Home-Barista.com

The water forum seems unusually busy lately -- having a hard time keeping up.

Re adding a shot of concentrate with suspended calcim carbonate"

millmountain wrote:Agitation will distribute the particles in suspension, but if the calcium carbonate remains undissolved, surely it isn't helpful?

When I add one shot of it to 3 liters in a gallon jug it dissolves completely. I never get sediment on the bottom of the jug. When adding it directly to the reservoir I do that before putting the machine to bed, so it has overnight for the suspended particles to dissolve fully. Keep in mind this is a fairly low concentration - about 20 mg/L calcium as CaCO3.

millmountain wrote:Wikipedia says the solubility of CaCO3 in water is 13 mg/l at 25°C, and of MgCO3 is 139 mg/l at 25°C and 60 mg/l at 100°C.

It's more complex than that when dissolving in water where it reacts with dissolved CO2 to become calcium bicarbonate, Ca²⁺ + 2HCO₃⁻. At 25C and with water at equilibrium with CO2 in the air, just over 50 mg/L of CaCO3 will fully dissolve in water.

millmountain wrote:I'd rather find a decent source of MgCO3, but after some web-search grinding, Bulk Supplements is the only thing that came up as available. Shipping is pretty steep for me. Maybe none of it matters if the Mg concentrate will just saturate?

I just use just Bulk Supplements MgCO3, which it turns out is actually dypingite - 4MgCO₃ * Mg(OH)₂* 5H₂O. Once dissolved you get magnesium bicarbonate same as you would if you were to use simple magnesium carbonate. (The magnesium hydroxide ends up as magnesium bicarbonate -- Mg(OH)₂ + 2H₂CO₃ → Mg(HCO₃)₂ + 2H₂O .) Molar mass for dypingite is 486 g/mol which is 97g per mole of Mg. For MgCO3 it would be 83g per mole of Mg, so you do need to allow for that for accurate recipe calculations.


I looked at those references and now understand the reason for that odd calculation:

millmountain wrote:I wonder if this isn't the reason for reformulating carbonates and bicarbonates as CaCO3 equivalents with a 0.6 factor.

Those methods assume you have mass measurements for the major ions, Ca, Mg, SO4, Cl, K, Na, but not for the HCO3 ion. They use the factor 0.6 * alkalinity as a way to estimate the mass of the HCO3 ion. When you are making water with just NaHCO3 or KHCO3 you know the mass of the HCO3 ion and don't need to estimate it from the alkalinity.

[To be continued - I clicked submit when I was only halfway thru my response to Mike's last post]

[ picking up where I left off above ... ]

millmountain wrote:The following link is the online resource for reporting of water quality for Prague. The good news is the numbers are published on a monthly basis, the bad news is that it's only in Czech.

As you say, that report lacks alkalinity or bicarbonate numbers, but otherwise it's pretty complete - much better than the usual 'consumer confidence report' we often see from US utilities.

Your chloride is nice and constant, but borderline troubling. It's a judgement call as to whether that's acceptable. It's within La Marzocco but above Synesso guidelines.

Total hardness runs about 150 - 165 mg/L as CaCO3 and calcium hardness works out to 115 - 135 CaCO3 equivalent.. Since the sum of sulfate and chloride ion is only about 0.7 mEq/l higher than the sodium (which is equivalent to about 35 mg/L CaCO3) it's reasonable to assume that the alkalinity might be in the 100 mg/L ballpark. That's easy to test with a KH titration test.

millmountain wrote:So my main question: Since the BWT Bestmax I was considering "drops alkalinity in addition to hardness and may acidify the water, which is not good if you have chloride or sulfate concerns," is there an alternative filter system that would also filter the chlorides and sulphates?

That's a tough call. On a vintage machine or an expensive machine I wanted to keep forever I would not risk it, would go with RO. But if your alkalinity is up around 100 there is advice that a WAC filter like the BWT bestmax might be OK: See /downloads/ ... pdated.pdf where Pentair advises that for stainless steel, WAC softeners are "great for water with bicarbonate levels above 100 & low chloride and sulfate levels less than 80ppm and 150ppm respectively. "

I've left this discussion idle as I've been thinking it over. I want my machine to last as long as possible, and I want total control over the water quality. I don't want to have to keep track of the incoming water quality and efficacy of whatever filter I might have chosen, or worry about chlorides and sulphates. So I went ahead and ordered a distiller and will have to live with the higher energy use. It's not the financial so much as the ecological aspect; we have been using about 2 liters a day in the machine (lots of home office), so the 3 kWh per 4 liters comes to something like an extra average shower per day (assuming 1.5 kWh for a 10-minute shower). At least the use should lessen after travel restrictions are lifted.

I want to pick back up on the idea of adding Mg and Ca to the rpavlis recipe, and would like to experiment with taste testing. Tough with a single machine, since changing the water requires flushing the boiler. This eliminates a side-by-side comparison, but making several coffees with one water before switching could help. I have ideas for my americanos, too, but that can be a separate thread.

Pat, this thread has been immensely helpful to me. Thanks for the heads-up on the chlorides in my first recipe, and for helping me decide on a course of action. I don't know who put you in charge of the water forum, but they should be promoted.

That is one very interesting thread! A few comments on some to the points discussed. Just my humble biased opinion here, I am not a chemist and did not do triangle tests with a trained panel .

Regarding filters:
WAC Filter + re-mineralize does not seem to be a good solution when the water used is hard. I tried with my hard tap water ( KH about 12-13, GH about 16, filtered the water twice through a Brita to get GH = 1 or lower) and then added soda bicarbonate and magnesium sulphate (Scott Rao recipe, I lowered the soda bicarbonate amount added to have my KH similar to the KH of Scott Rao water made with RO water). The results (taste tests) were not as good as with the Scott Water made with RO. Flavours were somewhat blurred and I did not get the same clarity.

Filtering the water twice and testing the water is too much hassle to get a result that is not near perfect, so I now go the RO + minerals way. I was a bit against it at the beginning because, much like millmountain, I am buying it in 5L and I am not so much happy with the amount of waste and a possible leaching of harmful organic compound from these containers that are made to store food and drinks. I am now considering a RO setup, the small capacity one are not too expensive...

Adding Ca and possibly other minerals:
I do have the impression that having some Ca in the water enhances shot body and aftertaste, while Mg (or is it the sulfates???) do bring out the different flavours and enhance clarity. That is just some impressions I gathered while testing different waters, but it happens to concur with Hendon's findings, so maybe it is worth considering. I now add about 5% of my tap water (GH about 16) to the Scott Rao recipe and my first impression is that it helps.

Taste is not linear so small amounts may possibly have a significant effect on the way the shot tastes, a bit like salt does on our food. One other thing that is not clear is how other minerals may influence the extraction itself. Finally, humans evolved drinking water that as a wide range of minerals in it, so this maybe why RO tastes weird and adding homeopathic amounts of other salts (and maybe even table salt NaCl) may taste better to us. Just thinking out loud here but maybe I will try adding some small amounts of other elements to end up with something that as a profile more similar to a spring water.

The idea of natural balance in natural water is an interesting one. Aquacode sells themselves on it. I have copied my post from another thread as it maybe of interest. This is a softer espresso water and maybe not to the proportion most people aspire but i was looking for a softer water. Aside from how easy it is i like that is had some calcium but hopefully not enough to scale, suitable KH and low sulphates and chlorides. It would work if you wanted a lower or higher total hardness but works well for this. I really like it at the moment, clear flavours and not too in your face so more of the different flavours seem to stand out.... I've only used it a few weeks. I do wonder if the natural proportions of the spring water have an additional value?

Previous post included
Someone put me into this and I like the results so far. I was looking for a softer espresso water with around 40 ppm alkalinity. It's very easy to make and i like the fact that it's low in sulfate and chlorides. If you try to make this with the usual minerals available you get much higher of both. Mix 150ml of Evian with 850 ml distilled water. This gives you calcium 29, mag 15, alk 44 (caco3 equiv). 1.5 mg sulphate and 0.75 chloride. As far as i know this should be fine for machine health and scale. Evian is not the cheapest but one bottle goes quite a way. You may be able to find another water with similar ratios to evian and could dilute that in appropriate quantities

lukehk wrote:Mix 150ml of Evian with 850 ml distilled water. This gives you calcium 29, mag 15, alk 44 (caco3 equiv). 1.5 mg sulphate and 0.75 chloride. As far as i know this should be fine for machine health and scale.

+1

This is a straightforward way to get into the conventionally recommended zone for non-scaling espresso machine water. Evian is like Volvic in that the water always comes from the same source. (as opposed to Crystal Geyser here in the US, which has 7 different sources.) Evian has reasonably low numbers for everything that you don't want (chloride, sulfate, silica), and when diluted to 85% distilled those numbers become insignificant.

For US bottled water, you could do something similar with Crystal Geyser if verified from the Johnstown NY source. That one has a total hardness of 180 mg/L and alkalinity of 140 mg/L CaCO3 equivalent. You could dilute that at 30% CG and 70% distilled to come out at:
total hardness: 54 mg/L (CaCO3 equiv)
calcium hardness: 42 mg/L (CaCO3 equiv)
alkalinity: 42 mg/L (CaCO3 equiv)
chloride ion: 9 mg/L
sulfate ion: 4 mg/L
TDS: 63 mg/L

non-scaling*, healthy alkalinity, low 'undesirable' minerals, hardness very close to water now used in WBC competitions.


* At 130℃, the Langelier Saturation Index at the Puckorius pHeq of 6.92 is 0.02, essentially neutral.

lukehk wrote:If you try to make this with the usual minerals available you get much higher of both.

That is indeed a straighforward solution to reduce Na, Cl, and SO4 in the water. You could use a fraction of about any water of known alkalinity and hardness and which is low in indesirable minerals and other contaminants as a source of HCO3, Ca and Mg.

Then if desired/needed you can still adjust the alkalinity/hardness ratio and/or the Mg/Ca ratio by using the usual minerals (sodium bicarbonate / magnesium sulfate...), but will need less of those and have a bit of Ca on top which I believe is nice to have.