Can you calculate the effect of boiling on water?

[Bennypapa]

It's well known that boiling has an effect on water chemistry. Co2 is driven off and minerals that were dissolved in the water by the co2 will settle out if I understand it right. The boiled water can be decanted off the top if done promplty.

Is there a way to calculate this effect?

My water

Existing water
Ph 7.8

Ca 41.4
Mg. 9.9
Na 22.3
Bicarb hco3 110
Sulfate 55 S04-s
Chloride 30
Cations 3.8
Anions 3.8
Total hard. 144
Alk 91
RA 56

I'd like to calculate a boiled version of this water.

Thank you,
Ben

 

[Quaker]

Yes. It's in the Water book. The amount of bicarbonate that precipitates out is a function of the Calcium available. I studied up and tried doing such to salvage my really hard well water. It was visibly effective at removing a ton of minerals, but my water was simply too hard plus heavy in iron. I brewed a handful of batches which still had a mineral or blood twang to them. After some 1gallon side by side experiments, I ended up going with an RO filter after my water softener.

Ca ions final = Ca ions initial - ((HCO3 ions initial - 61)/3.05)

The 61 is a typical final amount of bicarbonate. You can't remove it all. "80 is more typical when calcium is not the limiting quantity."

I used 80 in my calcs, because I was adding sufficient calcium in the form of gypsum to end up with 50ppm Ca in the end.

Any moment now Brungard should be jumping in and correcting anything I got wrong.

 

[EJay]

You could always boil some and send it to the lab, then you'd know for sure.

 

[Bennypapa]

You could always boil some and send it to the lab, then you'd know for sure.

I don't have time to get that done before the brewing event that will have boiled and not boiled water available unfortunately.

 

[ajdelange]

Boiling and lime treatment both involve precipitation and precipitation can be tricky. As a general rule of thumb you can, if you have more than 1 mEq/L (50 ppm as CaCO3) of both calcium and alkalinity, you can reduce the one that was originally smaller to 1 mEq/L. Thus if you have water with calcium content of 60 mg/L (3 mEq/L = 150 ppm calcium hardness) and alkalinity of 200 ppm as CaCO3 (4 mEq/L) you can reduce the calcium to 1 mEq/L (drop it by 2) thereby simultaneously dropping alkalinity by the same amount to 2 mEq/L. If you want to get is lower the obvious trick is to add supplemental calcium before boiling. If you added 2 mEq/L Ca++ bringing the total to 5 you could then drop the alkalinity to 1 (i.e. by 3) at the same time removing 3 mEq/L Ca++ leaving 2.

Because of the trickiness of precipitation physics it really behooves you to check alkalinity and pH after you have attempted decarbonation by either boiling or lime.

 

[Bennypapa]

Yes. It's in the Water book.

Ca ions final = Ca ions initial - ((HCO3 ions initial - 61)/3.05)

I'm swimming out of my depth here so I'm not quite sure about the "ions" part.

If I have water with
Ca 41.4 ppm
hco3 110

can I plug those numbers into above formula?? for example

Ca ions final = Ca ions initial 41.4 - ((HCO3 ions initial 110 - 61)/3.05)
CaF=41.4-(49/3.05)
CaF=25.33

if so, how do you come up with the hco3 final of 61.


ugh, looks like I need to get the water book.
My bookshelf already sags.

 

[ajdelange]

You have 41.4/20 = 2.07 mVal of calcium. We need your alkalinity number but can WAG that from the bicarbonate as alk ~ 110/61 = 1.8 mVal. This is smaller than the calcium hardness so we assume it is limiting and could be reduced to 1.0 mVal i.e. by 0.8 thus dropping 0.8 mVal of calcium as well. 2.08 - 0.8 = 1.28 and this would be your post treatment calcium level corresponding to 1.28*20 = 25.6 mg/L calcium. You alkalinity would be presumed to be about 1*50 = 50 ppm as CaCO3. Your bicarbonate will depend on the pH but if that is nominal it will be about 61. These are approximate numbers and should be verified by test. I'll also note that with alkalinity and hardness numbers this low you might not see any precipitation.

 

[Bennypapa]

Here's the report.
Not quite a Wards report. PH from other reports in the area average 7.7.

Sodium, Na 22.3
Calcium, Ca 41.4
Magnesium, Mg 9.9
Total Hardness, CaCO3 144
Sulfate, SO4-S 55
Chloride, Cl 30

Bicarbonate, HCO3 110.2
Total Alkalinity, CaCO3 91

 

[mabrungard]

As AJ said, its not an easy assumption when precipitation dynamics are involved. Although a water can have the requisite 1 meq/L of calcium and alkalinity, there can be other factors that can prevent any precipitation by boiling or lime softening. The stoichiometric ratios of the predominant cations and anions in drinking water have to be favorable for the precipitation to occur. For instance, the sodium, sulfate, and chloride content in the water above will limit the degree to which it can be softened by boiling. In essence, water has to have high temporary hardness to enable the boiling technique to work.

 

[Bennypapa]

Thank you all!

This is exactly what I needed to know.

 

[Quaker]

I knew all I had to do was comment enough to bump this up to catch notice of the experts.

 

[Bennypapa]

i knew all i had to do was comment enough to bump this up to catch notice of the experts.

ha!
Lol