Alkalinity, Testing Your Tap Water

(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!
Post Reply
WallyBrew
Hollow Legs
Posts: 473
Joined: Sat Jan 05, 2008 11:30 pm
Location: Surrey

Re: Alkalinity, Testing Your Tap Water

Post by WallyBrew » Wed Mar 04, 2009 7:29 pm

You're fudging it.

The hardness figure you have is the sum of the calcium expressed as calcium carbonate and the magnesium expressed as calcium carbonate - so the figure you get for calcium when you enter your hardness includes the magnesium. If you add 2.5 magnesium then you are adding something that isn't there and you'll have to adjust your calcium by subtracting 2.5/24*40 or about 4mg/l from it.

Clear as mud?

SiHoltye

Re: Alkalinity, Testing Your Tap Water

Post by SiHoltye » Wed Mar 04, 2009 7:41 pm

I love looking at your calculator Graham, I question how I use it everytime :lol:

From your passage below, do people think I'm reading this right?

Adding Your Water Treatment Stuff
If using CRS, this is always added to the total liquor before brewing. With the exception of calcium carbonate, which is always added to the mash in proportion to the amount of mash liquor, the best place to add the salts is generally to the total volume of the liquor. However, calcium sulphate can be difficult to get into solution in cold water, as is usually the case when using CRS. The other salts go into solution easily. There are two ways of overcoming the difficulty of getting calcium sulphate into solution. One is to premix it in a small volume of liquor using a food processor or a hand blender before adding it to the main liquor. The other is to split the calcium sulphate into two portions, one in proportion to the volume of mash liquor and the other for the remainder of the total liquor. The proportion for the mash is mixed in with the grist prior to mashing, and the remainder is added to the wort boil. This has the disadvantage that sparge water is untreated which, ideally, should be treated, although it probably doesn't matter too much if it is not. For this reason, premixing and adding the sulphate to the total liquor is preferred. Even if boiling the liquor to remove carbonate, it is a good idea to premix the sulphate before adding it to the liquor boil.

The calcium-bearing salts are required for mash reactions, so it is important that these are present in the mash in the correct proportions. The other common salts, magnesium sulphate and sodium chloride, are not particularly important for the mash, and they can be just as effectively added to the wort boil. In fact, for slightly technical reasons, it is probably better if the magnesium and sodium salts are added to the wort boil. Calcium carbonate should only be added to the mash. It should not be added to any other liquor including the sparge liquor. The carbonate is detrimental to brewing processes beyond the mash.


CRS = based on total liquor, add in the HLT
CaSO4 = based on total liquor in the HLT, or split proportionally between mash and copper (though in the HLT preferred)
CaCl = based on mash liquor volume only (not total liquor) and mixed with dry grist before doughing in. This is where I'm not sure
MgSO4, NaCl, others = added to the boiling copper

'Til now I've based the CaCl on total liquor, and along with the rest of the salts split them into the mash and copper proportionally (didn't read your small print :oops: )
Thanks for any help.

adm

Re: Alkalinity, Testing Your Tap Water

Post by adm » Wed Mar 04, 2009 8:13 pm

WallyBrew wrote:You're fudging it.

The hardness figure you have is the sum of the calcium expressed as calcium carbonate and the magnesium expressed as calcium carbonate - so the figure you get for calcium when you enter your hardness includes the magnesium. If you add 2.5 magnesium then you are adding something that isn't there and you'll have to adjust your calcium by subtracting 2.5/24*40 or about 4mg/l from it.

Clear as mud?

Hmm.....clear as thick mud anyway.

When I enter my Total Alkalinity figure, the calculator spits out a Carbonate figure. I'm OK with that...

Then I see that when the Hardness figure is entered into the box it spits out Calcium and Sulphate figures into the rest of the calculator, and that as it's a Total figure, that would also include any Magnesium component too. So far so good. The Ion Balance is good. Happy....

Now - where I get confused is that if I then plug in the Sodium, Sulphate and Chloride figures from the Waterco, without adding anything into the Mg field, my Ion Balance Check doesn't balance anymore. (3.27:3.7)

The Sulphate figure from the Waterco is approx twice as high as that given by the cal to this stage (9.6 vs 20.2)
The Chloride figure is 20.5 and the Sodium is 8.6

So......should I just ignore that the water doesn't balance because I don't know how the Hardness splits out between Calcium and Magnesium?

Or am I just thinking about this too much?

Are there any equivalent test kits to the Salifert ones that I could use to get accurate figures for the other parameters ?

I know - I'm too anal...

Chappie519

Re: Alkalinity, Testing Your Tap Water

Post by Chappie519 » Wed Mar 04, 2009 8:32 pm

Graham wrote:
Chappie519 wrote:So using grahams liquor treatment calc here I would put 36 into the hardness box or the alkalinity box at the top? and that would be in CaCO3?
Yes put it in the alkalinity box. Sometime in the future I'll probably remove the hardness box or move it out of temptation's way to save confusion.

However, you have just about the ideal amount of alkalinity for pale ales, so it is mostly academic. You will not have to use any reduction stuff like CRS. You'll need to add some calcium though, and possibly a bit of magnesium for luck.
Cheers Graham! Ill try some gypsum and epsom next time I brew pale!

Chappie

WallyBrew
Hollow Legs
Posts: 473
Joined: Sat Jan 05, 2008 11:30 pm
Location: Surrey

Re: Alkalinity, Testing Your Tap Water

Post by WallyBrew » Wed Mar 04, 2009 8:35 pm

ADM - You are thinking about it too much.

The sulphate arriving after entering the hardness is reasonable because most waters contain sulphate and the excess calcium/magnesium has to balance with something. Your sulphate could well be greater and, indeed, could be less than this figure but assumptions have to be made when there is a shortage of information.

You also do not have a potassium figure or a nitrate figure so the fact that it doesn't properly balance at the end of the day is of no real concern.

The only test kit that might be worth buying is a calcium one but if you do buy one make sure it is a calcium test kit and not a TOTAL HARDNESS one.

adm

Re: Alkalinity, Testing Your Tap Water

Post by adm » Wed Mar 04, 2009 8:46 pm

WallyBrew wrote:ADM - You are thinking about it too much.
:roll: It's one of my many personality flaws!

I'll just chill about it all......in any event, the quality of my beer since I started treating the water has definitely gone up, so I'm happy.

I just like to know how things work...GODDAM THAT WATER COMPANY FOR NOT PROVIDING ALL THE FIGURES!!! :twisted:

Graham

Re: Alkalinity, Testing Your Tap Water

Post by Graham » Wed Mar 04, 2009 9:22 pm

ADM
The problem with using the hardness box is that the alkalinity you measured is more accurate than the hardness figure given by the water co. Indeed, sometimes the hardness figures given are derived by approximating it from other measured parameters because domestic users don't really need it to much accuracy; it is typically used to judge how much soap powder to use in washing-machines, and a few tens of milligrammes per litre here or there is not going to make much difference to that. With brewing, particularly when using CRS, it is a different matter.

When there is a figure in both the alkalinity and the hardness boxes, and if the figures do not match up (they never do), it then has to do some guesswork to compensate for the discrepancy. It always determines the carbonate from alkalinity, and derives the calcium from the hardness figure. If the milliequiv figures do not tally, then it does some guessing. If the error is in one direction it assumes that some magnesium is bound to it, in the other direction it assumes sulphate, and adds it accordingly. When I wrote it I assumed that the hardness figures given out were more accurate than they really are. The hardness box was possibly a bad idea.

So it is probably better to guestimate calcium from alkalinity. In your case 135 ppm of alkalinity gives 80.94 ppm of carbonate. To find the amount of calcium that will bind to it, divide your alkalinity figure by 2.497 = 54ppm of calcium. If you have your alkalinity in milliequivalents, then multiply the meq by 20.039.

If you have a figure for sulphate, then divide the sulphate by 2.397 to find the calcium bound to that. Add the two calcium figures together.

There will possibly be some magnesium in there somewhere, but as we have no way of knowing how much, we ignore it. It will not make much difference anyway.

One day I'll do a better water-guesser for the calculator.

Graham

Re: Alkalinity, Testing Your Tap Water

Post by Graham » Wed Mar 04, 2009 9:49 pm

SiHoltye
With calcium chloride, adding it to the total water is preferred (after CRS treatment), cos then your sparge water is treated as well. It goes into solution just by looking at it, so there is no problem there.

Calcium sulphate would also be better added to the total water, but it is a bugger to get into solution without boiling it in. CRS users do not normally boil their water, so it is a bit of a challenge. Whizzing it into solution in a food blender or with an electric whizzy stick in some warm or hot water, is one answer. Boiling it into solution in a saucepan is another. Splitting it in proportion and adding it to the mash and the wort boil is another. It will react okay and do its job in the mash, and the stuff added to the copper will get boiled into solution. The problem with the last option is that the sparge liquor isn't treated.

Calcium carbonate is always added to the mash (when necessary), because you don't want the stuff anywhere else.

adm

Re: Alkalinity, Testing Your Tap Water

Post by adm » Wed Mar 04, 2009 10:38 pm

Graham wrote:ADM
The problem with using the hardness box is that the alkalinity you measured is more accurate than the hardness figure given by the water co. Indeed, sometimes the hardness figures given are derived by approximating it from other measured parameters because domestic users don't really need it to much accuracy; it is typically used to judge how much soap powder to use in washing-machines, and a few tens of milligrammes per litre here or there is not going to make much difference to that. With brewing, particularly when using CRS, it is a different matter.

When there is a figure in both the alkalinity and the hardness boxes, and if the figures do not match up (they never do), it then has to do some guesswork to compensate for the discrepancy. It always determines the carbonate from alkalinity, and derives the calcium from the hardness figure. If the milliequiv figures do not tally, then it does some guessing. If the error is in one direction it assumes that some magnesium is bound to it, in the other direction it assumes sulphate, and adds it accordingly. When I wrote it I assumed that the hardness figures given out were more accurate than they really are. The hardness box was possibly a bad idea.

So it is probably better to guestimate calcium from alkalinity. In your case 135 ppm of alkalinity gives 80.94 ppm of carbonate. To find the amount of calcium that will bind to it, divide your alkalinity figure by 2.497 = 54ppm of calcium. If you have your alkalinity in milliequivalents, then multiply the meq by 20.039.

If you have a figure for sulphate, then divide the sulphate by 2.397 to find the calcium bound to that. Add the two calcium figures together.

There will possibly be some magnesium in there somewhere, but as we have no way of knowing how much, we ignore it. It will not make much difference anyway.

One day I'll do a better water-guesser for the calculator.
Thanks Graham,

First - I really appreciate your help with all this. I know it must be a pain sticking the calc up there and then answering all the questions that come from it.

Second - even misusing it, my beers have really come on.....so it's a great resource. Thanks again.

Having said that, I have a few more questions.... :twisted: :twisted:

You said that "in your case" 135ppm of Total Alkalinity gives 80.94 ppm of carbonate. Why is this? I'd like to understand the chemistry, but being an electronic engineer at heart, I have problems here... However, presuming that there's a 1.66 constant in action somewhere here, I can deal with it. Moving on to the Calcium.....why do I divide the alkalinity by 2.497 ? Again - being a chem nonuff, this is probably a daft question to do with moles and binding amounts. Anyway...135/2.497 = 54

I do have a Sulphate figure....20.2mg/L...which when divided by 2.397 (why 2.397 this time rather than 2.497 as before? Typo or chem stuff again?) = 8.427.

OK - so now I have two Calcium figures - 54+8.43 = 62.43

So that's the Calcium sorted - plug 62.43 into the box.

Now if I enter the figures I have for Sodium, Sulphate and Chloride into the remaining boxes (leaving Mg blank), I'm getting closer...

Ion Balance is now 3.49:3.7 - I'm presuming this is good enough for Government work now as I don't know the Mg content....

Anyway.....given the above, I'm now looking at 30ml of CRS for 50L (same as always), plus about 6g Gypsum (a teaspoon) 5g of Epsom Salts (another teaspoon), plus a g each or so of Calcium Chloride and good old table salt to match the General Purpose setting on the calculator.

Does that sound about right....and any background you can share on the constants would be appreciated.

Cheers,

Alasdair

SiHoltye

Re: Alkalinity, Testing Your Tap Water

Post by SiHoltye » Wed Mar 04, 2009 11:33 pm

Graham wrote:SiHoltye
With calcium chloride, adding it to the total water is preferred (after CRS treatment), cos then your sparge water is treated as well. It goes into solution just by looking at it, so there is no problem there.

Calcium sulphate would also be better added to the total water, but it is a bugger to get into solution without boiling it in. CRS users do not normally boil their water, so it is a bit of a challenge. Whizzing it into solution in a food blender or with an electric whizzy stick in some warm or hot water, is one answer. Boiling it into solution in a saucepan is another. Splitting it in proportion and adding it to the mash and the wort boil is another. It will react okay and do its job in the mash, and the stuff added to the copper will get boiled into solution. The problem with the last option is that the sparge liquor isn't treated.

Calcium carbonate is always added to the mash (when necessary), because you don't want the stuff anywhere else.
I feel foolish for not spotting CaCl/CaCO3 confusion I'd caused myself #-o but rather than batting me away you've helped and got me wondering if I can dissolve all salt additions (aside from CaCO3 - not that I need any anyway) in a pan of say 500ml of campden treated liquor drawn from the HLT. The CaS04 being aggressively stired and dissolved first maybe with boiling necessary, as that cools down, dissolve the remaining salts into the 500ml as well. Treat the HLT with CRS if/as required, then return the salts mixture to the HLT, heat up and off I go.

The unknown for me would be if any untoward reaction that might occur because of the heat or concentrated nature of the 500ml 'salted' water solution. Can anyone think of a problem with this?

Graham

Re: Alkalinity, Testing Your Tap Water

Post by Graham » Thu Mar 05, 2009 1:21 am

ADM
I'm an electronics engineer too. There are quite a few of us on here. Now to the difficult stuff. This is where I show you how to make 2+2 = 2!

You will observe that the water treatment calculator is split into two groups: Cations and Anions. The cations are: calcium, magnesium, and sodium. The anions are carbonate, sulphate, and chloride.

Any one of the cations can combine with any one of the anions to produce a compound salt - giving nine possible combinations. For example calcium can combine with (or bind with) carbonate to produce calcium carbonate, or with sulphate to produce calcium sulphate. Neither the cations or the anions can exist in isolation, they must be bound to something. To determine how much of this will bind with how much of that, we use a set of magic numbers known as equivalent weights. These are derived from atomic weights and valence electrons.

By dividing the weight of the ion, or salt, by the equivalent weight, we end up with a number which, because we are dealing in ppm or mg/l, are called milliequivalents.

basically, 1 milliequivalent of a cation will bind with one milliequivalent of any anion to produce 1 milliequivalent of the compound thingy. Thus 2 milliequivalents of calcium will combine with 2 milliequivalents of carbonate to produce 2 milliequivalents of calcium carbonate. Some equivalent weights are given below.

The ions
Calcium Ca = 20.039
Magnesium Mg = 12.1525
Sodium Na = 22.989769
Carbonate CO3 = 30.00445
Sulphate SO4 = 48.0313
Chloride Cl = 35.453

Bicarbonate HCO3 = 61.0168;

The compounds
Calcium Carbonate CaCO3 = 50.04345
Calcium Sulphate CaSO4 = 68.07
Calcium Chloride CaCl2 = 55.49
Magnesium Sulphate MgSO4 = 60.19
Sodium Chloride NaCl = 58.44

In your case to convert 135 mg/l of alkalinity expressed as calcium carbonate to milliequivs =

135/50.04345 = 2.697 milliequivalents. Where 50.04345 is the eqiv weight for calcium carbonate from the table above.

To express it as carbonate, multiply 2.697 by the eqiv weight for carbonate. 2.697 * 30.00445 = 80.94 mg/l of carbonate;

2.697 meq of carbonate can be bound to 2.697 * 20.039 = 54.045 mg/l of calcium. Giving your first calcium figure.

Your sulphate figure of 20.2 mg/l can bind with 20.2 / 48.0313 = 0.421 meqs of calcium, which equals 0.421 * 20.039 = 8.436 mg/l of calcium, giving your second calcium figure. So yes, your total calcium is 62.4 as you state.

Of course the carbonate could be bound to other stuff, but we are forced to ignore magnesium without a definitive figure for it, and any sodium usually pairs up nicely with the chloride to within a knat's cock so that can usually be ignored too.

The other numbers I gave for directly converting are simply the ratios of the equivelent weights: sulphate / calcium = 48.0313 / 20.039 = 2.397 giving one magic number. The other is calcium carbonate / calcium = 50.0435 / 20.039 = 2.497, giving the other.

That's really muddied the liquor.

Graham

Re: Alkalinity, Testing Your Tap Water

Post by Graham » Thu Mar 05, 2009 2:09 am

SiHoltye wrote: ...if I can dissolve all salt additions (aside from CaCO3 - not that I need any anyway) in a pan of say 500ml of campden treated liquor drawn from the HLT. The CaS04 being aggressively stired and dissolved first maybe with boiling necessary, as that cools down, dissolve the remaining salts into the 500ml as well. Treat the HLT with CRS if/as required, then return the salts mixture to the HLT, heat up and off I go.

The unknown for me would be if any untoward reaction that might occur because of the heat or concentrated nature of the 500ml 'salted' water solution. Can anyone think of a problem with this?
I see no problem with that. I've got considerable quantities of calcium sulphate to go into solution in 500ml of water in a food processor by way of experiment. However, with my old variable-speed food processor I can leave it running and go away and do something else, so it was not a very scientific experiment because I forgot about it and left it running for ages before I remembered about it. I boil all my brewing water before brewing, so I am able to boil it in normally.

It is only the calcium sulphate you need to worry about. The other stuff should go into solution no problem.

SiHoltye

Re: Alkalinity, Testing Your Tap Water

Post by SiHoltye » Thu Mar 05, 2009 2:19 am

My hero, thanks Graham. Have you thought about quitting this forum but leaving an 0905xxxxxx number, you might make a decent wedge if only you could put up with answering the same questions over and over again :lol: Prolly put unrepresentative Camra royalties in the shade :flip:

adm

Re: Alkalinity, Testing Your Tap Water

Post by adm » Thu Mar 05, 2009 9:01 am

Graham wrote:ADM

That's really muddied the liquor.
Graham, that's an absolutely perfect explanation.

Now I understand the mechanism behind it, it all makes sense. Now I need to go and do the sums once or twice to make sure I've got it....but hopefully that will be my last question on this part of the subject at least.

Many thanks! I had a lightbulb moment this morning when I read your post.

BTW - I haven't done any real engineering for twenty years or so.....fiddling with my brewery is the closest I get these days....

Bopper

Re: Alkalinity, Testing Your Tap Water

Post by Bopper » Mon Apr 27, 2009 2:35 pm

It might be of use for someone! Ive test the alkalinity about 20 times today its keep comming up with a figure of 227 Caco3, this is for Swindon-central........


Richard :D

Post Reply