Concern about high chloride water

[sei1]

Hi, this is my first post and I just want to thank everyone for all of the helpful discussion in these forums as just reading through these posts the previous few months has greatly improved my knowledge and understanding of all that goes into espresso.

For the topic of the post, I have some concerns about the water I have been using in my machine and hope to get some advice on if my concerns are warranted and what to do going forward.

I recently received a new stainless steel double boiler machine about two months ago (Lucca M58). I tried to inform myself beforehand about what type of water treatment would be best. I could not find any detailed water information from my water utility, but I used some water hardness test strips which estimated my hardness around 100-150 ppm. I ended up deciding to use a BWT M in tank pouch and Brita pitcher filtered tap water with the goal of reducing/preventing any scale buildup.

Out of curiosity, I decided to submit my water to a lab (used tapscore.com) last week to get a better understanding of my overall tap water quality and to see how the filter/pouch combination was working on my water. Based on the lab test results and my understanding from these forums, my results show fairly high chloride levels and the potential to become corrosive following the filter/pouch treatment which greatly reduced the alkalinity and made the water very acidic. Based on the results, it looks like calcium is low enough that scaling might actually not have been an issue. However, there is high chloride which would be a concern. I'm thinking I should immediately switch to one of the recommended bottled spring waters in the short term and then eventually start making my own water. In hindsight, I probably should have started with bottled in the first place since I didn't have a complete picture of my water.

My questions for this post are how worried should I be about potential corrosion damage caused to the machine in the past two months? Is it enough of a concern that I should open it up and check for damage? Are there any health concerns that I should be aware of from any potential corrosion?

One other thing I thought was weird, is that the results from the filtered/treated water also showed a very large reduction in Magnesium. My understanding is that the BWT pouch is supposed to exchange Calcium ions for Magnesium, but it seems both were greatly reduced which led to a large reduction in alkalinity.

Here are the relevant results from the water test. Let me know if there is any other information that would be useful. Thanks in advance for any answers.

Water test results
Tap (prefiltered)
Calcium: 28.24 mg/L
Magnesium: 7.86 mg/L
Sodium: 23.76 mg/L
Alkalinity (as CaCO3): 50 mg/L
Total Hardness: 102.9 mg/L
pH: 7.34
Chloride: 49.5 mg/L

Filtered and treated (Brita filter and then BWT M Pouch)
Calcium: 1.64 mg/L
Magnesium: 2.2 mg/L
Sodium: 8.9 mg/L
Alkalinity (as CaCO3): 0 mg/L
Total Hardness: 13.2 mg/L
pH: 5
Chloride: 48 mg/L

[Pressino]

Your chloride level is not super high, but high enough to use either RO + remineralization if your machine is plumbed in, or just use the reservoir w ith appropriate water. The chloride situation gets worse, as you mentioned, with the drop in pH from 7.35 to 5.0 after filtration. My vote is for using the reservoir as the easiest solution.

[homeburrero]

Thanks for this report - nice to see some hard data and very instructive in pointing out an instance where a WAC filter (like the BWT Bestsave pouch) is a poor choice.

In this case your water would probably scale a little due to the high calcium (about 70 mg/L as CaCO3) and the 50 mg/L alkalinity. (The LSI on that at at 1 bar, 120C is just over +0.5, indicating light scale deposition. )

After treating with that BestSave pouch you certainly have solved the scale risk issue, but you also have low pH and near zero alkalinity. The chloride, of course, stayed the same so your combination of acidity and chloride caused a water situation with high corrosion risk. For sure, ditch the bestsave pouch for use with with this water. With water where hardness is high and alkalinity is moderate you are usually much better off with a conventional softening pouch like the Rocket/OsCaR/Bilt -- it reduces hardness but not alkalinity, and does not acidify the water.

Given your high chloride I agree with Pressino - use bottled or recipe water. If you really want to plumb-in you can either use the carboy/flojet approach with bottled or recipe water, or go with and RO and remin cartridge. Just get the water right moving forward -- I don't think you need to worry about or try to remedy effects of corrosion that may have already happened.

One other thing I thought was weird, is that the results from the filtered/treated water also showed a very large reduction in Magnesium. My understanding is that the BWT pouch is supposed to exchange Calcium ions for Magnesium, but it seems both were greatly reduced which led to a large reduction in alkalinity.

The BWT patented technology here is just a WAC resin that is loaded mostly with the usual H+ ions and partly with Mg++ ions. So it usually exchanges a Mg++ ion or a Ca++ ion with two H+ ions, and sometimes exchanges a Ca++ ion with a Mg++ ion. As your case demonstrates, the relative balance between Ca and Mg shifts toward Mg, and both may be reduced. The released H+ ions are buffered by bicarbonate and that reduces the alkalinity and acidifies the water as you observed.

[sei1 (original poster)]

Thank you both for the feedback and the reassurance. After doing more digging into chloride levels, I think Pressino is right that it is not on the super high side. It was really the sharp decrease in pH that got me so concerned and that in combination with the chloride levels...so hopefully 2 months wasn't long enough to cause any significant issues.

I'll have to do more digging into the chemistry of corrosion from chloride, but it seems to me like this was a lesser discussed issue when I was trying to do my initial research into water. It's only now that I'm specifically using search terms including WAC/chloride/acidic etc that I'm finding discussions on it. Not to throw any shade, but as far as I can tell looking back at information from the manufacturer or merchants of the BWT packet and similar WAC resins there isn't any warning about what situations in which it may not be the best choice--just that its a simple way to reduce the chance of scale. The larger focus on a lot of articles about espresso water is on scale and looking back at those articles I read, none mention chloride or corrosion. It also seems like a lot of espresso machines come with a hardness test strip with the implication that that's the only factor to consider.

[sei1 (original poster)]

I've ordered some potassium bicarbonate and glass bottles/jugs to be able to start making my own water from distilled.

In the meantime, I found a bottled spring water at my local grocery store that seems pretty good. Best I can tell comes from only one source and has fairly low hardness and chloride (https://foxledge.com/wp-content/uploads ... P-2021.pdf). I was thinking I may add a small amount of baking soda to increase the alkalinity closer to 50 mg/mL. Any feedback would be appreciated.

From the above linked water report:
Calcium: 27 mg/L
Magnesium: .79 mg/L
Sodium: 1.6 mg/L
Alkalinity: 26 mg/L
Total Hardness: 31 mg/L
pH: 6.9
Chloride: .72 mg/L

[homeburrero]

I found a bottled spring water at my local grocery store that seems pretty good. Best I can tell comes from only one source and has fairly low hardness and chloride (https://foxledge.com/wp-content/uploads ... P-2021.pdf). I was thinking I may add a small amount of baking soda to increase the alkalinity closer to 50 mg/mL. Any feedback would be appreciated.

From the above linked water report:
Calcium: 27 mg/L
Magnesium: .79 mg/L
Sodium: 1.6 mg/L
Alkalinity: 26 mg/L
Total Hardness: 31 mg/L
pH: 6.9
Chloride: .72 mg/L

Nice Find! That looks like good choice - it's a little on the soft side, softer even than the Crystal Geyser Mt Shasta water. But usable as-is, would be similar to Seattle water. Note that the calcium number is actually calcium hardness (as CaCO3) of only 27 mg./L. So you could bump the alkalinity up by adding a little bicarbonate and it would still be non-scaling. It would not hurt to add about 0.2 gram of potassium bicarbonate per gallon of this water to bump up the alkalinity by another 26 mg/L as CaCO3, getting you into the 50 mg/L ballpark. That would also bring the pH up above neutral.




P.S.
Related to your researching WAC/chloride/acidic issues, I thought it may be useful to add some links here. I think the OP has already seen these, but may be useful to others that find this post when looking into high chloride water issues.

It is true that BWT and most water treatment suppliers don't say much about the chloride corrosion issue. A while back some folks at Pentair did share some helpful info with us about chloride and WAC (decarbonizing) softeners with respect to stainless corrosion in this article: /downloads/ ... pdated.pdf

Even the SCAA, as well as the newer SCA water quality handbooks say very little about chloride corrosion risk. Until La Marzocco sounded the alarm about their experiences with boiler failures in Cambridge MA, I think very few people were aware of the chloride issue with espresso machine corrosion. ( Scott Guglielmino from La Marzocco a few years back on high chlorides: "The city of Cambridge was able to do more damage to our boilers than the rest of the United States combined."
See http://www.youtube.com/watch?v=dPmcF-b-gRQ, at about 21:40.)
Cambridge MA has had very high chloride for many years, often well above 150 mg/L.



Here on HB we had a chemistry professor, Robert Pavlis (rpavlis) who was very knowledgeable about chloride corrosion, especially in copper and brass who shared lots of info about that:
Elektra Microcasa a Leva boiler leak problem
La Pavoni Europiccola Boiler Leak
High pH in the boiler water, help please (I included this only because it's a case where Dr Pavlis was not especially concerned about chloride ion numbers of around 20 mg/L in a water with good alkalinity and pH.)


Two big chloride threads on HB
Chloride in Water - Recommended Acceptable Ranges
Boiler-safe level of chlorides (and other compounds) in water

And a long thread about chloride levels and WAC (decarbonizing) softeners
Warning: Chloride & sulfate levels with weak acid cation softeners (e.g., Everpure Claris)

[sei1 (original poster)]

Thank you for the additional links, a couple of those are threads I hadn't found yet.

It is true that BWT and most water treatment suppliers don't say much about the chloride corrosion issue. A while back some folks at Pentair did share some helpful info with us about chloride and WAC (decarbonizing) softeners with respect to stainless corrosion in this article: /downloads/ ... pdated.pdf

Those slides are interesting, but without the context I'm having a hard time interpreting the severity of potential corrosion issues. The water reports they show before and after the WAC have chloride levels of 250+ mg/L. And similar to my experience had very low pH after treatment. But at the end they say below 80 mg/L is recommended.

From all of these threads though, the best practice seems to be avoid to chloride completely. Those pictures showing corrosion issues in the refurbished parts make me glad I realized this after only two months!