No Sulfate

[snowtiger1987]

I just completed a test of my brewing water with the LaMotte Labs kit and while the results seem reliable, the one thing that stood out is that the test results said my water had no Sulfate at all. Is that possible? likely?

I looked at the published municipal water report and it does not list Sulfate or Sulfur at all.

 

[mabrungard]

Its possible. The ionic content of your water is dependent upon what its come into contact with before reaching you. You must not have any sulfurous rock or air in your area.

 

[snowtiger1987]

No volcanoes around here. Just the Rocky Mountains.

Looks like I have to be careful to not add too much Calcium when trying to get my Sulfate up enough to make hoppy beers.

 

[ajdelange]

I had one guy tell me that his well, located but 5 miles or so from mine, showed 0 sulfate in his Ward labs test. Since mine runs about 27 ppm (as SO4--) I had him bring by a sample and we ran the sulfate. 0 (or below the minimum detection level of the test). So it's possible but it is not likely. I believe the Lamotte kit uses the standard BaCl2 + SO4-- -->BaSO4 + 2Cl- chemistry with the precipitate quantified by comparison with a frosted slide. The first step on the slide is, I believe, 20 ppm. It would not surprise me at all that a sulfate level of 5 or less would be dismissed if reading the turbidity in this way. With a nephelometer or photometer you might well detect sulfate at such lower levels. The fact that your municipality does not report it does, however, suggest that it is low. But even rain water contains some sulfate.

 

[chris000]

Comparing wells really depends where you live. For example, in the shield, direct neighbors can have vastly different water and in other areas you'll find pretty much the same for the entire county.
I don't know how your municipality tests, but if they use the classical gravimetric method in which sulfate is precipitated as barium sulfate, the limit of quantitation would be around 10 mg/l. Perhaps yours is below, but still they should list the parameter and N/A, LOD or LOQ.
By the way rain has anywhere between 1 and 10mg/l (depends how industrialized the area is you live in)

 

[ajdelange]

Not sure whether you are responding to OP or me in No. 5 (or perhaps both of us) as we both mentioned 0 sulfate but I mentioned comparing near by wells and you discuss that. In neither case was testing by the municipality but in OP's case by a Lamotte kit. In my testing I use Hach Sulfaver (BaCl2 with excipients that help keep the precipitate in suspension). The test is described as being suitable from 2 - 70 ppm and its sensitivity is 0.4 ppm/0.010 Abs so at the lower limit we'd have A = 0.050. Thus, when my friend's well read A = 0.000 I was pretty confident that there wasn't much sulfate in it.

I did mention in No. 4 that the precision of the LaMotte kit is pretty rough so that OP might well not detect 5 - 10 ppm with that technology.

Also, and I'm relying on memory here, I measured 3 ppm (using Sulfaver) in the rainwater of rural Quebec ( a neighbor there, a real tree hugger, had installed a rainwater collection system and was concerned about acid rain - bird poop, no, but acid rain, yes). If I was smart I would have evaporated the volume down considerably to improve the sensitivity of the test but I really don't remember whether I did or not.

 

[chris000]

ajdelange, you way more up-to-date on the testing than I'm
3ppm for rural area sounds about right.
barite, gypsum and a magnesium sulfate hydrate (can't remember what that's been called again) are the typical mineral contributors. don't think smelters are a big topic anymore and besides they only impacted rain some surface water.
below 10ppm (or less according to your post) is background/method. so, I wonder why they would not mention it in any form (e.g. <10ppm, ND, etc.) - just feel about the same as the OP why it is not mentioned.

 

[ajdelange]

barite,

This is very insoluble. A saturated solution would only contribute 1.2 mg/L SO4--.

gypsum

Though not that soluble this is the major contributor (AFAIK) to the point where high sulfate waters are often referred to as being 'gypseous'.

and a magnesium sulfate hydrate (can't remember what that's been called again)

Epsom salt.
This and sodium sulfate (glaubers salt, mirabilite) may be high sulfate contributors in some areas.

don't think smelters are a big topic anymore and besides they only impacted rain some surface water.

I believe most of it comes from the oxidation of SO2 which in turn is largely the product of combustion of sulfur containing coal, fuel oil and gasoline though a lot comes from volcanic eruptions (alarmists: ignore last source).

I wonder why they would not mention it in any form (e.g. <10ppm, ND, etc.) - just feel about the same as the OP why it is not mentioned.

I haven't seen his report but where an ion is present in minimal or below detectable concentration authorities often don't bother to report it. Or may omit it in the high level report that goes to the consumer while mentioning it in their more detailed reports.

 

[Sauls]

Image

• Sauls
• Feb 4, 2018

Sulfate test

Looking for a little help on my sulfate test. With the Brewlab reference color card, black is 0ppm, and the lightest gray is 200ppm. Well my tests show 0 color change - stays clear. I’ve followed the directions and cut the sample with distilled water but this is where I’m confused. Do I start over agin with clean sample water, 5ml of distilled, mix, and dump out 5ml and drop another turb tablet? Still 0 color change, could I be above 400ppm? Or do I cut the previously used sample? Pic attached is probably easier to follow than my rambling.

 

[ajdelange]

You want to concentrate the sulfate in your sample - not dilute it. Take a liter of water and boil it town to 50 cc. This will concentrate the sulfate 20 times.

 

[Sauls]

That makes sense to boil, is it just me or are the directions confusing? “More turbid than 200 follow the dilution.” Also with this test kit the color card is in increments of 50s, not sure how I would be able to come up with a ppm using your concentration method.

 

[ajdelange]

Everything is kosher. If the test showed greater turbidity than the maximum on the provided scale clearly the sulfate exceeds the maximum level the test can handle so you dilute the sample until it is in range.

I suggested concentrating by a factor of 20. Thus if you 'read' 50, the concentration was 50/20 = 2.5. If you read 100 the concentration was 100/20 = 5...

 

[Sauls]

Ok ajdelange, please forgive me for being confused, but I boiled down a splash of water to a 5mm and sure enough I got a reading of 150. I believe in the metric system but being a hard headed Ronald Reagan fan I can’t figure out a smaller sample, and then how do I covert that to this insane sample card? My local report shows 100 ppm and I’m almost ready to give up and go with that. Much appreciated

 

[ajdelange]

You are going to have to be a bit more precise in your quantity determination than 'splash' if you hope to get this to work. Start with a liter of water. Boil it down to 50 mL. Cool it. As the total sulfate is the same before and after boiling but the volume is now 1/20th of what it was the concentration of sulfate is now 20 times what it was at the start. If the scale reading is 150 mg/L now the original concentration must have been 1/20th of that i.e. 150/20 = 7.5 mg/L. I can think of no way to make it any clearer. If you still can't follow try showing this to a brewing friend who, while perhaps he cannot explain it, should at least be able to give you the answer.