PLEASE NOTE: I am not a chemist and I find it difficult to digest all the «water for coffee» information here on HB.

Hi fellow coffee nerds! I need your help.

I bought a new machine 3-4months ago (ECM synchronika w/ flow control) and I decided that I wanted to make my own water from the start. My recipe was based on the Rao recipe: *note that minerals were directly added to 5gal => direct dosing*
- Volume: 5gal / 18.9L
- Epsom salt: 3.51g
- Sodium Bicarbonate: 1.59g
-TDS: 174, high sulfate (>50mg/L)



When I removed the E61 mushroom, I noticed this (see photo) on the E61 brass actuator. This seems like an incredible amount of scale/deposit for a 3-4months old machine. No significant build up was found on the mushroom (stainless steel), so I assume my boilers are OK




I changed my recipe straight away for this one (photo below) after contacting Jonathan Gagné from Coffee ad Astra:
- Volume: 5gal / 18.9L
- Epsom salt: 2.81g
- Sodium Bicarbonate: 1.06g
- Calcium chloride (CaCl2) anydrous: 0.41g or 0.54g if it's calcius chloride dihydrous




Any advice on what I did wrong? I admit that I have not been flushing the steam boiler regularly. Maybe too high sulfate or TDS = corrosion/build up?

It's hard to tell but that looks like a thin blue-green coating, which would indicate corrosion of the brass. I would not expect your original recipe to cause corrosion problems. It does have 70+ sulfate, but given the alkalinity should not be a corrosion issue. Note that the TWW espresso formula has over 100 mg/L sulfate, along with lower bicarbonate, and people don't seem to be seeing corrosion effects. Corrosion is complex, and maybe yours is is related to aggressive water used in a QA test of the new machine followed by a long dry spell on the shelf. I'd suggest cleaning those valves and watching them going forward. Ideally they'll develop a dull dark protective oxide coating over time.

Dimon Soyon wrote:I changed my recipe straight away for this one (photo below) after contacting Jonathan Gagné from Coffee ad Astra:
- Volume: 5gal / 18.9L
- Epsom salt: 2.81g
- Sodium Bicarbonate: 1.06g
- Calcium chloride (CaCl2) anydrous: 0.41g or 0.54g if it's calcius chloride dihydrous

Now that's unquestionably a move in the wrong direction if you want less corrosion. It has less alkalinity than your original water, and is slightly below the usual recommendation of 40 mg/L or more alkalinity for corrosion protection reasons.

But far more worrisome is that chloride. Any chloride may be corrosive, especially to copper and brass and especially if alkalinity is low. At 26 mg/L of chloride ion it's barely within the La Marzocco recommendation of 30 mg/L or less, but well above the Synesso recommendations of 5-15 mg/L or less.

When making water for use in espresso machines I'd recommend just steering clear of any chloride salts. I've generally followed the advice of Robert Pavlis with respect to corrosion and espresso machines -- Dr Pavlis was a professor of chemistry and expert in copper/brass corrosion, HB member name rpavlis, who passed away a few years ago. He was adamant about avoiding any chloride, and debunked the old idea of 'protective calcium carbonate scale'.

Many people on HB use his recipe of 100 mg/L potassium bicarbonate to get 50 mg/L alkalinity, zero hardness minerals, zero chloride, and zero sulfate. You could meet his recipe partway by using your original recipe, trying it with no Epsom salt, and maybe trying again with about half as much Epsom salt as your initial recipe. If adding the Epsom does not make it taste better then just don't use it.

Pat is the expert on water. I am not an expert on water, but I have learned a lot from him and this forum. To make your own water, you could use 1.9 grams of potassium bicarbonate to 5 gallons of distilled water. Or you could use 0.4 grams of potassium bicarbonate to 1 gallon of distilled water. From what I have learned from this forum and Pat, one would not have to descale your espresso machine if you used this water(rpavlis water). I am considering purchasing an ECM Synchronika(your machine) and want to be certain from the start to use the best water I can. I contacted WLL and they also said that this water formulation would be good for the Synchronika and should not require descaling. Although, from your picture, your problem looks potentially serious, it is good you caught it early.

I was hoping the famous «homeburrero» would reply

bobkat wrote:To make your own water, you could use 1.9 grams of potassium bicarbonate to 5 gallons of distilled water.

That is good to know. I will start with RPavlis water recipe with potassium bicarbonate only and will see if I can taste a difference with my current recipe.

I will avoid chlorides from now on.

I suspect that the distilled water dispencer wasn't well maintained. It seems a little sketchy to me hahaha. I will try to find a better source.

homeburrero wrote: Many people on HB use his recipe of 100 mg/L potassium bicarbonate to get 50 mg/L alkalinity, zero hardness minerals, zero chloride, and zero sulfate. You could meet his recipe partway by using your original recipe, trying it with no Epsom salt, and maybe trying again with about half as much Epsom salt as your initial recipe. If adding the Epsom does not make it taste better then just don't use it.

What water recipe are you using right now?

Any different for stainless steel boilers?

Just to confirm, and apologies if it's a dumb question, but you added these minerals to distilled water, correct?

No question is stupid

Yes! I added these minerals to 5gal distilled water from a dispenser. I ran a sterilization cycle before re-filling the container.

Dimon Soyon wrote:Any different for stainless steel boilers?

My understanding is that copper and brass are more susceptible than stainless to chloride and sulfate related corrosion, but it is a concern for stainless as well.

Dimon Soyon wrote:What water recipe are you using right now?

I described my own recipe in this post: An all carbonate water recipe (cloudy concentrate, no sodastream)

I'm still using that one, which for me is very easy to mix. Like rpavlis water it has no chloride and no sulfate, and good alkalinity. But I don't generally advocate it for others. It's no better for machine health than the simple rpavlis recipe and I can't say that it tastes any better.

Thanks!

I will try the potassium bicarb recipe in distilled water first. I will report data (or damage... ) or the second water recipe. I only went through half of it (2.5gal) in about 2-3 weeks. I flush regularly now out of my HWW.

I noticed that the pump makes a weird clicking/thumping noise after refilling the steam boiler right after the flush. I did not opened the chassis of the machine since I got it (ECM Synchronika). Pump cavitation? Loose screws?

Dimon Soyon wrote:I noticed that the pump makes a weird clicking/thumping noise after refilling the steam boiler right after the flush.

I think that's just the sound of the heater responding to the cool refill water that was added to the boiler.