Remineralise Water - Page 2

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
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homeburrero
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#11: Post by homeburrero »

Loreo123 wrote:And yep, my espresso machine is solely going to run with the Espresso Formula - do you think going with 2x Espresso Sachets into 5 Liters is fine as well or could that be problematic for my machine? (I kind want to experiment with the mixes (is that a word?) and see if there's a "gold spot" for me!)
I think it would be fine. Dissolving 2 x 2L sachets into 5 liters is close enough that it is essentially the same as the full recommended strength. Instead of a total hardness of about 161 mg/L you 'd have 129 mg/L - still much higher than most coffee water recipes. The alkalinity would still be 30 - 40 mg/L.

Unless your taste buds are way more sophisticated than mine I doubt that fine tweaking the water hardness levels is going to make much difference. Consider the fact that the water percolating through the coffee bed is loaded with minerals that come from the dissolved coffee itself -- the water coming out of the portafilter will have a magnesium content in the neighborhood of 3400 mg/L as CaCO3, so it's logical that the small amount in the incoming brew water may not make much difference. Many people on HB use the rpavlis recipe, which just has a little sodium or potassium bicarbonate and no hardness minerals at all and find that it tastes fine.



P.S.
Showing some TWW numbers FWIW ...

A while back Taylor Minor (bigdaub on HB) shared some of his recipe info here:
Third Wave Water capsules - add to water for better tasting coffee

For 1 gallon packets:
Classic 1500mg
Magnesium Sulfate 1100mg
Calcium Citrate 300mg
Sodium Chloride 100mg

Espresso 1500mg
Magnesium Sulfate 1050mg
Calcium Citrate 300mg
Potassium Bicarbonate 150mg
The Magnesium Sulfate he uses is actually finely ground Epsom Salt - magnesium sulfate heptahydrate. And I assume that the calcium citrate is anhydrous. Crunching these numbers, the espresso formula gives you a magnesium hardness of 113 mg/L as CaCO3, calcium hardness of 48 mg/L as CaCO3, total hardness of 161 mg/L as CaCO3, and bicarbonate alkalinity of 20 mg/L as CaCO3. Total alkalinity (buffer capacity down to pH 4.2 - 4.5) would be affected due to that calcium citrate, and my guess is that it would be in the 40 - 50 mg/L ballpark.
Pat
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jeffpresso
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#12: Post by jeffpresso »

homeburrero would the high hardness combo with relatively low alkalinity make TWW espresso profile at risk of corrosion? IThe graph in the SCA water book seems like it might.

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homeburrero
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#13: Post by homeburrero »

jeffpresso wrote:homeburrero would the high hardness combo with relatively low alkalinity make TWW espresso profile at risk of corrosion? IThe graph in the SCA water book seems like it might.
Good point, as that top line of the SCAE core zone* is where it is because of the corrosion risk associated with high non-carbonate hardness. That top line represents a GH:KH ratio of 1.8, and even allowing for citrate contributing to alkalinity, I'd put the TWW espresso formula at around 160:45, a ratio of 3.6, way above that line.

That upper line is prudent for natural tap water where high non-carbonate hardness typically means high chloride and sulfate anions, both of which increase corrosivity with chloride being much worse than sulfate.

In the case of TWW and recipes like 70/30 and Barista Hustle that use Epsom salt for hardness, I think you have less to worry about here because although the sulfate may be very high, the chloride is zero. If you want to eliminate that sulfate corrosivity risk, the practical alternative is to use a simple bicarbonate recipe (i.e., rpavlis). If you want some hardness in your recipe but want to minimize corrosion risk, use enough bicarbonate to have 40 ppm CaCO3 alkalinity, avoid any chloride salt , and use magnesium sulfate salts sparingly.


* That line is pictured in the graph here: Good references on water treatment for coffee/espresso , with more discussion from Marco Wellinger here: SCAE Water Chart is available online .
Pat
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jeffpresso
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#14: Post by jeffpresso »

I'm definitely going to try the potassium bicarbonate and magnesium sulfate. Is there a quick check to determine that the Epsom salt is in fact magnesium sulfate heptahydrate by using a water TDS electrical meter? I'd hate to end up doubling the hardness if was anhydrous, or maybe all Epsom salt is reliably in that hepahydrate form. I guess a more general question is it useful to perform a test to verify KH/GH values for the remineralized water.

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homeburrero
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#15: Post by homeburrero »

If it's labeled Epsom I think you can safely assume that it's the heptahydrate (molar mass 246.5 g/mol) and not anhydrous (120.4 g/mol).
jeffpresso wrote:Is there a quick check to determine that the Epsom salt is in fact magnesium sulfate heptahydrate by using a water TDS electrical meter? I'd hate to end up doubling the hardness if was anhydrous, or maybe all Epsom salt is reliably in that hepahydrate form. I guess a more general question is it useful to perform a test to verify KH/GH values for the remineralized water.
You could do a rough sanity check by dissolving 0.5 gram in a liter of purified water and checking it with a TDS meter. If it's fully dissolved Epsom it would read about 390 uS/cm at 25C, or about 195 ppm on a typical inexpensive (NaCl calibration factor) TDS meter. If it's anhydrous it would read about 705 uS/cm, about 350 ppm.

The conductivity check should be sufficient, but if you want to back it up with a GH drop titration it would be about 205 ppm CaCO3 for the Epsom and about 415 ppm CaCO3 for the anhydrous.

P.S.
I got those conductivity estimates from a handy online calculator: http://www.aqion.onl/show_ph
Pat
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