homeburrero wrote:A pH of 5 or 6 is expected for any highly pure water that is at equilibrium with atmospheric CO2. The acidity is from dissolved CO2 and water reacting to form carbonic acid (CO2 + H2O ⇋ H2CO3 ). Since there is nothing in the water to buffer that acidity, it's very hard to reliably measure the pH of purified water. Once you add even a tiny bit of bicarbonate the pH comes up to neutral and is easier to reliably measure.

First post on HB...only 11 weeks into real espresso brewing and the "HB newbie espresso" videos were an amazing resource of information! THANK YOU!

If I mix ZeroWater with tap water, does the ZeroWater's pH instantly increase to 7 (instead of 5-6) for that portion of the blend when thinking about the final blend pH? Is there a method to lock-in the low pH, without impacting extraction? I was hoping to mix 1/3 ZeroWater (assuming a pH 6) with a tap water pH of 7.63 to get a final pH of 7.1 . I was trying this based on Seven Miles finding that vanillin (vanilla/caramel/malt flavor) had minimum extraction concentration around pH 7.7 so it was best to get away from a pH of 7.7 for espresso extraction (https://www.sevenmiles.com.au/editorial ... /#conclude).

My ZeroWater pitcher arrives tomorrow and a was planning to mix 1/3 ZeroWater with 2/3 Brita Longlast filtered tap water. I confirmed the Longlast has no impact on my tap water's GH of 125 ppm and KH of 89 ppm. The Longlast is just a very fine filter, without any ion exchange. Mixing in the 1/3 ZeroWater will hopefully getting me around a GH of 85 ppm, KH of 60.5 ppm, and right within the "Water for Coffee" ideal zone. Those would be the specifications I can test.

Based on the city's tap water reports, I expect the blend to have a Calcium Hardness of ~66 ppm, Magnesium of ~4 ppm, and Calcium of ~31ppm. Hoffmann's video (http://www.youtube.com/watch?v=jfElZfrmlRs) had a target Calcium range of 30-50 ppm and I believe a Magnesium target of 1-2 (30/50) ppm. But I could have misunderstood that.

All right, y'all have got me considering buying more coffee-related gear. For years I was on San Francisco PUC / Hetch Hetchy water which is generally good, filtered by a 5-stage, under-sink system. Regrettably, Charlie, the water guru who selected filters for the under-sink system, is no longer with us, but as I recall, it manages chloramine and most "contaminants", but I don't recall if it had any specific intent on reducing mineral content. I do recall Charlie saying that he didn't want to strip the water of everything and make it flavorless. In a new location now, while we still "SFPUC" water much of the year, there are also periods when it is locally sourced ("Bear Gulch" or "Surface Water" in the report)

While the SFPUC water is relatively soft (47 ppm 2019 average) the local source runs around 130 ppm average.

Based on the assumption that dropping the natural hardness and replacing it with a controlled amount of "non-scaling" minerals / buffer is a good thing. I'm looking at the ZeroWater for home use for espresso and potentially pour-over.

How fast is the 10-cup unit in producing 2 liters of water?

Is the TDS meter good for much more than grossly determining that the filter needs replacement? Is there a thread that discusses modestly priced water-monitoring equipment that I haven't found?

Arch wrote:If I mix ZeroWater with tap water, does the ZeroWater's pH instantly increase to 7 (instead of 5-6) for that portion of the blend when thinking about the final blend pH? Is there a method to lock-in the low pH, without impacting extraction? I was hoping to mix 1/3 ZeroWater (assuming a pH 6) with a tap water pH of 7.63 to get a final pH of 7.1 . I was trying this based on Seven Miles finding that vanillin (vanilla/caramel/malt flavor) had minimum extraction concentration around pH 7.7 so it was best to get away from a pH of 7.7 for espresso extraction (https://www.sevenmiles.com.au/editorial ... /#conclude).

Personally, I wouldn't pay much attention to pH. It can be fickle, dependent on dissolved CO2, and hard to measure. You can raise it by adding bicarbonate, or by adding magnesium oxide, or drop it by adding some strong acid, or by spritzing the water with a CO2 spritzer, but hard to say if the added salt or the dissolved CO2 might unpredictably affect the brew. Best in my opinion to just focus on alkalinity, which is a better measure and is related to pH. (If studying acidity in the brew, you would do best to use titratable acidity rather than pH.)

In natural water, an alkalinity of 20 mg/L as CaCO3 would have a pH in the 7.7 ballpark (after equilibrating to atmospheric CO2 and at 25 C). if for some reason you want to get away from that I'd say go with higher alkalinity (SCA recommends 40 mg/l or more.) And unlike pH, you can calculate alkalinity using a simple weighted average of your water mix, i.e. if you use 1/3rd zerowater with 2/3 tap water you will drop your alkalinity from 89 ppm to around 59 ppm. ( 89 * 2/3 = 59.3)

That sevenmiles article was interesting but deficient in describing their methods and results. I never could find a scientific paper on that study. There's some discussion of it here: The Science of Perfect Water for Coffee - Seven Miles Coffee, UNSW .

Arch wrote:I confirmed the Longlast has no impact on my tap water's GH of 125 ppm and KH of 89 ppm. The Longlast is just a very fine filter, without any ion exchange.

Good to know! It makes sense, because they say that copper and zinc is not reduced by the Longlast, but nowhere in their product lit do they explicitly say much about ion exchange resins. I asked Brita in a carefully worded query and got only a robotic reply about availability of their bleach product (Brita US is owned by Clorox.) It used to be hard to find a simple charcoal pitcher filter after Pur added WAC resins to their product. The Brita Longlast looks like it may be a winner here for folks that don't want to drop alkalinity and acidify their coffee water.

Edit addition: I persisted and got a better reply from Brita (Julian, at Clorox Customer Care) that said: "Our standard pitcher filters use coconut-based activated carbon with ion exchange resin in a BPA-free housing to reduce chlorine taste and odor, zinc, etc and our Long-last filters do not use Ion exchange resin."

Jeff wrote:How fast is the 10-cup unit in producing 2 liters of water?

Ballpark of 15 minutes. (I just ran 1 liter thru mine and it took 7 minutes.)

Jeff wrote:Is the TDS meter good for much more than grossly determining that the filter needs replacement?

It's good for telling you if the filter is depleted, but if you're up for a little geeky analysis can be used for more than that when you have a known water. In your particular case If you have pure surface water, which has a reported concuctivity of 430 uS/cm, it would read about 215 ppm if measured at 25C with the zerowater TDS meter. If you have pure SFPUC water, at the average conductivity of 158 uS/cm, it would read about 80 ppm. Note that in both cases your TDS meter is indicating a ppm number that is about 2x the water's total hardness and alkalinity (in CaCO3 equivalents). So as a rough guide you can do a zerowater mix that gives you 80 - 100 ppm on the TDS meter to get water with an acceptable alkalinity (Note that this trick applies to these particular water sources - not necessarily applicable to other waters.)

At that level your calcium hardness should be low enough that you'd see little or no scale.

Jeff wrote:Is there a thread that discusses modestly priced water-monitoring equipment that I haven't found?

Here's a very concise set of links: Making the change from Volvic to home RO water.

You want to measure hardness and alkalinity (GH and KH) as a minimum, and a titration kit is best for that. The API fishcare kit is very inexpensive and easy to use. For your waters, you can calculate from the report that your calcium hardness is roughly 65% - 75% of your total hardness, so you don't need to directly measure your calcium. Your chloride in the surface water is a tad high, at 26 mg/L, but if you are diluting that would not be a concern so you don't need a chloride kit. A pH meter is more trouble than it's worth, in my opinion. Your zerowater TDS meter is good enough - it is an NaCl calibrated meter, and if you are careful to measure at 25C you can double the PPM number to get the conductivity in microSiemen (or micromho) per centimeter. That's what it is actually measuring.

Thank you Pat! I greatly appreciate your help!

FYI: I just posted (Water for Coffee v2) some links to Water for Coffee v2 videos and slides that I just found and are great resources.

The filter rate is a lot faster than I would have expected. A bit under10 min per liter becomes an "on demand" thing, rather than keeping it in the fridge all the time.

What size is a good one for producing a bit under 2 liters per "session"? I generally dump and fill the reservoir entirely and this will eventually be used with a DE1, which I believe has just under a 2-liter capacity.

I'd like to keep the counter/cabinet space to a reasonable minimum for yet another piece of coffee paraphernalia, as well as not having an unwieldy pitcher to pour from, or require both the filter and a holding pitcher if too small.

I've read on an Amazon review that the "10-cup" unit only holds a bit over 6 cups, due to the filter's volume. If that's the case, then it seems I'd need very roughly 8 cups + 4 cups to hold 2 liters of usable water. Is that consistent with H-B experience?

Moka 1 Cup in Post #18 looks like he's got the "11-cup" unit and four fills for a gallon suggests a quart/liter capacity to the inlet reservoir.

Jeff wrote:I've read on an Amazon review that the "10-cup" unit only holds a bit over 6 cups, due to the filter's volume. If that's the case, then it seems I'd need very roughly 8 cups + 4 cups to hold 2 liters of usable water. Is that consistent with H-B experience?

My '10 cup' holds over 2 liters, but the top fill chamber only holds about 1.5 liter, so I just fill, wait, refill to get a full jug. Works nicely with my machine's 2.9 L reservoir. I see they also show slightly larger '11 cup' and '12 cup' that look very similar but currently are out of stock at zerowater.com (https://zerowater.com/products-pitchers).

I found that, at least right now (Thanksgiving week, November, 2020), ZeroWater offers coupons for $10 off any pitcher or dispenser available from the ZeroWater site by clicking on the link, email not required. The coupons I have expire at the end of 2022. It appears to be in-store purchases only, as I don't know that the typical online houses accept manufacturer's coupons.

Bed Bath & Beyond carries several models in store and often has 20% off or better available, making the combination attractive compared to online offers.

See also Black Friday 2020 if reading this on or before November 28, 2020.