Boiling to lower alkalinity

(That's water to the rest of us!) Beer is about 95% water, so if you want to discuss water treatment, filtering etc this is the place to do it!
Carnot
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Re: Boiling to lower alkalinity

Post by Carnot » Sat Jan 02, 2021 8:03 pm

Eric,

I would agree that the other anions (chloride and sulpahte) will influence the tolerable alkalinity of the water. I was surprised by the concentration of nitrate and sulphate in the analysis of Matt's water. Nitrate is not that common and is often indicative of agricultural run -off. It tends to be consummed fairiy rapidly by plants. I would hazard a guess than this is an example of nitrogen fertilizer run-off.

But the main point is the split of Ca and Mg vs alkalinity. I am having to dig deep into my history. In open evaporative cooling systems, the sort that power stations use, acid dosing to reduce alkalinity is commonplace, if not mandatory. A typical Oxford type water would need significant acid dosing to keep the alkalinity within limits to stop the precipitation of calcium carbonate. Even then we had to use scale inhibitors based on polyphoshate and phoshonates which acted as sequesterants. There were two methods of calcuating the scale precipitation( still used) the Langelier Index and the Ryznar Index( I favoured the latter). These indices essentially calculated the scaling or preciptiation potenial of a water. As the concentation of cations and anions increased then the potential for precipitation increases according to the following algorithims.

https://www.lenntech.com/ro/index/lange ... nation.htm
https://www.lenntech.com/calculators/ry ... ryznar.htm

I do not think that these indices have any significant relevance on brewing liquor, especially the effect of boiling to reduce alkalinity, the subject of this post. But, the reduction isn alkalinity is a function of the ion concentrtion and the thermal decomposition of bicarbonate which lead sto calcium carbonate precipitation which is also influenced by the concentration of chloride and sulphate anions.

Going back to cooling water, alkalinity was the most important influence on scaling. No real surprise. Get the alkaninity down and treat to control the corrosion.

On a purely analytical note it is essntial that the liquor after boing is filtered. The preciptated calcium carbonate can be colloidal and will affect the alkalinity determination. A very fine filter is necessary( and I mean fine < 1 micron).

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Eric
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Re: Boiling to lower alkalinity

Post by Eric » Sat Jan 02, 2021 11:44 pm

Sadly, high nitrate levels are commonplace these days, its continuous increase from artificial fertilisers in this area is happening despite a constant reduction in the amount of land used for agriculture.

You likely have an advantage over me on digging into history, being more than halfway into my eighth decade on this planet, a lot of debris has accumulated since studying marine engineering and steam generation, which as you suggest, has little in common with brewing.

The relationship between calcium and magnesium in water is complicated by varying geology. My water supply comes from magnesian limestone, of which there are many kinds, but mine mostly is dolomite, CaMg(CO3)2. Most would think of limestone as CaCO3, with smaller inclusions of magnesite MgCO3, but it isn't that simple. In brewing, acid always solves the alkalinity problem, while boiling comes with no guarantee. As it is a waste of time and money for me to boil my water, I don't advise others to do so.
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MattGuk
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Re: Boiling to lower alkalinity

Post by MattGuk » Wed Jan 13, 2021 11:05 am

Sorry for the late response, been super busy at work.
Just out of I retest, how did you guys figure out my approximate Calcium from the Magnesium?
Really interested in the equation as it would be helpful.

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Eric
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Re: Boiling to lower alkalinity

Post by Eric » Wed Jan 13, 2021 11:33 am

Eric wrote:
Thu Dec 31, 2020 1:05 am
MattGuk wrote:
Wed Dec 30, 2020 11:12 pm
So, I have an average hardness of 244ppm as CaC03 and and average Alkalinity 152ppm as CaCo3, which is the important factor in that report?
When I measure the Alkalinity with Salifert I take the dKH measurements and Multiply them by 17.85 to get my Alkalinity, I presume as CaCO3 but maybe that is wrong?
Yes Matt, your calculation for alkalinity using the Salifert kit is correct.

Hardness is roughly calcium times 2.5 plus magnesium times 4.1. Calcium is not given in that report, but magnesium is at 5.1 mg/l which gives a calcium level of 89.2 mg/l. That fits well with the other values given including those for sodium, sulphate and chloride in that report, but does question the accuracy of the Salifert kit calcium test.
(Ca * 2.5) + (Mg * 4.1) = Total Hardness as CaCO3

(Ca * 2.5) + (5.1 * 4.1) = 244 (all as mg/L, otherwise ppm)

Ca " 2.5 = 244 -(5.1 * 4.1) = 244 - 29.91 = 223.09

Ca= 223.09/2.5 = 89.236.
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Re: Boiling to lower alkalinity

Post by MattGuk » Wed Jan 13, 2021 11:47 am

Thanks Eric, will try and wrap my head around it.
I know this may sound silly, but Maths is something I REALLY can't do lol

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Re: Boiling to lower alkalinity

Post by MattGuk » Wed Jan 13, 2021 12:31 pm

Just one thing to also mention, there was a question as to how accurate my Salifert Calcium test kit is.
In my instruction it's say to add 10 drops of the CA2 regent, however looking at various YouTube videos, they all say add 10 drops.
Does anybody else use these kits, and if so, how many drops do you use?
I wonder if I am actually supposed to use 8 drops instead of 10.

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Eric
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Re: Boiling to lower alkalinity

Post by Eric » Wed Jan 13, 2021 5:36 pm

I've not used a Salifert kit to determine calcium. Reading these instructions suggest 8 drops, but I wouldn't know what is correct. It is noticeable that the kit is designed to cater for much higher levels of calcium than in your water, although it does cover that range too.

My water's mineral content can vary significantly, so got a series of analyses by Wallybrew. Using those and a TDS meter reading, I can quickly and accurately determine mathematically the mineral contents.
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Re: Boiling to lower alkalinity

Post by MattGuk » Thu Jan 14, 2021 10:42 am

But would a TDS just show me the amount of total dissolved solids or would it help more with knowing the Calcium content?

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Re: Boiling to lower alkalinity

Post by Eric » Thu Jan 14, 2021 12:35 pm

MattGuk wrote:
Thu Jan 14, 2021 10:42 am
But would a TDS just show me the amount of total dissolved solids or would it help more with knowing the Calcium content?
It would do both Matt, not perfectly accurate, but good enough for our purposes. It would let you know how consistent your water is or is not. It is highly likely if the TDS of your supply increases, so will its calcium content.
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Re: Boiling to lower alkalinity

Post by Heron1952 » Thu Jan 14, 2021 3:10 pm

FWIW my water near Carterton, just down the road from Witney, had 99ppm calcium albeit 3 years ago. Time for another Wallybrew test!!!
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Re: Boiling to lower alkalinity

Post by MattGuk » Thu Jan 14, 2021 4:58 pm

I'm from Witney, so I guess our water would be similar?

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Re: Boiling to lower alkalinity

Post by Heron1952 » Fri Jan 15, 2021 12:03 am

MattGuk wrote:
Thu Jan 14, 2021 4:58 pm
I'm from Witney, so I guess our water would be similar?
Probably but only a proper Wallybrew test would tell, Thames water does vary and their publish figure are very average.
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