Bottled water mix suggestions for espresso machine

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

#1: Post by francesco_ITA »

Few months ago I bought a Lelit Bianca and I started my wonderful espresso journey.

Tap water in our city is quite hard, therefore it is not an option for the Bianca. For reference, the city hall reports that the water hardness is between 29 to 31 fH (französischen Härtegraden - French degrees of hardness) equivalent to 290 to 310 CaCO3 mg/L (1 fH degree is equivalent to 10 mg/L CaCO3).

Because of this I started gathering different details about " the best water" for espresso for making not only good coffee, but also avoiding any damage the machine due to scale or potentially corrosive water. I have found many excellent posts and suggestions on this forum, but a lot of them result quite complex to me, especially when needing to use further tools or mixing minerals to distilled water (I am not that advanced yet).

Currently I am using bottled water with low minerals/hardness.
From many sources, Volvic Water: https://en.wikipedia.org/wiki/Volvic_(mineral_water) has been pointed as a good bottled water for espresso machines in order to avoid scale issues:



I mix this water (ratio 1:1) with another brand I found (having even less minerals):



Taste wise I really enjoy my espressos, even if Calcium and Magnesium values are pretty low.

Therefore I would like to have a confirmation whether this water combination is safe for the machine and I can keep using it or maybe it's too poor of minerals and I should change it. I also use Lelit water softener that came with the Bianca: https://lelit.com/product/water-softener-filters/

My goal would be to find an easy and practical solution, if possible.

In the past, for a short period, I used other brands like Evian: https://en.wikipedia.org/wiki/Evian



or Vittel: https://en.wikipedia.org/wiki/Vittel_(water)

But as far as I read they are too hard and rich of minerals, giving quite likely scale issues in the long term.

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homeburrero
Team HB

#2: Post by homeburrero »

francesco_ITA wrote:Therefore I would like to have a confirmation whether this water combination is safe for the machine and I can keep using it or maybe it's too poor of minerals and I should change it.
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.

The Evian and the Vittel waters you listed are way too hard. They would quickly exhaust the softener capacity of that LeLit filter.

P.S. to see how to do these kinds of unit conversions: Good references on water treatment for coffee/espresso
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

francesco_ITA (original poster)

#3: Post by francesco_ITA (original poster) »

Many thanks for the confirmation about my water and the excellent link!

nick_111

#4: Post by nick_111 »

homeburrero wrote: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.

The Evian and the Vittel waters you listed are way too hard. They would quickly exhaust the softener capacity of that LeLit filter.

P.S. to see how to do these kinds of unit conversions: Good references on water treatment for coffee/espresso
I have a Lelit Bianca as well and I am currently considering of using the following water mix: Evian water (at 15%) and deionized water (at 85%).

This should give (in units of CaCO3 equivalents):
Calcium hardness: 30 mg/L
Magnesium hardness: 16 mg/L
Total hardness: 46 mg/L
Alkalinity: 44 mg/L

And chloride (as ion): 1,5
sulfate (as ion): 2,1
and a TDS of 52.

This seems to be safe as far as limescale is concerned but I am not sure about corrosion. In particular, I am puzzled by the following fact: when I enter the above calcium, alkalinity and TDS numbers into the following Limescale and corrosion prediction calculator, the prediction that I get is that the water is very corrosive for the brew boiler and should not be used in espresso machines (see photo at the end).

Is this prediction correct ? If yes, could one please explain why this is the case and what needs to be corrected in the water ? I would really appreciate your help on this issue because I am quite confused.


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homeburrero
Team HB

#5: Post by homeburrero »

nick_111 wrote:Is this prediction correct ? If yes, could one please explain why this is the case and what needs to be corrected in the water ? I would really appreciate your help on this issue because I am quite confused.
No, it is not correct. This prediction is based on a common oversimplification that assumes that negative LSI values are an indication of corrosion. A negative LSI simply indicates that limescale will tend to be dissolved rather than deposited and is not necessarily an indication of corrosivity. This particular calculator will give you that very alarming message whenever you have non-zero calcium and the LSI is below -0.5.

Corrosion is way more complex than what you get from an LSI number. In the past it was often claimed that limescale was protective against corrosion, and lack of limescale was therefore corrosive -- but that's a gross oversimplification, especially in espresso boilers. Limescale is porous, and is not evenly deposited and not that protective. Other things, like chloride ion, sulfate ion, low alkalinity, and exposure to acids are more important than LSI in evaluating corrosivity in coffee boilers.

Your water mix is a good example of non-scaling water with healthy alkalinity, neutral pH, and low chloride and sulfate numbers. It will not deposit limescale but it is also nicely non-corrosive. Since it doesn't deposit limescale you won't need to periodically descale it, and descaling solutions are certainly corrosive.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

nick_111

#6: Post by nick_111 » replying to homeburrero »

Thank you so much for your help and your response! It was quite enlightening.

I am trying to infer some simple criteria that could be applied when mixing bottled water with demineralized water so as to get a water mix that is machine-safe, i.e., never need to descale (even in a hot steam boiler) and without having to use a Lelit water softener.

Is it safe to say that one set of such criteria could be the following ?
- calcium hardness (in CaCO3) <= 40 mg/L (is this considered a bit too high already in terms of limescale or would it be OK to go even higher than that ?)
- alkalinity (in CaCO3) >= 40 mg/L AND <= 50 mg/L (lower than 40/higher than 50 might lead to corrosion/scale problems ?)
- chlorides <= 10 mg/L
- sulfates <= 15 mg/L (I guess this could be relaxed more)

I could use such info to also experiment with some other local bottled waters that are a lot cheaper (here in Greece) than Evian or to try to increase a bit more the total hardness while remaining machine-safe (e.g. La Marzocco recommends a minimum 70ppm total hardness).

More generally, I think this type of information could be useful to other users that (like me) do not have so much experience with water for espresso and seek a simple solution such as mixing of bottled water with demineralized water.