Bottled water mix suggestions for espresso machine - Page 2

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

Not yet. I found just evian and distilled very clean tasting. Never had a problem with it. I just thought I would try increasing it more in line with some recommendations on the decent forum. My use.of it for espresso has been limited though as I've been playing around with Rao's filter 2.0 profile which is longer 1:5 ratios with a 2 minute bloom and 1.5 ml flow. Diluted after to 1-15 ratio. Maybe could see more difference with more traditional espresso/ratio.

nick_111

#12: Post by nick_111 »

I have been trying the evian-based water recipe (15% evian, 85% distilled water) for 2 weeks now and I must say that I really like the results (i.e. taste of coffee) so far. It is highly recommended for anyone searching for a simple water solution that is machine-safe. Should be easy to get something quite similar with other bottled waters as well.

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francesco_ITA (original poster)

#13: Post by francesco_ITA (original poster) »

As they stopped selling the soft bottled water I was used to mix (50:50) with Vittel water (minerals details in the first post page), I went doing some math using the formula as described in Good references on water treatment for coffee/espresso, however I could not get the same results as proposed by homeburrero:
That 50:50 mix of Volvic and your softer water looks reasonable to me. In units of CaCO3 equivalents it gives you:
Calcium hardness: 25 mg/L
Magnesium hardness: 20 mg/L
Total hardness: 45 mg/L
Alkalinity: 40 mg/L

And chloride (as ion) of 8 mg/L

Even without any softening by the LeLit filter it should not give you limescale problems, and the alkalinity is right on for corrosion protection.
For the total hardness:
mg/l (ppm) of [Ca²⁺] ion by 2.5 (to get calcium hardness)
mg/l (ppm) of [Mg²⁺] ion by 4.12 (to get magnesium hardness )
Then add calcium hardness and magnesium hardness to get total hardness
With my two waters mix, I got:

Ca²⁺ (12mg/L + 8,2 mg/L ) * 2.5 = 50.5 mg/L
Mg²⁺ (8mg/L + 1,5 mg/L ) * 4.12 = 39.14 mg/L

This would give me a total hardness of: 89.6 mg/L or ppm of CaCO3 (instead of 45mg/L)


To calculate the total alkalinity:
mg/l (ppm) of [HCO₃⁻] ion (bicarbonate) by 0.82 (to get bicarbonate alkalinity)
mg/l (ppm) of [CO₃²⁻] ion (carbonate) by 1.67 (to get carbonate alkalinity)
Then add bicarbonate alkalinity to carbonate alkalinity to get total alkalinity.
HCO₃⁻ 74 mg/L + 24 mg/L * 0.82 = 80.36 mg/L
CO₃²⁻ I cannot infer this information from the bottle label

However I cannot understand how an alkalinity of 40 mg/L can be reached when the bicarbonate alkalinity is already at 80.

Probably even reading the math steps on the other posts I missed something, in that case sorry for the silly question, however I cannot find a way to match the different values. Thanks homeburrero for the patience!!

nick_111

#14: Post by nick_111 »

You are ignoring the fact that you are mixing 50% of each water. That means you need to multiply by 1/2 each number.
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homeburrero
Team HB

#15: Post by homeburrero »

nick_111 wrote:You are ignoring the fact that you are mixing 50% of each water. That means you need to multiply by 1/2 each number.
Nikos is spot on. Each value in a mix needs to be multiplied by its fraction of the mix. In your bicarbonate example:

HCO₃⁻ : 74 mg/L * 0.5 + 24 mg/L * 0.5 = 49 mg/L
And converting that to CaCO3 equivalent, 49 * 0.82 = 40.2
francesco_ITA wrote:CO₃²⁻ I cannot infer this information from the bottle label
The amounts of carbonate (CO₃²⁻ ), bicarbonate (HCO₃⁻ ), and carbonic acid (H₂CO₃) are all part of a shifting chemical equilibrium. When the pH is below around 8.3 you can simply assume that the amount of carbonate ion is negligible and all the alkalinity is due to bicarbonate.
Pat
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francesco_ITA (original poster)

#16: Post by francesco_ITA (original poster) »

Indeed...the 1/2 factor, little but crucial details, all good, thanks again nick and homeburrero!!

francesco_ITA (original poster)

#17: Post by francesco_ITA (original poster) »

The alkalinity value of 40 is still acceptable or being exactly at the lower bound it might lead to potential corrosive issues if the mix is not always exactly 50:50?

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homeburrero
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#18: Post by homeburrero » replying to francesco_ITA »

I think it's fine. Even if you mixed 40:60 (with more of the softer water) you'd come out at 36 mg/L CaCO3 equivalent, which is close enough to 40. There really isn't a falling-off point at 40, it's just a reasonable number to advise if you have to choose one. (The old SCAA guidance that people have followed for years simply advised an alkalinity "at or near" 40 mg/L.)
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h