As our water at home is extremely hard (29 to 31 fH degrees), we used for our Lelit Bianca a mix of bottled waters: Volvic and another local brand with few minerals, making a good combination in terms of TDS and minerals. Unfortunately, the local water got dismissed, and since I could not find any alternative, I plan to try with Dr. Pavlis's receipt.

The problem is that here (in Switzerland / South Germany), I cannot find any distilled water (unless Bi-Distilled for clinical machines, and it states clearly not to drink it). Amazon Italy/Germany also did not provide any good results.

Supermarkets only have "demineralized" water (labeled as "like distilled"), due to lower production costs I guess.
I wonder how healthy it would be to use this water for coffee as nowhere is it indicated that it could be drinkable, but rather aimed to be used for cars' batteries or ironing. I am concerned about which kind of substances, aside from possible bacteria, would be in it.

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For completeness, the Volvic mineral values are below (the arrow for the minerals that leaves me with some thoughts).

What is the scale issue using only Volvic water? Eventually, would a Brita Filter with Volvic water bring any benefits to avoid scaling?

Calcium 12
Sulphates 9
Magnesium 8
Sodium 12
Bicarbonates 74
Potassium 6
Silica 32 <--
Chlorides 15 <--
Nitrates 7.3
Dry Residue 130mg (at 180*C)
PH 7

francesco_ITA wrote:I am concerned about which kind of substances, aside from possible bacteria, would be in it.

Yes, If it's not labeled as suitable for drinking I would advise not risking it. Besides pathogens there could be part per billion traces of heavy metals or toxic organics in the water, and they aren't testing to verify that it meets drinking water standards for that.

francesco_ITA wrote:What is the scale issue using only Volvic water? Eventually, would a Brita Filter with Volvic water bring any benefits to avoid scaling?

Many people on this site have reported using straight Volvic with no scale issues. Note that it has a fairly low calcium hardness (12 mg/L translates to 30 mg/L CaCO3 equivalent or 3 French degrees) and sulfates are low. The Silica is perhaps a bit high, so it's a good idea to take care to periodically flush the steam boiler if you do a lot of steaming. The bicarbonate, at 74 mg/L is equivalent to 62 mg/L alkalinity as CaCO3, which is about right for corrosion protection. Using a Brita might lower that alkalinity and acidify the water a little, which in theory might exacerbate chloride corrosion, so I would not do that. You don't need the Brita's charcoal here because the Volvic has no chlorine nor chloramine.

perhaps good to add that distilled water while potentially not the best to drink as source of water will be replenished with minerals when used to make coffee.

Thank you all for the replies.

On average, we have one cappuccino and two double espressos, so I think we do not use the steam much. I do not use the boiling water wand at all, except extracting some old water from the boiler from time to time.

I have found Laureatana water as a soft water alternative to use with the Volvic. Pat, from your experience, could you please suggest to me a mix that would avoid corrosion risks and, if possible, also scale issues?
The machine still has 1 year warranty, therefore, if possible, I would like to avoid emptying the steam boiler regularly (however, if this is a generally good practice, I will definitively look into it. Any hints about how often it should be done?).

Below are the details of the two kinds of water:

Lauretana
Calcium ___ 1.1mg/L
Magnesium _ 0.3mg/L
Sodium ____ 1.08mg/L
Potassium __ 0.32mg/L
Sulphates __ 1.55mg/L
Chlorides __ 0.53mg/L
Nitrates ___ 1.4mg/L
Silica _____ 5.3mg/L
Bicarbonates 4mg/L

Total Dissolved Solids 13.9mg/L
pH (at source) 5.75

Volvic
Calcium _____ 12mg/L
Sulphates ____ 9mg/L
Magnesium ___ 8mg/L
Sodium _____ 12mg/L
Potassium ___ 6mg/L
Silica ______ 32mg/L
Chlorides __ 15mg/L
Nitrates ___ 7.3mg/L
Bicarbonates 74mg/L

Dry Residue 130mg (at 180*C)
PH 7

I will still look for a safe distilled water as I would aim to follow Dr. Pavlis's recipe.
Can anyone suggest a reliable TDS/PH meter? The ones I can find on Amazon or Aliexpress (often the same) are not exactly precise, making them useless if they are not reliable.

You would be fine using that Lauretana in place of distilled in any rpavlis recipe -- you would simply add about 0.1 mg of potassium bicarbonate (or about 0.08 gram of sodium bicarbonate) to each liter. If spiking a 750 ml bottle you would want to use a concentrate.* I don't see prices though and it looks like it might be costly with a lot of bottle waste.

If you were to mix Laurentana and Volvic at 50/50 you would still have reasonable alkalinity (about 30 mg/L CaCO3 equivalent) for corrosion protection with the resulting mix reliably scale free and nicely below conservative recommendations for chloride and silica.

francesco_ITA wrote:Can anyone suggest a reliable TDS/PH meter?

Even the cheap conductivity TDS meters are pretty reliable, especially if you're careful to read them withn the water at 25 C. All TDS conductivity meters have the problem that they measure conductivity and not TDS, and the conversion factor for estimating TDS from conductivity can vary fairly widely depending on the content of the water. For this purpose an inexpensive one is fine.

Measuring pH is a different issue. The pH of water can vary widely depending on the amount of dissolved CO2 in the water. Water from a tap or from a bottle may release or absorb CO2 to/from the atmosphere in an open container and the pH will change. It's best to look at the alkalinity rather than pH, and alkalinity can be calculated in a recipe or water spec, or can be measured with an alkalinity or KH drop titration kit.


* See Easiest way to make rpavlis water? for a plethora of options. In the case of 750 ml bottles, you could make a concentrate using 9.6 grams of potassium bicarbonate to a 750 ml bottle of that Lauretana water and keep that in the refrigerator. Then every time you add a bottle of the Laurentana to your machine reservoir you would add 15 - 30 grams 3 - 6 grams of water from that concentrate water. 30 6 grams would give you the full strength rpavlis recipe with an alkalinity around 50 mg/L CaCO3 equivalent and an ideal slightly basic pH.

[Correction. Initially had the numbers right for a 1 gallon bottle, then quickly corrected it with strikeouts for the 750 ml bottle]

francesco_ITA wrote:The machine still has 1 year warranty, therefore, if possible, I would like to avoid emptying the steam boiler regularly (however, if this is a generally good practice, I will definitively look into it. Any hints about how often it should be done?).

With non-scaling water you can use a routine of pulling some water out of the water tap before using the steam wand. See Using hot water tap to manage steam boiler water concentration

Thanks again Pat, you are always extremely helpful.

A box of 6 Laureatana bottles of 1.5L cost around 12$, not on the cheap side for water, but definitely worth it if I can preserve the Bianca's correct functioning. Costs aside, would you personally recommend only Lauretana (using 6 - 12gr concentrate per bottle, where the concentrate is made with 19.2gr potassium bicarbonate in a 1.5L bottle) or Volvic + Lauretana?
Eventually, would it make sense to add some potassium bicarbonate to the Volvic + Laureatana mix to increase alkalinity or would it be pointless?

At the moment, when I pull some water out of the boiling wand, I notice that a couple of very small black particles come out eitj the water (hoping maybe some kind of "normal" dust/dirt and not some part of the steam boiler wall). I hope with the new water receipt and routine I won't see anything anymore.

francesco_ITA wrote:Costs aside, would you personally recommend only Lauretana (using 6 - 12gr concentrate per bottle, where the concentrate is made with 19.2gr potassium bicarbonate in a 1.5L bottle) or Volvic + Lauretana?

Yes, that works out for a 1.5 liter concentrate bottle, and spiking 1.5 liter bottles of the Laurentana. 12 g of that concentrate per 1.5 liters would be much like the full strength rpavlis that many people use.

francesco_ITA wrote:Eventually, would it make sense to add some potassium bicarbonate to the Volvic + Laureatana mix to increase alkalinity or would it be pointless?

Probably not necessary but would not hurt and theoretically would be better from a corrosion risk perspective. If you were to add 6g of that concentrate above it would bump the alkalinity of the 50/50 mix from appx 30 mg/L to around 55 mg/L. The scale risk would increase slightly in theory but in reality would not be a concern because the calcium hardness of that mix, in the 16 mg/L (as CaCO3) neighborhood, would be so low.

Then I will probably follow the Volvic + Lauretana mix with the addition of the concentrate (maybe not full Pavlis strength) to get good water without excessive costs (ordered 3 boxes - 6x1.5L of Laureatana and with shipping costs, it came to a total of 43$ ).

Thanks again Pat for all your hints.