Hi!

For my espresso machine, I've been looking in to switching from filtered tap water (through a Brita filter jug) to either distilled water + sodium bicarbonate + epsom salt ... or ... bottled water.
The reason why I am actually considering bottled water is that distilled water is about 3 times as expensive (and surprisingly hard to come by) in my local area.

I've found a particular brand of bottled water with the following declared mineral content (mg/l):
Hydrogen carbonate 140
Sulphate 3
Chloride 11
Magnesium 15
Sodium 10
Nitrate <0,5
Calcium 22

Hardness: 6 dH
pH: 7.6

What do you think about the "specs" of the water?
Is the calcium content low enough to prevent limescale?
Is the alkalinity high enough?

That bottled water is a tad hard. Converting to measurement units favored by most coffee people it has:

alkalinity: 114
calcium hardness: 55
total hardness: 117
(all in units of mg/L or ppm CaCO3 equivalent)

Most of its hardness is due to magnesium instead of calcium, but despite that those numbers predict light scale in a steam boiler. (At 125C and pH = 7.6, you get a Langelier Saturation Index of about 1.1, which indicates light scale).

If you were to mix it about 50:50 with distilled or otherwise purified you would have non-scaling water with a perfectly healthy alkalinity.

Thanks a lot for your input. It's incredibly valuable.
I have a question regarding mixing the bottled water with distilled water. The distilled water I can buy has a pH of 5. Wont my 50:50 mix end up with a too low pH? Or will the alkalinity of the bottled water keep the pH from falling too much when adding distilled water with a pH of 5?

Also, regarding the distilled water: How can I make sure that the distilled water is perfectly safe for consumption? Chlorine, benzen and other chemicals with a boiling point higher than the boiling point of water will remain in the distilled water, unless they are filtered out.
I measured the TDS of my distilled water to 1 TDS. Does this mean that it's more or less perfectly pure? Or are there some unwanted compounds that are not "caught" in a TDS measurement?

sorenwrang wrote:Wont my 50:50 mix end up with a too low pH? Or will the alkalinity of the bottled water keep the pH from falling too much when adding distilled water with a pH of 5?

The alkalinity will raise that pH. A 50:50 mix, which would give you about 57 mg/L alkalinity should end up with a well above neutral pH after equilibrating with CO2 in the air. The Puckorius pHeq, which you'd use to make scale predictions would be 7.1.

sorenwrang wrote:Also, regarding the distilled water: How can I make sure that the distilled water is perfectly safe for consumption?

Good point. We have seen posts about industrial distilled or de-ionized that is labeled as not potable. And water could be less than 1 ppm and still not be up to drinking water standards for heavy metals, organics, or microbes. Just make sure that your distilled water is labeled as suitable for human consumption and I think you're fine.

homeburrero wrote: Good point. We have seen posts about industrial distilled or de-ionized that is labeled as not potable. And water could be less than 1 ppm and still not be up to drinking water standards for heavy metals, organics, or microbes. Just make sure that your distilled water is labeled as suitable for human consumption and I think you're fine.

It's not labeled as neither safe nor unsafe or consumption. I've contacted the manufacturer and am now waiting for their reply.
Wouldn't a charcoal cartridge filter, like a Brita or BWT filter jug solution, get rid of any heavy metals etc. remaining in the distilled water?

It's surprising that standard consumable distilled water isn't readily available in your area. Consumption safe distilled water has myriad home applications, and thus even my local grocery store keeps the shelves stocked. People use distilled water in lots of home and medical applications such as cpap machines, humidifiers, fish aquariums, and many others. Have you checked your local drug store/pharmacy? Maybe find an aquarium hobby store? I use distilled water in my water solution, and I can get gallon jugs anytime I want for less than a dollar. It would be difficult for me if it wasn't so readily available.

I am quite baffled (and frustrated) as well.
I should also correct myself - I have bought demineralised water and I actually doubt that it has been demineralised through distillation - it's probably RO or ion exchange.
I can buy demineralised water everywhere but most of it is through ion exchange, and probably not food grade.

The only distilled water I can buy is farmaceutical grade (sterile) from the farmacy. But it costs 5 times as much as demineralised water - it's around 5 dollars per litre.

I have now contacted the procurement division of the retailer that sold me the demineralised water. I'll ask to be connected to the manufacturer, if possible, so I can ask what process they've used and if the water is safe for consumption.

If it turns out that they can not guarantee that it's safe for consumption, I think I'll go with the bottled water that I presented in the original post, well-knowing that it's a bit high on calcium .

I make my custom water starting with RO from a ZeroWater setup.
IMO, for the longevity of your boiler or for the taste of your coffee, RO is adequate.
If your issue is absolute health-oriented avoidance of trace substances, well...
...good luck. Distilled water can have contaminants in it, as long as they are below 'acceptible' levels.
Also, pharmaceutical distilled water is likely to have a preservative in it that does not have to be listed as an ingredient.
I learned this from my work with environmentally sensitive individuals.

Dont reinvent the wheel. Read the posts by homeburreo and rpavlis and you will learn more than you want to know. Use a recipe that can be gleaned from those threads.

P.S. Crystal Geyser is an acceptible ready-made source. They list their profiles from their various aquifers around the U.S.

Many supermarkets have a filtered water refill station. This would be an option for "better than tap water" for many. Combine that with a bottle pump and it expands some possibilities.

BuckleyT wrote:I make my custom water starting with RO from a ZeroWater setup.
IMO, for the longevity of your boiler or for the taste of your coffee, RO is adequate.
If your issue is absolute health-oriented avoidance of trace substances, well...
...good luck. Distilled water can have contaminants in it, as long as they are below 'acceptible' levels.
Also, pharmaceutical distilled water is likely to have a preservative in it that does not have to be listed as an ingredient.
I learned this from my work with environmentally sensitive individuals.

Dont reinvent the wheel. Read the posts by homeburreo and rpavlis and you will learn more than you want to know. Use a recipe that can be gleaned from those threads.

P.S. Crystal Geyser is an acceptible ready-made source. They list their profiles from their various aquifers around the U.S.

Well, the problem is that I'm not sure if the demineralised water I can buy is safe for consumption at all. It's not about reaching absolutely zero contaminants - it's about being absolutely sure that they are below an acceptable level.
As I've written above, I can't get my hands on any demineralised or distilled water that's labelled as safe for consumption - that's how it is here in Denmark, for some reason.