rather than just drinking/mineral water?

I think any simple calcite filter is as good as any for this purpose. Looking through the Pentair product line, their mineral addition filters for coffee/espresso RO units are all Ilma 6.14, which is a simple calcite filter. I suspect any other crushed marble or calcite filter is just as good. If you don't have a carbon and particulates finishing filter then it may be wise to add one, or use a finishing filter that has that in addition to calcite. Main purpose of that is to remove off tastes that come from the accumulator tank.


I should mention that Cirqua / GCWater made a tricky A B formulator system that can inject hardness and/or bicarbonate solutions into the water that could be used along with blending to hit specific hardness and alkalinity targets for coffee shops that are finicky about that. Very pricy, reportedly hard to maintain, and I'm not sure if it's even still available. See https://www.globalcustomizedwater.com/p ... nex-ro-900. GCWater also sells a conventional remin cartridge, and that one is simple calcite with activated carbon.

With the help of CarefreeBuzzBuzz, got my water setup all squared away. After trying 3 different remineralization filters, I ended up going with stock RO and mixing my own water. Thanks to everyone for all the help.