Member's Mark Water Quality

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
blutch

#1: Post by blutch »

You can get 4 gallon water bottles at Sam's Club labeled Member's Mark Purified Water. Anyone know if this water is appropriate for my espresso machine and won't do damage as is?

B

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homeburrero
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#2: Post by homeburrero »

blutch wrote:You can get 4 gallon water bottles at Sam's Club labeled Member's Mark Purified Water. Anyone know if this water is appropriate for my espresso machine and won't do damage as is?
They are very careful not to say anything specific about the added minerals in this water, other than it being RO with a small amount of calcium chloride and sodium bicarbonate added for taste. That lack of transparency is enough, for me, to avoid buying it. The chloride is not an ideal choice for espresso machines (any chloride may be corrosive) but probably is a tiny amount. This water is reportedly (per untrustworthy sources on the internet) only around 20 - 30 ppm TDS and slightly below 7 pH. If so, it would not cause scale problems but may be a little corrosive.
Pat
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blutch (original poster)

#3: Post by blutch (original poster) » replying to homeburrero »

Thank you. My machine has copper boilers. I know that lime scale is bad, but I'm not up on the issue of corrosion. I thought calcium buildup and scale were the same thing.. can you clarify? Is it the calcium chloride I should also be avoiding? I'd like to find a consistent large quantity source of water for my machine which I am going to plumb in with a flojet system from Caffeworks which is on its way. I want to be rest assured that my water isn't hurting my new machine. thanks!

B

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homeburrero
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#4: Post by homeburrero »

blutch wrote:I thought calcium buildup and scale were the same thing.. can you clarify?
Limescale is calcium carbonate, and is the usual problem that needs to be dealt with via softening, descaling, or using scale free water. There are other deposits that many people also refer to as scale - one is calcium sulfate (gypsum) that can be dealt with by softening or keeping the calcium concentration low. At the low concentration of calcium that I suspect is in that Members Mark water, scale would not be an issue.


blutch wrote:Is it the calcium chloride I should also be avoiding?
In this case the problem is really the chloride ion rather than the calcium. Chloride ion can be corrosive, especially if the alkalinity and pH are low. If the chloride ion is not too high (below 15 mg/L or so) it may not be worth worrying about, but I think it's worth looking around for a water that doesn't have any chloride added.


blutch wrote:I'd like to find a consistent large quantity source of water for my machine which I am going to plumb in with a flojet system from Caffeworks which is on its way.
If this is the best you can come up with I think you could get by with it if you:
1) Verify with a TDS meter that the water is indeed low mineral, showing ~ 30ppm or less on the TDS meter.
2) Bump the alkalinity up by adding bicarbonate. About 0.3 gram potassium bicarbonate per gallon would increase the alkalinity of the water by around 40 mg/L . (Most advice is that you want 40 mg/L or more alkalinity for espresso machine water.)
This should be non-scaling and reasonably non-corrosive.

* Note: Guessing about possible chloride in this water: If the water reads 30 ppm TDS or less and it contains a mix of sodium bicarb and calcium chloride it's probably reasonable to guess that it has less than 20 ppm calcium chloride (CaCl2), which would mean that it would have less than ~ 13 mg/L chloride ion. I wish the bottler of this water provided real numbers so we would not have to assume and guess. (Even Nestle provides analysis results for their drinking waters.)
Pat
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blutch (original poster)

#5: Post by blutch (original poster) »

PAT - I'm so grateful for your help with this. I really don't know what I'm doing, but I have more information. I tested the Member Mark water and the RO water available from the refill station in the grocery store near me. The TDS of the RO water was 9ppm and the TDS of the MM water was 11ppm.

I also used test trips to test for other things. Please tell me what you think... Am I "safe" from scale and corrosion with these and do I need to add Rpavlis concentrate to either or both these waters?

Here's the strip for the RO water:



Here is the Member Mark Water test:


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homeburrero
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#6: Post by homeburrero »

blutch wrote:I tested the Member Mark water and the RO water available from the refill station in the grocery store near me. The TDS of the RO water was 9ppm and the TDS of the MM water was 11ppm.
That implies that they are adding only a tiny amount of minerals to that MM water, so it should be fine to use as a base for rpavlis or similar water. Both of these really need the added bicarbonate for machine health. Also those ppm levels are so low that without the added minerals, your machine's water level sensors might not work.
Pat
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blutch (original poster)

#7: Post by blutch (original poster) » replying to homeburrero »

Thank you Pat. How about the PH and Alkalinity? Is there any corrosion risk?

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homeburrero
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#8: Post by homeburrero »

blutch wrote:How about the PH and Alkalinity? Is there any corrosion risk?
The pH and the alkalinity of water with this very low TDS are going to be low. So you want to add enough bicarbonate to fix that. The rpavlis recipe, 0.1 gram of potassium bicarbonate per liter of water, would give you 50 mg/L alkalinity and a non-acidic pH -- it would not be corrosive.
Pat
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blutch (original poster)

#9: Post by blutch (original poster) »

Pat, can you check my math? My plan is to mix Rpavlis water concentrate into a 1 gallon bottle of distilled and use that to charge my bottle serving the espresso machine. The recipe calls for 8.5 gr of baking soda per liter. I take that times 3.785 to convert for a gallon and I get 32.17 grams per gallon.

Then I mix 30ML of concentrate per gallon of my base water whether it is distilled, RO from the grocery store or Member's Mark or even Ozark drinking water. I will most likely charge 5 gallons of water at a time which equals 150MLs of concentrate. Does that sound right? I do have some liter bottles to use for the concentrate, but gallon jugs are much more accessible.

I hope this will give me consistency and protect my equipment. Thanks again for all your help.

B

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homeburrero
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#10: Post by homeburrero »

blutch wrote:Pat, can you check my math
Looks right for bumping up whatever alkalinity level that you have in that water by 40 mg/L CaCO3 equivalent, which is reasonable.
Pat
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