'Nother Water Question

One of the local breweries (Bear Republic) boils(?) their water the day or so before brewing with it to precipitate out some of the permanent hardness. So, this leads me to this question.

Is it necessary to boil the water or just get it hot. The reason I ask is.. my hot water heater has a case of the 'bumps' due to the hard water scale that has precipitated on the bottom.

I was wondering if I could simply use hot water from my water heater rather than boiling the water.. hot or cold.. and letting it sit and siphon. That would save a lot of time.. and energy.

Thanks, Bill

It will make a slight difference, but it will not drop the calcium or bicarbonate content like a vigorous boil will. Sorry.

No, it is not necessary to boil the water but it is necessary to sparge out the CO2 that forms as a result of the precipitation reaction:
Ca++ + 2HCO3- <---> CaCO3 + CO2 + H2O

Heat is a factor because it makes both CO2 and CaCO3 less soluble. The CaCO3 falls out but it is also necessary to remove the CO2. When water boils steam sparges out the CO2 but you can also sparge with air, nitrogen... or you can spray the hot water through a shower head or nozzle.

The arrow in the chemical reaction above is double headed to remind us that CO2 dissolved in water is what dissolves limestone and is responsible for the presence of bicarbonate in water. When we decarbonate by heating we are simply reversing that reaction. LeChatelier's principle tells us that for the reaction to proceed to the right we need to get the products (CO2 and CaCO3) out of the solution. What has happened in your water heater is evidence that some bicarbonate can be removed without sparging. To get most of it (you can't get it all) by heating you must sparge.

Thanks guys.. not quite sure I understand the sparge Are you saying that after I boil the water I should aerate it? Can I do this by simply taking the boiled water and pouring it back and forth between buckets 10 or 20 times? Do I then let it sit and should see some precipitated material toward the bottom of the pot?

I don't know how good/bad my water is

I don't know what it's best for, as is.. and what it's worst for without diluting and making additions.

I have: Ca-20; Mg-18; K-0; Carbonate-5; Bicarb-158; Chloride-8; Sodium-8; Sulphate-18; Nitrate-2.5; Tot Dissolved Solids-160; Total Hardness 130; Total Alkalinity 130; pH-7.04

HopSong said:

Thanks guys.. not quite sure I understand the sparge Are you saying that after I boil the water I should aerate it?

Click to expand...

Yes

HopSong said:

Can I do this by simply taking the boiled water and pouring it back and forth between buckets 10 or 20 times?

Click to expand...

Yes, or by spraying it through a nozzle of some sort.

HopSong said:

Do I then let it sit and should see some precipitated material toward the bottom of the pot?

Click to expand...

Yes.

HopSong said:

I don't know how good/bad my water is

I have: Ca-20; Mg-18; K-0; Carbonate-5; Bicarb-158; Chloride-8; Sodium-8; Sulphate-18; Nitrate-2.5; Tot Dissolved Solids-160; Total Hardness 130; Total Alkalinity 130; pH-7.04

Click to expand...

Not too bad but you won't be able to decarbonate it by boiling unless you add calcium salts (chloride, sulfate) first. This you would want to do anyway because you will drop calcium as well as bicarbonate when you boil. The alkalinity is sufficient that you will need to do something about it: dilute it away with RO; precipitate it with boiling or lime treatment or neutralize it with acid.

Thanks again AJ..
So, does the spraying have to be done while the water is hot? Or will cold work? Maybe dumb question.. but, gotta ask to learn.

[q] Not too bad but you won't be able to decarbonate it by boiling unless you add calcium salts (chloride, sulfate) first. This you would want to do anyway because you will drop calcium as well as bicarbonate when you boil. The alkalinity is sufficient that you will need to do something about it: dilute it away with RO; precipitate it with boiling or lime treatment or neutralize it with acid.[/q]

This is in addition to additions that will be made during mashing? If so, for a non-chemist, is there a way to calculate how much acid and calcium salts would be needed per gallon or liter?

HopSong said:

Thanks again AJ..
So, does the spraying have to be done while the water is hot?

Click to expand...

Yes

You have to look at your calcium: 20 mg/L ~ 1 mVal (i.e. divide the calcium mg/L by 20) and your alkalinity: 130 ppm as CaCO3 = 130/50 = 2.6 mVal. You can, as a rule of thumb, decarbonate/soften down until the lesser of these numbers is 1 mVal which level you are already at and that's why I say extra caclium is added. Let's say you want to get out all the alkalinity you can and want to have 50 mg/L Ca++ left over when you finish. That would mean dropping 1.6 mVal of bicarbonate. To do that you would also need 2.6 mVal of calcium and you have 1 so you would have to add 1.6. You would then have 2.6 Ca++ and 2.6 alkalinity and you would expect to drop 1.6 of each leaving 1 of each. But you want 50/20 = 2.5 mVal calcium when all is said and done so you must add 1.5 more after you have finished. Best practice is t add 1.6 + 1.5 = 3.1 mVal Calcium before the boil (that's 3.1*20= 62 mg/L for either gypsum, calcium chloride or both). This may allow you to drop the alkalinity a bit below 1 mVal (50 ppm as CaCO3).

This is in addition to additions that will be made during mashing? If so, for a non-chemist, is there a way to calculate how much acid and calcium salts would be needed per gallon or liter?[/QUOTE]

You have to look at your calcium: 20 mg/L ~ 1 mVal (i.e. divide the calcium mg/L by 20) and your alkalinity: 130 ppm as CaCO3 = 130/50 = 2.6 mVal. You can, as a rule of thumb, decarbonate/soften down until the lesser of these numbers is 1 mVal which level you are already at and that's why I say extra caclium is added. Let's say you want to get out all the alkalinity you can and want to have 50 mg/L Ca++ left over when you finish. That would mean dropping 1.6 mVal of bicarbonate. To do that you would also need 2.6 mVal of calcium and you have 1 so you would have to add 1.6. You would then have 2.6 Ca++ and 2.6 alkalinity and you would expect to drop 1.6 of each leaving 1 of each. But you want 50/20 = 2.5 mVal calcium when all is said and done so you must add 1.5 more after you have finished. Best practice is t add 1.6 + 1.5 = 3.1 mVal Calcium before the boil (that's 3.1*20= 62 mg/L for either gypsum, calcium chloride or both). This may allow you to drop the alkalinity a bit below 1 mVal (50 ppm as CaCO3).

Thanks for taking the time to handhold this old guy

No problem. I'm not exactly a spring chicken myself.

Maybe.. but you know and understand chemistry.. This guy struggled thru basic organic and inorganic 50+ yrs ago and never looked back.. I guess I should have re-taken chem at a later date when I found a real need for it rather than filling my curriculum needs.

Much the same here (tho I never did organic). Eventually I did find a need for it and that was, of course, brewing!