Total Hardness and Calcium Hardness

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
Psychoav

#1: Post by Psychoav »

I'm at the stage of understanding how water could affects our brewing taste and espresso machine longevity. After reading some books and articles over the internet, I have sort of knowing the importance of Total Hardness and Total Alkalinity. I want to invest more on testing equipments to understand my home water content, so I want to go for a photometer. I saw there is photometer for measuring Total Hardness (CaCO3) and another photometer for measuring Calcium Hardness (mg/L). Besides Total Hardness, is it better to get to know the proportion of Calcium content within a Total Hardness readings? And I have seen those photometer can only obtain a range of Calcium Hardness up to 2.0 mg/L, which is way below of recommended range for coffee brewing, am I having a misinterpretation to the readings? Thanks

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homeburrero
Team HB

#2: Post by homeburrero »

Psychoav wrote:I want to invest more on testing equipments to understand my home water content, so I want to go for a photometer. I saw there is photometer for measuring Total Hardness (CaCO3) and another photometer for measuring Calcium Hardness (mg/L).
If you're in the business of analyzing water then you can justify the expense of a photometric analyzer that you calibrate in the morning and spend the day analyzing many water samples. For a coffee shop or home barista you're better off with simple drop titration kits. Good drop titration kits for total hardness, calcium hardness, alkalinity, and chloride are available at reasonable prices. Inexpensive and easy-to-use drop titration kits for hardness (GH) and alkalinity (KH) are available from API fishcare. Drop titration kits that purport to measure 'carbonate hardness' are actually alkalinity test kits. (For most natural water, where the alkalinity is all due to carbonates, and where the total hardness exceeds the alkalinity, alkalinity and 'carbonate hardness' are essentially equal.)

When you need better precision at low values these drop titration kits can be stretched. For example if you wanted to verify that your total hardness was close to but not much more than 50 mg/L CaCO3 equivalent and you had an API kit with a 5 ml sample where 2 drops corresponded to 35 mg/L and 3 drops corresponded to 53 mg/L, then you can use the same kit on a 20 ml sample so that 10 drops is about 44 mg/L and 11 drops is about 49 mg/L.


Psychoav wrote:Besides Total Hardness, is it better to get to know the proportion of Calcium content within a Total Hardness readings?
Most people don't bother measuring calcium hardness vs total hardness. It's good enough to know that your calcium hardness is always something lower than the total hardness, so if you use the total hardness number when making limescale deposit estimates then you can take comfort that if anything you may be overestimating your scale deposit rates.


Psychoav wrote:And I have seen those photometer can only obtain a range of Calcium Hardness up to 2.0 mg/L, which is way below of recommended range for coffee brewing, am I having a misinterpretation to the readings?
You will see different ranges for different gadgets. This one, for example does up to 400 mg/L calcium (which is up to 1000 mg/L CaCO3 equivalent calcium hardness). But the accuracy of ±10 mg/L ( ± 25 mg/L CaCO3 equivalent) is not that good. With the more sensitive analyzers you can dilute your sample with a measured amount of distilled to test water that's above the meter's range.
Pat
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Psychoav (original poster)

#3: Post by Psychoav (original poster) »

Thank you so much for the information