Keep the Osmio Zero water (without mineralisation)

Rob1 Could he minimise the scaling of the service boiler by refreshing the water in the service boiler ie opening the water tap after steaming or am I missing the point?

Rob1 was really hoping the use of osmio would negate the need for any of that but I’ll do what I need to, to keep everything in order! I might just use ro or di water for a few weeks instead of any descaling (I think I might have access to some lab de ionised water) and that might clear things up?

I read these posts and there is a lot of info and some of it can to me at least seem confusing. There are mentions of KH and GH and alkalinity. I thought to ensure i keep my machine at the minimum level of scaling: i do the following

1. Buy a water hardness kit but not the strips

2. Start by measuring the hardness of my tap water as a CaCO3 figure with the kit

3. pour the tap water in to either a skuma or OZ ( leave out the jug versions for this)

4. extract the water from the RO machine with all filters installed ie mineral filter included

5. take another reading of the hardness and ensure it is no higher than 80 ( around the 40-80 mgl mark)

6. Pour that water into the water tank of the espresso machine

7. if using steaming periodically then flush some water from the hot tap so that the minerals in the service boiler are not accumulating.

8. Once every 3 months recycle the water in the service boiler with fresh RO water so that very few minerals are left

9. Alternatively use RO water with no minerals. But in this case add bicarbonate of soda to act as an anti corrosive property in the RO water.

10. If your machine has stainless steel boilers then there is no need to add bicarbonate of soda as no corrosion will take place but you may still want to add it to improve taste

    
    

    I have tried to simplify the procedure so that it keeps scaling to a minimum. Would the above work? or is it over simplified?

JahLaza If you are just making americanos the water is ok and your 6 month refresh would be fine…probably. Probably better off just topping up from the osmio rather than using the service boiler just for energy efficiency.

coffeealex take another reading of the hardness and ensure it is no higher than 80 ( around the 40-80 mgl mark)

Not sure where you got that from. For the service boiler you’ll want hardness to be less than 40mg/l really if your alkalinity is 40mg/l too, but ideally, the hardness will be 0. While at 40KH you can have hardness up to 52GH at 125c, a very small increase in alkalinity will see the scaling potential increase quickly e.g 43KH at 125c and the threshold drops to 43GH…

So for service boilers water hardness is ideally 0 with 40mg/l or more alkalinity, and for brewing espresso you’ll get good results too. Adding hardness in means flushing/monitoring a service boiler and/or descaling.

coffeealex If your machine has stainless steel boilers then there is no need to add bicarbonate of soda as no corrosion will take place but you may still want to add it to improve taste

Stainless steel isn’t quite as corrosion resistant as surgical steel and you have other things though like copper pipes and solenoids, a brass group etc. Not a great idea to be putting distilled or straight RO through a machine. I pour it directly into the service boiler, it’s not completely risk-free, but it doesn’t stay pure for very long.

People who refresh the service boiler and use the remineralisation filter seem to be doing fine. If you want to just add bicarb you’ll probably be pleased with the results too. There’s no real need to complicate things.

Rob1 Thank you for your replies. Clearly your level of understanding of water is comprehensive. It has made me realise that although I am trying to simplify everything some basic understanding of water chemistry is helpful.

I am never going to have your level of Knowledge but the more I am reading the more the penny is dropping. So this is where I am now in my understanding:

Using and maintaining an espresso machine and keeping reliability to a maximum requires good quality water suitable for the machine. This is based on the initial and unequivocal fact that the quality of water is probably the number 1 factor to minimise short/ long term machine problems.

Starting from that baseline my understanding is that tap water is full of various minerals and that these will differ according to how the water is naturally filtered eg: there may be more chalky mineral salts dissolved into the water as it filters naturally which would make the water harder. Finally water authorities will add/ remove minerals to the water to purify it and/ or improve its perceived quality. The net result will be water that differs from area to area.

From an espresso machine point of view removing these minerals through reverse osmosis or jug filters would at first seem the logical solution. i.e. if we remove calcium and magnesium minerals ( principal causes of limescale formation) then this would be job done? If only it were that simple.

My understanding is that in so doing you are then affecting the PH level of water i.e. the acidity/alkalinity factor. Why does this matter? Well if you make water more acidic ( which is what happens when you remove all minerals) then corrosive factors come in to play. At first I thought Ok that only matters if you have brass boilers. Alas I also realise that although helpful having stainless steel boilers, a cursory look at most espresso machines will identify many brass pieces.

That then brings the fact that adding something back is helpful. Hence where bicarbonate of Soda comes in as it raises PH and hence alkalinity values. There is also a taste factor for some who may feel demineralised water may not taste great eg zero water. Although I wonder if that is going to differ from person to person as surely if you remove all minerals from water then are you not effectively tasting the inside of your mouth?

In conclusion for most a standard RO treatment with a few minerals put back in should do the job, along with some periodic refreshing of the service boiler along with an annual or half yearly check of the mushroom for signs of scaling. Ideally a simple wifi endoscope obtained at low cost from amazon inserted into each boiler would give a clear indication of how effective the quality of your water. something such as:

endoscope

Rob or anyone else am i starting to think along the correct lines or is my understanding still wide of the mark?

coffeealex Well if you make water more acidic ( which is what happens when you remove all minerals) then corrosive factors come in to play.

Removing minerals will not make water more acidic; neutral pH is by definition the pH of pure water. The problem is that pure water will tend to absorb CO₂ from the atmosphere, and that can turn it into a fairly acidic liquid. Buffering it with a weakly basic compound like bicarbonates (or weakly acid - but since coffee is acidic in nature very few people enjoy adding acid to it) keeps the pH close to neutral (within relatively large bounds). “Alkalinity” (as we use it in coffee making) doesn’t necessarily equate to a high pH.

If you remove calcium and magnesium compounds, or (bi)carbonate ions, scale won’t form. The problem is that Ca and Mg make coffee taste better to a large proportion of people, and bicarbonates are an easy method to raise alkalinity (which also makes coffee taste better, in addition to some anti-corrosion effect… which BTW isn’t always present, depending on temperatures and pressures).

It’s not necessarily complicated, but there are a lot of factors interplaying, and many are personal choices. In addition to the matter of “coffee taste”, there are significantly different opinions on what is a safe or acceptable amount of “corrosive” compounds (chlorides, sulphates, etc.), or a tolerable amount of/time to (de)scaling.

CoyoteOldMan Thanks for clarifying that technical aspect re acidity. Is the fact that pure standing water is absorbing carbon dioxide the reason you often hear people say to only use water on demand as needed rather than leave large amounts in the espresso water tank? Also is there a simple formula to work out how much bicarbonate of soda to add if using pure water to bring the ph neutral or thereabouts? How do you measure very small amounts of bicarbonate of soda as I would assume you are talking about less than a gram a time?

coffeealex the reason you often hear people say to only use water on demand as needed rather than leave large amounts in the espresso water tank?

I think the reason people are worried about that is more to with biological contamination. RO/DI water does not contain chlorine, which tap water does…

coffeealex Also is there a simple formula to work out how much bicarbonate of soda to add if using pure water to bring the ph neutral or thereabouts?

A buffer is not a neutralising agent. https://en.wikipedia.org/wiki/Buffer_solution

coffeealex How do you measure very small amounts of bicarbonate of soda as I would assume you are talking about less than a gram a time?

Indeed. Which is why many people (me included) use concentrate saline solution. I, for example, use 1.60 grams of KHCO₃ to 400 ml of water to make my concentrate, and then use 20 ml of this solution in 980 grams/ml of pure water, which gets me 80 mg/l of bicarbonate (equivalent to a KH of 40 mg/l of CaCO₃). Otherwise, buy a mg resolution scale (they are cheap nowadays), and spend a bit of time with a pair of tweezers every time you need to mix a litre…

CoyoteOldMan - 🤣🤣🤣🤣🤣

I’ll just leave this here:

Been there, done that. The concentrate route is sooooo much easier! 🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣

coffeealex It seems like you’re confusing terms alkalinity and alkaline. Alkalinity refers to buffering capacity or ability to neutralise acids and maintain a stable pH. Pure water will have a neutral pH of 7. As already covered, how much bicarb to add depends on the alkalinity you want and the amount of water you are treating.

CoyoteOldMan I, for example, use 1.60 grams of KHCO3 to 400 ml of water to make my concentrate, and then use 20 ml of this solution in 980 grams/ml of pure water, which gets me 80 mg/l of bicarbonate (equivalent to a KH of 40 mg/l of CaCO3).

Could i do the same mix on pure RO water? Does the saline solution Keep?

Rob1 You are right I was confusing the two. still on my journey of learning.