Hi all,

Seven Miles Coffee in Sydney just posted this interesting article about water. I've only given it a quick glance, but it looks as though they reported on the 2+ cations in the familiar CaCO3 eq ppm notation, but didn't report on alkalinity in CaCO3 eq ppm - they did report on pH, though. Looks like someone actually did some chromatography and spectroscopy on actual coffee for a change, which is quite interesting and worth a look. Given that they went to all of that work, I found it a bit disappointing that it was written up as more of a blog post and less of a proper paper that details the actual methodology. I find myself left with questions like what were their extraction parameters and how do they relate to what I'm trying to do.

The article starts off being sceptical about dissolving epsom salts, which gels with our good friend rpavlis' view. However, it is against the background of Sydney tap water, which seems to be in the ca 60ppm CaCO3 equivalent 2+ cation zone. In Melbourne, around me, we're at about half that. I haven't really been thorough in my investigation of adding 2+ cations, but I think I'll revisit it to taste for myself.

In terms of pH, the article generalises that higher pH generally results in more flavour. I think my pH is a scooch over neutral and I do tend to use a little bicarb, but, again, I might have another go and taste for myself.

There's a snippet on this article here at beanscene magazine, which runs the headline that they have conducted a "study" that "shuts down espresso myth", though what myth, exactly, that is, I couldn't really work out from the article. From the article, I guess they are saying that "designer water" is a myth, which seems contradictory to me in that the study seems to stand for the proposition that some water is better than others for espresso brewing, therefore I would have thought that if you fall short of that then some sort of water treatment would be beneficial (maybe water treatment and "designer water" aren't the same thing?). Maybe by "designer water", they mean Beverly Hills 90H2O? The beanscene article gives the additional information, not in the Seven Miles article, that apparently boiler limescale and mineral deposits could cancel out the benefits of hard water, but I couldn't find any more information than that.

The beanscene article goes on to say that Seven Miles will use the research in their education programs, so presumably they have some course or something that they want you to pay for to get more detailed information. Which, I suppose, is fair enough; it's not like this stuff can be done without time or money!

Cheers,
Luca

I agree - looks very interesting. Hope a real scientific publication will be coming out soon - dying to see some statistical analysis, some discussion of experimental methods, and hopefully some alkalinity and titratable acidity numbers in addition to pH.

I see that Adam Carr will be giving a lecture at the SCA Expo in Boston this April

luca wrote:Hi all,
but didn't report on alkalinity in CaCO3 eq ppm - they did report on pH, though.

Between alkalinity and Ph there is a direct relation given water hardness.
One point though they did not state water hardness when they tested pH. I assume though around 70 ppm. So alkalinity around 40ppm for pH 7

lucasd wrote:Between alkalinity and Ph there is a direct relation given water hardness.

There is a relationship between equilibrium pH and alkalinity in water with carbonates*, but once you start adding chemicals or scrubbing or adding CO2 you can get pretty far away from that. My guess is that they may have simply been adding HCl or NaOH to hit their numbers for their pH experiment. It would help to know more.

Likewise with hardness. Most likely they created different levels of hardness by starting with a hard water and diluting that down to get their lower hardness waters. Or possibly used a softener of some sort. It would be good to know which method, and what anions (carbonate, chloride, sulfate) were associated with the hardness cations (e.g., Ca²⁺ and Mg²⁺) .

The results do look interesting - this is the first time I've seen a quantitative chemical analysis that appears to demonstrate a marked increase in extracted compounds like furnaeol due to small amounts of hardness minerals in the incoming water. (To go directly to their graph, see this infographic: https://infogram.com/water-hardness-int ... 3prx71k4xr and select "Fruity").





* Jim Schulman's Insanely Long Water FAQ includes a table and equation for the relationship between alkalinity and Puckorius pHeq, which is the pH that can be used in scale formation estimates.

That Seven Miles article linked the first post needs some editing. Calcium hardness will cause corrosion? Really? He also confuses chloride with chlorine at one point, but what's an electron between friends, right?

I mean that a little tongue and cheek, however, it is sloppy for a phD. From the article:

"THE RESULTS - CHLORIDE
We didn't taste stuff with extreme chloride concentrations. Why? Well, we didn't want to drink chlorine. Nor subject our machines to these extremes. However, we do have recommendations here."

And

THE RESULTS - HARDNESS
Water hardness refers to the magnesium and calcium minerality of water (aka multivalent cation concentration). Hard water has many of these cations, soft water doesn't have many cations.

Why are they important? Well, for coffee, if water is too hard, these cations can crystallize in your boiler and within the pipework, blocking flow and causing corrosion.

He uses "I" and "we" in the first paragraph together without introduction. I'm glad he's inspired to use his knowledge for coffee.