RO vs. Distilled Water Reminiralization

Ibrahim

Hello Everyone,

A tiny question about water:

RO systems are recommended, but the cost of service in my country is stupidly high and the same time I can get distilled water in good prices.

Now Let’s say that I want to reminiralize my distilled water with Sodium Bicarbonate, so will it be similar to RO water (manualy reminiralized not reminiralization filter)? or there’s something am missing here?

Note: all this with careful testing of pH and correct amounts to reach ideal alkalinity.

Thanks

MWJB

Ibrahim remineralising with sodium bicarb won’t necessarily make distilled like RO. Just add enough to meet your alkalinity preference, 40-60ppm as CaCO3 is a typical target range.

Cuprajake

The terms can be mixed up

Ro water still has some stuff in them,

Rodi and distilled have nothing in them

You can use sodium or potassium

Ibrahim

Let’s say I am comparing RO water from Osmio Zero (with no reminiralization) to distilled, still the same case?

Rob1

Ibrahim The RO will have some hardness and alkalinity remaining (and other things) whereas distilled is boiled and condensed so everything is left behind.

Sodium bicarb adds alkalinity but no hardness so distilled with sodium bicarb will not be the same as water from RO without sodium bicarb.

P.s you need to calculate how much sodium bicarb to add and are best testing with an KH drop kit to confirm rather than measure pH.

Ibrahim

Rob1

Thanks a lot rob.

Oh just realized the KH part, then I’ll check a safe way and concentration to add some hardness ( any advices for adding hardness?)

Distilled seems like an excellent option with remineralization.

Rob1

Ibrahim

It depends on the machine and your use. If you are using a service boiler or using a steaming function then you’ll need to consider how the minerals in the water concentrate and precipate as scale.

OldGregg The spreadsheet linked to above says “no calcium to precipate as scale” but unfortunately ignores the presence of magnesium, which also precipates as scale. Bear in mind too that the boiler temp is higher than 95c, if not for all machines then at least the majority of E61s.

I’d avoid adding any hardness using sulfate and chloride salts and just target an alkalinity of 40-60mg/l.

OldGregg

I’ve got a a 6 stage RO system, and even without the “mineralization” filter it still has about 30ppm of something when measured with a TDS meter. So it may be close to 0ppm, but its not the same purity as distilled.

I use this calculator to then find a recipe that is within ideal parameters given boiler temp etc.

Calculator -

Source-

https://www.espressoschool.com.au/coffee-water-calculators/

OldGregg

Rob1

That makes a reference to LSI, or the Langelier Saturation Index, which measures calcium carbonates affinity to scale at a certain ph/temp.

@Rob1 Most water recipes you will find online don’t suggest not having any hardness for “reports” it can produce a weak tasting cup , but if it works for you keep going with your recipe!

@Ibrahim Best of luck on this rabbit hole!

Rob1

OldGregg

Water will vary significantly in terms of corrosive and scaling potential in espresso machines. It isn’t possible to maintain a nearly neutral LI that is neither corrosive or scale forming. In steam boiler applications if any hardness from Magnesium or Calcium is present with bicarbonate then you’ll see scale forming as the minerals concentrate (assuming you start with a neutral or nearly neutral LI at the operating temp). Similarly, in a brew boiler, you may achieve a nearly neutral LI when it is up to temperature, but it will be corrosive when the machine is off and the water cools down to room temp. Whether it is a dual boiler or HX machine it isn’t practically possible to achieve this balance in both boilers (or boiler and HX) simultaneously, especially when most people will be turning the machine off at some point….a far greater risk of corrosion comes from chloride and sulfate presence (with sulfate-reducing bacteria) depending on boiler material, especially if scale forms.

The water recipes recommending hardness generally go with the idea that hardness influences extraction. Even tests involving gas chromatography are contradictory on this. As far as anecdotal reports re flavour are concerned, you will find they vary wildly. Some say magnesium produces a fruity cup, some say Calcium does, and some say coffee made from distilled water is best. My recipe uses Magnesium Bicarbonate and Sodium Bicarbonate, but it is not something I can recommend and flavour difference is minor compare to bicarbonate alone.

OldGregg

Rob1
That was really concise - thanks for clarifying that. Can I ask why you wouldn’t recommend your recipe?

Rob1

OldGregg A few reasons. It requires carbonating distilled water to make the concentrate for a start and precise measuring with a titration kit to confirm measures are correct and people tend to have trouble accurately using titration kits to begin with. People generally want to avoid scale build up in machines and avoid maintenance. Since I don’t know the machine people are using I just assume the worst; that it’s easily damaged by small amounts of scale and they are not comfortable performing maintenance themselves. Adding hardness just makes things more complicated in terms of preventing scale too - it’s still easily possible but requires extra routines. Most people just want to treat their water and then forget about it.

OldGregg

Rob1

Yea I found some of your previous posts - sounds like you have it dialed in. You spooked me on the chloride and sulfate front and opened both my boilers today to have a look inside - I still descale occasionally…. but they look okay!

Thanks for the input Rob!