Having met the initial requirement that I reliably pull a shot with cafe regularity by sticking with one espresso roast in order to learn about it, learn about my machine (Londinium) and iron out my technique, I was now ready to look into the effect of the brewing water.

The box of Global Customized Water ampoules arrived while I was still settling into a dependable technique. When the time came, I mixed up a gallon (in a glass jug) according to directions. In a few days as the second gallon was going through the pourover tank and the boiler, I came to the conclusion that the quality of the cup was most dependent upon the quality of the infusion cone (I always use and monitor a bottomless PF) and that small variances in technique had a larger effect upon quality than did the GCW.

While this was going on, I mistakenly left some clean Albuquerque tap water in my Americano mug when I poured the first shot glass into it. Somewhat daunted but inquisitive nonetheless, I poured the second shot into the mug and topped up with the hot water from the boiler. This Americano had all of the flavor of my best pulls plus it had a sweetness that had not been present from my machine but had been present in pulls of this roast from other locations. For the past week, I have been enjoying Americanos from this roast by infusing with GCW and topping up with GCW and off-the-boil tap water to result in a 50:50 tap to GCW ratio in the final mug.

I expected that this arrangement was useful only for this situation and that it would not generalize to other blends and techniques.

So I brought some GCW and a 50:50 mixture of GCW and my tap water to Cindy at Prosum Roasters here in Albuquerque. She roasts a great SO Burundi that is wonderfully sweet and nutty and chocolatey - a primal cup of comfort coffee. While most folks use it as an espresso roast, I think the flavors of the roast are best brought out with the clarity of siphon extraction. So what I asked her to do is to brew three cups of Burundi using the siphon, using her commercially conditioned water, the GCW and the GCW:tap mixture.

All three of us (two roasters and myself) agreed that the favors were most distinct and there was an additional sweetness present when the GCW alone was used. Her conditioned shop water gave a close second cup, without quite all of the clarity and none of the sweetness of the first cup, while the addition of the hard tap water muddied the flavor profile and introduced some bitterness into the cup. Note that the tap water was included in the brew process during the siphon run but is not used in brewing using my machine; it is added afterward.

I can draw three conclusions from all of this. Some other responses with other conclusions are possible, as well.
1. Global Customized Water seems to live up to its reputation to clean up and intensify the flavor profile when used to brew roasts provided that other variables that affect brew quality are controlled for.
2. Depending upon what other water is available, each roast and brewing technique may have its best benefit from an unique TDS and pH profile of the brewing water.
3. If the roast, ratios, temperature, grind are in a constant state of variability, changing the brew water may not make a noticeable difference in the quality of the cup.

BT

Reading your post and checking out the GCW website, I have no idea what this service does to the water. What product did you use? What does it do to the water? What's the composition of the water?

Global Customized Water used to be called Cirqua. Their primary line of business, as the web site indicates, is systems for shops that follow R/O units with controlled remineralization. For a while, they were selling kits to allow someone to do the same thing at home, and those were covered in this thread.

Best,
David

It looks like only Seattle Coffee Gear still has these home kits for sale.

That is correct.

@brianl - there are many discussions on the coffee web sites about GCW and the TDS of brewing water in general. It is currently being used by the SCAA as their standard brew water. It will be easy for you to bring yourself au courant on this subject.
BT

Im very up to date on water standards but nothing about their website says what it is. I generally don't accept "it meets the standards" as a reason to use a product.

It probably is added to distilled water. So what does it add? Just bumping up the hardness/TDS tells me nothing about the mineral content.

brianl wrote:Im very up to date on water standards but nothing about their website says what it is. I generally don't accept "it meets the standards" as a reason to use a product.

Neither do I. That is why I will buy a trial amount before considering putting it to routine use. To paraphrase Duke Ellington, "if it tastes good, it is good".

Before I buy a trial amount I will listen to the advice on both sides of the issue from people with more experience than I have.

Number of posts does not make someone more experienced than me; I take into account their equanimity, reasoning and attitude, as well as breadth of knowledge.

Would you proceed any differently?

Regarding GCW, it is a proprietary mixture of calcium chloride, potassium bicarbonate and sodium bicarbonate degisned to closely approximate the SCAA's standards for brew water. Call them what you will, the characterization of brew water has been reported to be a difference that makes a difference to coffee evaluators who are respected for their ability to taste and report upon a drink in a way that a majority of coffee drinkers find beneficial, and with which they agree.

The directions (and I am surprised that they are difficult to find on line) are to add the product to RO or distilled water. In my hands, when added to Zerowater-produced RO water according to directions, GCW produces a batch with TDS 174, GH 125ppm, KH 54 ppm and alkaline pH (>7.6).

Is GCW a racket? In my opinion, yes, in the same way that Coca-Cola is a racket. If I bothered to, I could most likely successfully iterate mixtures to the approximation of CGW at a drastically lower cost. If you have the time, you could do the same.

Here are two reads, one from the coffee viewpoint and one from the drinking water viewpoint on the construction of water:

http://www.jimseven.com/2010/11/28/fear-of-water/
http://www.alcademics.com/2013/02/trans ... cerpt.html

BT

Knowing the exact ingredients would be nice, but if they told you that I think you might be tempted to mix your own. Given that it claims to bring you to SCAA targets, and that it contains CaCl, NaHCO3, and KHCO3 you can sort of guess as to probable contents.

To meet Ca hardness of 68 mg/l (as CaCO3) you would need .68 mmole/l of Ca, which would be 75 mg/l of the CaCl after mixing with the gallon of distilled. That CaCl is providing half of your SCAA target TDS of 150mg/l, and the rest of that TDS would come from a mix of the Sodium and Potassium bicarbonates. Since SCAA has a low target for Sodium (10 mg/l Na+, or 0.45 mmol/l), the NaHCO3 content (after mixing) would need to be about 35 mg/l. You would need a bit more bicarbonate to get the alkalinity up to the 40 mg/l target, so the KHCO3 would do that for you. The pH would be in the high side of 7.0 because you've added bicarbs and no acids, which is good, because otherwise your high chloride from the CaCl might be a corrosion concern.

BuckleyT wrote: In my hands, when added to Zerowater-produced RO water according to directions, GCW produces a batch with TDS 174, GH 125ppm, KH 54 ppm and alkaline pH (>7.6).

Thanks Buckley - good to know. Compared to the SCAA standard, yours does come out with a little higher GH number than I would have expected. The mix may be produce numbers within acceptable limits but not right on target. The high pH as well as having GH and KH slightly on the high side of the target seems good to me. I'd rather descale occasionally than worry about corrosion.

Edit addn: It should be CaCl2 everywhere above instead of CaCl. I did do my calculation using the molecular wt of CaCl2, so the numbers should be OK.

homeburrero wrote:Knowing the exact ingredients would be nice, but if they told you that I think you might be tempted to mix your own. Given that it claims to bring you to SCAA targets, and that it contains CaCl, NaHCO3, and KHCO3 you can sort of guess as to probable contents.

To meet Ca hardness of 68 mg/l (as CaCO3) you would need .68 mmole of Ca, which would be 75 mg/l of the CaCl after mixing with the gallon of distilled. That CaCl is providing half of your SCAA target TDS of 150mg/l, and the rest of that TDS would come from a mix of the Sodium and Potassium bicarbonates. Since SCAA has a low target for Sodium (10 mg/l Na+, or 0.45 mmol/l), the NaHCO3 content (after mixing) would need to be about 35 mg/l. You would need a bit more bicarbonate to get the alkalinity up to the 40 mg/l target, so the KHCO3 would do that for you. The pH would be in the high side of 7.0 because you've added bicarbs and no acids, which is good, because otherwise your high chloride from the CaCl might be a corrosion concern.

I mix distilled and filtered tap water and add back potassium bicarb so it looks like we're getting the same thing (this is for espresso so i'm shooting for GH of 50 and TDS of 100. Chicago tap water is basically perfect after its filtered for brewed coffee with a berkey so no adjustments needed.).

How did you calculate pH? that seems kind of high considering the low kH. The below from Jim's FaQ

Equilibrium Water pH vs Bicarbonate Alkalinity in mg/L CaCo3
pHeq 6.0 6.2 6.4 6.6 6.8 7.0 7.2 7.4 7.6 7.8 8.0
Alkalinity 10 14 19 26 35 48 65 90 123 168 230

I think it's better to have a kH above the standard as alkalinity of 40 would produce water that is slightly corrosive to copper.

brianl wrote:How did you calculate pH? that seems kind of high considering the low kH. The below from Jim's FaQ

I didn't calculate, I think that calculating pH gets a little messy because of the equilibrium reactions with the CO2. I think Jim's pH table is good for natural undoctored waters, may not hold up as well once you start adding chemicals or running through softening systems.** I see Buckley got a high pH relative to his alkalinity. To Buckley - did you shake and aerate the sample real good before testing your water mix? If not, that might have affected your pH and alkalinity numbers a little.

brianl wrote:I think it's better to have a kH above the standard as alkalinity of 40 would produce water that is slightly corrosive to copper.

Agree with that. And the higher pH is good too. I've seen lots of warnings about the corrosive effects of chlorides and sulphates, and there is that CaCl in the mixture.

** [Edit addition] More importantly, That pH table is for the Puckorius equilibrium pH, which is a number designed to work well when doing scaling calculations for boilers. It is not intended to agree with the pH you might observe in an open container at room temperature after equilibration with atmospheric CO2. For that you can use an online calculator - http://www.aqion.onl/show_ph to do the messy calculation for you.