My workflow of feeding the machine and keeping the scaling risk is good. I haven’t seen anything, which is a cause for concern, so far. Touch wood. **The current practice:** Feed the remineralised water straight from the OZ on demand; draw a cup after every steaming and do a full refresh every 3 months. Over 14 months, the GH range of the service boiler is 7 mg/l - 21 mg/l. I do think from time to time the following, when the Evo tank requires a refill, if I should do the following once a week: * Remove the mineralisation filter, * draw out the 1L water from the OZ Internal filter * Prep a concentrate of bicarb * Refill the Evo tank and add 8-10ml of concentrate * Draw another 5L of RO and keep it under the sink. We are probably ok during winter. I don’t think we need more than 7.5L a week of RO even if we draw a small cup after every steam. The question: Will the 5L water, if kept at the room temperature, be fit for consumption? Are there any health risks? My wife thinks it is a bad idea, and asked why change the routine when things seem under control; she recommends keeping it simple and continue the current practice, unless required. She does have a point.

This is way overthinking things. **If David had put a borescope inside his steam boiler, I don't think you would see any scale formation.** Osmio is meant to have a cartridge in the remineralisation area, just check the water path of the cartridge. Use a blank one or sterilise an old one and keep using till it wears out. However, I don't believe you need to keep removing the remineralisation cartridge, which also means removing and refitting the filters each time.

> @"DavecUK"#p25502 This is way overthinking things. While you have maintained the decorum, my wife gave me a cold stare and rolled her eyes suggesting ![Giphy - Kate Hudson GIF by The Roku Channel](https://media3.giphy.com/media/H2pGvZcbk7uXzPbGM8/giphy.gif?cid=bb77869ftre5gzo4u67ha77itm824yzieyzxttaq2763vkwx&rid=giphy.gif&ct=g) > @"DavecUK"#p25502 boroscope inside his steam boiler, I don’t think you would see any scale formation. Seriously? Is it because the scale would have formed and coated around the boiler like a thin film?

I spoke to OZ today. During the course of the chat, we spoke about the composition of the mineralisation cartridge. They drew my attention to a few things that can make up the final hardness of the mineralised RO from the OZ. * Feeding hot water, depending on how hard the water is, might have a higher hardness in the pure RO vs the RO hardness from soft/softened water. * A lack of descaling of the RO system will have an impact on the hardness content of the RO water * The silver-costed **mineralisation cartridge has calcium and magnesium** and is likely to add about 10-20 ppm as CaCO3 to the RO water. This depends on how long the minerals were in contact with the water. * If anyone wants to run the unit without the mineral cartridge, it can be done after replacing it with a blank cartridge. Otherwise, the unit will leak. So, it does make sense to test, from time to time, the mineralised RO water from Osmio Zero to get an idea of the general hardness. Feeding a hard water may have a higher hardness content than the soft / softened water. The risk of scaling also differs in every one of our machines.

@"LMSC"#p25507 I think what Dave meant, was that there would be no scale inside the boiler. Simply because there is scale on the outside, signifies that the leak has dripped away and evaporated for a considerable amount of time leaving the deposits that you see. I do not know for sure, but I think Osmio designed the Zero work without changing filters and remineralising on a regular basis. I have ordered one of those measuring things but I am pretty confident the scale build up is nothing to do with the Osmio underperforming!

> @"dfk41"#p25532 I have ordered one of those measuring things but I am pretty confident the scale build up is nothing to do with the Osmio underperforming! I am also sure it isn’t anything to do with OZ. It’s a build over time as you say. In addition, we also know regular steaming and a lack of regular flushing / refreshing will accumulate minerals. 😊

@"LMSC"#p25538 On the outside of the boiler though?

@"dfk41"#p25549 Good question mate! It’s the issue surrounding the inlet complicates it. Did the water leak outside at the L joint around the inlet or the water leak inside out (when it boils) or both? I would think it is inside out - more hardness deposits as we steamed and not flushed. The bottom line is - you are good now. With regular flushing, either a cup a day as some of us do or full monthly flush as MRS suggested should do. Only thing is our first two batches of machines’ pipe does not go all the way down to allow a full flesh thru’ the hot water tap. You may ask Systemic’s routine to ascertain the best way to manage as I have also installed a drain valve.

While this is hot, I thought I’d ask something I’ve wondered about for a while. I only use osmio zero with re mineralisation cartridge. I hardly ever steam, maybe once every two weeks or less (I do intend to get more into it though!). I have refreshed the steam boiler water two or three times since getting the Vesuvius about 6 months ago just as a precaution for stale water purposes. Yesterday I removed the remineralisation cartridge, emptied the osmio tank, and refilled the Vesuvius with just ro water after flushing the steam boiler tank out. I will continue using remineralised water as usual from here. Couple of questions: 1. How often should I refresh this water 2. How often does the osmio remineralisation cartridge last Cheers

@"JahLaza"#p25559 Dave has been using RO for more than 10-12 years. He has plenty of actual usage experience than any of us. I am sure, he will advise you. IMO, your refresh cycle is more than sufficient; Re-the mineralisation filter, it should starts losing its’ potency steadily. It depends on how much water you draw from the unit. We draw at least 10-12 litres a day and more during week ends. Ours’ loses its utility in 6 months. Ex: the TDS when we changed the filter in March was 50-60+. Now, it is about 30! However, we won’t change until it shows change filter or the anniversary month in Feb/March Hope it helps. Don’t think it does anything significant.

@"LMSC"#p25564 thanks for that. I use the osmio with remineralisation as my water source. I assumed that was fine and would not cause scaling even if I steamed every day, assuming an approximate alkalinity of 40mg/l and gh around that too. Don’t want to start another one of these conversations here now!! But, in simple terms I figured remineralised osmio will be fine- plug and play. I also figured I’ve less to worry about seeing as I steam so seldom. I guess that thought was challenged when I saw @"dfk41"#4’s photo here but even that isn’t clear cut as noted by @"DavecUK"#1 that the boiler is probably fine inside. I changed my filters last November and intend to leave alone until I get a warning light to change them or around November seeing as a year has been suggested as a good time to change them if they last that long (I noticed it was stated here before that from a bacterial point of view that’s recommended). That prompted my question about the lifespan of the remin cartridge but don’t think it will be an issue if it’s done before the others either way. I sterilise it with blank cartridges (and Milton tablets) about half yearly. I’m still very pleased with the osmio and am curious to see if I get the year from the filters, my tap water is about 220 mg/l gh I think

Keep the Osmio Zero water (without mineralisation)

JahLaza

coffeealex that’s why I was liking this thread here for a more ‘easy’ to understand for people, just want to hear what’s needed/risky in simple terms coz the detail can get so crazy with the water topic. And thanks to all who have advised here

coffeealex

For anyone interested in the use of an endoscope as mentioned in my previous post these were the camera results from in the past before and after descaling my izzo at a time that I was using only water from a jug with filter not Zero water I should add. Proof that getting the water quality right DOES matter!

CoyoteOldMan

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.

coffeealex

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?

CoyoteOldMan

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…

Rob1

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.

MediumRoastSteam

CoyoteOldMan - 🤣🤣🤣🤣🤣

I’ll just leave this here:

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

coffeealex

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?

coffeealex

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

CoyoteOldMan

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

No (theoretical) difference. Some people find a difference in flavour between demineralised water through RO, de-ionisation or distillation.

The saline solution keeps fine in a closed bottle in the fridge (1 month +) - nothing to spoil… and difficult for algae/bacteria/fungi/protists that accidentally fall into it to multiply in the cold and dark without nutrients.

coffeealex

CoyoteOldMan In trying to keep this simple would this scenario work : Lets assume I have a starting point of 0 tds ( I have removed all minerals etc say with zero water) At this point i have scaling under control but corrosion/ taste could be a problem. So I add bicarbonate of soda at 80mg per litre. Now I have both scaling and corrosion in check as I have added an alkalinity buffer to stop the ph becoming too acidic. Surely this would work? At this point is flushing of the service boiler still required as mineral content is very low meaning scaling is unlikely?

MediumRoastSteam

CoyoteOldMan The saline solution keeps fine in a closed bottle in the fridge (1 month +) - nothing to spoil

I keep my concentrate in a cool, dark place, but not the fridge. There’s no smell or anything after two months. I however use distilled water so any organic form is boiled to death anyway.

MediumRoastSteam

coffeealex - adding 80mg/L of sodium bicarbonate works. This will prevent corrosion, as NaHCO3 will act as a buffer. In addition, it won’t scale, as it does not contain magnesium or calcium in its formula.

And yes, you still need to refresh your service boiler periodically, by drawing a mug of water weekly and/or a full refresh every 6 weeks or so, check TDS to keep tabs on it. Like any dissolved solids, it will be left behind in the boiler as you draw steam out, which is pure (distilled) water.

CoyoteOldMan

coffeealex “Mineral content” (TDS or dry residue) and “probability of scaling” are not the same thing. You could add a lot of sugar to water (more than the weight of water!), and it wouldn’t scale at 130 °C. Heck, you could add quite a lot of copper sulphate, and it wouldn’t scale.

For scale to form you need Ca and/or Mg and (bi)carbonate (or sulphate, but far less likely) ions in solution. If you only add bicarbonate of sodium or potassium, there is no Ca or Mg, so scale will not form.

Flushing is still required as at some point, as bicarbonate salts convert to carbonate with heating, and carbonate solutions can be corrosive. Do you need to flush frequently? No, probably once every few months - and that’s largely out of caution.

coffeealex

MediumRoastSteam Thank you, makes total sense

coffeealex

Personally I think as far as Oz is concerned, they should have gone the way of Skuma, by having a choice of mineralised/demineralised water by just pressing a button and not having to use an empty cartridge. Surely a simple bypass of the cartridge in the piping would give that choice. Then if you wanted mineralised water you press one button or demineralised you press another or hold the same for longer.

Or have a two cartridge system. One exclusively for espresso machines by not using magnesium or calcium carbonate and another with the minerals for taste. The best of both worlds

Verion

My Minima is turning up next week and I’m thinking of getting the Osmio Zero to use in the brew and service boilers.

Am I right in thinking that with the Osmio Zero will purify and remineralise my tap water with no other intervention needed, I shouldn’t get any scale?

LMSC

Verion There are many water threads on this forum. Please spend some time reading them. One example is here

https://coffeetime.freeflarum.com/d/1105-accurate-water-testing-kits

My OZ experience:

If you manage by regularly drawing a cup after steaming and a monthly full flush, you should be able to minimise the risk.

Eiffel

Based on my experience with the Evo Leva (same boilers as the Minima), I’d suggest the simple additional step of drawing around a cup of hot water from the service boiler after steaming milk when using the Osmio Zero and the remineralisation cartridge.

I’ve done so for over a year and the TDS of the hot water (after letting it cool down) stays stable at about 55 ppm… and thus I haven’t felt the need for a monthly full flush but YMMV

Verion

@LMSC Eiffel Good tips.

I have no problem in drawing a cup from the service boiler after steaming milk and monthly flushing.

Planet Organic have a good deal on, so I think I’ll make the jump.

@Eiffel How are you testing your TDS?

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