Very Soft Water Issues

[Rick_UK]

Hi Chaps

This may be very simple as chemistry was by far my worst subject! But my mash ph always seems to be too high, usually around 5.7, and this is with 2 teaspoons of gypsum in the mash (for a 25l batch). This seems vey odd to me as there should be very little alkalinity in the water due to it being so soft. The stats from my water report are:

Calcium - 16.1mg Ca/l
Magnesium - 1.29 mg Mg/l
Sodium - 6.52 mg Na/l
Carbonate - not given
Total Hardness - 18 mg Ca/l
Sulphate - 36.2 mg SO4/l
Chloride - 8.51 mg Cl/l

When I put the numbers into the calculator It tells me to use about 5g of gypsum and about half the amount of Calcium Chloride, but I have not used any of the latter as I though this would raise the ph further.

Adding like 3 - 4 teaspoons (15-20g) of gypsum seems like rather a lot, but is this what I need to do? And why does the calculator say to use much less and add the calcium chloride!! All I can think is the water report is wrong and my water is really not that soft - but there is no evidence of it being hard with limescale deposits in the kettle etc.

Any advice much appreciated from anyone good at chemistry.

Many thanks


Rick

[gregorach]

Calcium chloride will lower the pH, not raise it.

I also have very soft water, and for a typical bitter I end up using about 13g of gypsum, 4g calcium chloride, and 2g of epsom salts (to treat 30L of liquor, for both mash and sparge), which brings my mash pH nicely into the 5.2 - 5.3 range.

[Aleman]

I have the same water as you Rick, and for a 'standard' bitter I would add around 7.5g of calcium sulphate (gypsum) and 4g of calcium chloride, for a 30L liquor volume . . . normally hit a mash pH of around 5.3.

One thing to be aware of is our friends at United utilities often change where they draw the water from and I have seen the alkalinity jump from 25 up to 135ppm overnight which would have had a serious effect on mash pH if I hadn't checked it before brewing.

Although the salts of calcium raise the pH of the water you add it to, it will reduce the pH of the mash as the calcium reacts with phosphate released in the phytin reaction leaving free hydrogen ions floating about which drop the mash pH

[Rick_UK]

Thanks for the advice fellas. But I still don't understand why my adding more gypsum hasn't brought it down much if at all.

Aleman - I will emulate your treatment with my next brew and see how it goes - good to hear from someone sucessfully using the same water! But how do I check the alkalinity before I brew(I have ph papers but they range from 5 - 6ish)? I'm worried my water might not be what UU say it is now! Also if you know the alkalinity how does this affect the judgement of treatment salts?

Sorry for all the questions and thanks for helping.

Rick

[greenxpaddy]

I wonder if you have fallen in to the trap I noticed here in a previous post regarding the hardness input on the calculator from the UU report....

We have very soft water here. that said the additions for 45L are not significant and you probably could do without....though the whole point was to help Bobba with the test of his app to see if it correlates.

Just double checked its 10mg Calcium per litre, or 25mg Calcium Carbonate per litre for that hardness in Clarke degrees. Does that make the Co3 15mg then? - i.e. all the calcium in the water is from the carbonate? Sounds about right looking at the periodic table, the weight of the carbonate to the calcium is 1.5 times Ca weight.

Edit:

Some may wonder why the Hardness factor is 10mg Ca when the Rammie report is actually 8mg Ca. This is because the hardness is specified as

"The hardness is indicated by a calculation where both calcium and magnesium values are reported as mg/L (ppm) (Ca x 2.5) + (Mg x 4.12)= Hardness in mg/L"

So the hardness is equivalent to 10mg Ca but actually in the water there are Magnesium salts adding to the hardness. So therefore the weight of CO3 can be deduced as 1.5 x Ca value of 8mg from the report = 12mg/L presuming all Ca is in carbonate form.

BALLS

I have been using the wrong hardness figures on the calculator - putting in the Ca milligrams not the whole calcium carbonate weight. So I should be using 20mg calcium carbonate per litre or 12mg carbonate only per litre under hardness box input. How the heck have I done that.

Now to correct all my figures. And guess what the lager now requires no chalk and nominal gypsum. Spot on Aleman!

EDIT 2:

Ok now have all the figures again.

Bobba I have tried again with yours. But its still not reaching the same figures.

If you have underestimated the alkalinity you will end up with an overly acidic mash.....With your total Ca given at 16mg/L you can deduce that the carbonate will be 1.5 x that i.e. 24mg. So either enter 40mg CaCO3 on calculator or 24mg CO3.

You think you're soft but you are twice as hard as me! And i would have thought we would be getting roughly the same water! Clearly ours comes from one of these Calf Hey Reservoir, Ogden Reservoir and Holden Wood Reservoir (Grane Road)and yours doesn't.

i get these results from the calculator for a bitter with your report data

For 25L add

Salt 2.1g
Gypum 9.1g
CaCl 4g
Epsom 2.1g

[WallyBrew]

.....With your total Ca given at 16mg/L you can deduce that the carbonate will be 1.5 x that i.e. 24mg. So either enter 40mg CaCO3 on calculator or 24mg CO3.

Well you could do that .. but .. it's wrong.

From the figures given by Rick the total alkalinity as calcium carbonate calculates as 10.1mg/L

[greenxpaddy]

.....With your total Ca given at 16mg/L you can deduce that the carbonate will be 1.5 x that i.e. 24mg. So either enter 40mg CaCO3 on calculator or 24mg CO3.

Well you could do that .. but .. it's wrong.

From the figures given by Rick the total alkalinity as calcium carbonate calculates as 10.1mg/L

Wally I don't see anywhere he has quoted 10.1mg/L for CaCO3 - he doesn't know the CO3!

Just to add, I know the above is correct theory because I worked back into Degrees Clarke and back again and it all correlates fine with the published data from UU.

From wikipedia

*
o Clark degrees (°Clark)/English degrees (°e or e)
One degree Clark is defined as one grain (64.8 mg) of calcium carbonate per Imperial gallon (4.55 litres) of water, equivalent to 14.254 ppm.

IMPORTANT
Although most of the above measures define hardness in terms of concentrations of calcium in water, any combination of calcium and magnesium cations having the same total molarity as a pure calcium solution will yield the same degree of hardness. Consequently, hardness concentrations for naturally occurring waters (which will contain both Ca2+ and Mg2+ ions), are usually expressed as an equivalent concentration of pure calcium in solution. For example, water that contains 1.5 mmol/L of elemental calcium (Ca2+) and 1.0 mmol/L of magnesium (Mg2+) is equivalent in hardness to a 2.5 mmol/L solution of calcium alone (250.2 ppm).

PPS work out the atomic mass of one Ca atom and you will see the combined atomic mass of CO3 is near enough 1.5 times the mass!

[WallyBrew]

He doesn't and he didn't.

You appear to be accepting that all the calcium is combined with carbonate and also, it appears, accepting that hardness and alkalinity are interchangeable which they are not.

In order to calculate the alkalinity it is necessary to know the following:- Na, K, Ca, Mg, Cl, SO4, NO3. Then the (sum of the milliequivalents of the cations - the sum of the milliequivalents of the anions) x 50 = the alkalinity in mg of calcium carbonate per litre. In most waters the sodium and potassium combine with all the chloride and none of the sulphate. Therefore some of the calcium is combined with the sulphate. This calcium contributes to the hardness but not to the alkalinity.

From Ricks figures the sodium combines with all the chloride and leaves some sodium (6.52-(8.51/35.5*23)) = 1.01mg of Na left which will combine with 2.1 mg of sulphate. This will leave 34.1 mg of sulphate and this will combine with 14.2 mg of Ca. So we now have 1.9 mg of Ca which = 4.75 as CaCO3 and 1.29 of Mg which = 5.38 as CaCO3

[Rick_UK]

Holy shit! Now I am lost??!!

[greenxpaddy]

From Ricks figures the sodium combines with all the chloride and leaves some sodium (6.52-(8.51/35.5*23)) = 1.01mg of Na left which will combine with 2.1 mg of sulphate. This will leave 34.1 mg of sulphate and this will combine with 14.2 mg of Ca. So we now have 1.9 mg of Ca which = 4.75 as CaCO3 and 1.29 of Mg which = 5.38 as CaCO3

Hi I'm trying to follow you here. Did you def mean the last word. or did you mean as MgCO3

I am trying to work through this very carefully as it is really important in my eyes.

I agree with your science. It is correct. From the point of view of using the calculator only the Cations Mg and Ca matter. That is what you are trying to balance for the mash. The calculator allows you as a last resort to use Hardness. This is declared for Rich's sample from UU in Degrees Clarke (3.15) which converted is equivalent to 50.4 mg CaCO3 /L . Not actually.... as the hardness is made up of Ca and Mg cations as salts sulphates and carbonates. If you enter this figure into the calculator then balance the CO3 the additions are identical with the scenario of ignoring the top boxes and doing your calcs and simply entering the 6 boxes next to 'Enter Your Water Composition' - all except for the small addition of chalk it recommends when you enter the exact CO3 level in your way.

In fact the additions turn out the same by my originally stated method and yours barring the chalk.

I am really grateful for you explaining how to work out the carbonate as this will help with chalk addition calculations.

Maybe the missing chalk is what is affecting ph but it doesn't really seem enough (1g in 25L) to alter the ph that much

BTW I have just tried to calculate my carbonate using your method and it doesn't work

my figures are

Ca 8
Mg 1.4
Na 7.7
SO4 22
Cl 8

[WallyBrew]

Hi I'm trying to follow you here. Did you def mean the last word. or did you mean as MgCO3

The magnesium is indeed expressed as CaCO3.

BTW I have just tried to calculate my carbonate using your method and it doesn't work

my figures are

Ca 8
Mg 1.4
Na 7.7
SO4 22
Cl 8

I do not know what you made it but I make it 8.3mg/L as CaCO3. This is low and as previously pointed out you do need to know the K and NO3 as well.

Bear in mind that the figures from your utility company are averages. If they took 10 samples for chloride and 18 samples for sodium then the averages will not necessarily relate and this is especially so if the samples for each analyte were taken on different sampling dates.

The best way of finding out your alkalinity is by referring to the appropriate sections in the BREWNIVERSITY and ignoring total hardness, and most other information provided by your utility company.

If one has access to an analysis of a single sample such as the one below (my water from the 28th June 2010)

all results in mg/L

sodium 12
potassium 1.7
calcium 105
magnesium 2.4
chloride 22
nitrate 26
sulphate 17
total alkalinity as CaCO3 231

then the hypothetical composition and hence alkalinity can be worked out (this HAS NOT been taken from wikipedia so is equally as fallible)

To work out the hypothetical composition one combines the cations in the order K, Na, Ca, Mg with the anions in the order Cl, NO3, SO4

So for the above

divide K by 39.098 and multiply by 35.453 to get the amount of Cl that combines with K and add this figure to K to get KCl
In numbers 1.7 / 39.098 x 35.453 = 1.54
1.54 + 1.7 = 3.24 so we have 3.24mg/L of KCl

Subtract 1.54 from the chloride (22) to give 20.46 uncombined chloride

Move to the next cation which is sodium
divide Na by 22.99 and multiply by 35.453 to get the amount of chloride that combines with Na to give NaCl
In numbers 12 / 22.99 x 35.453 = 18.51
12 + 18.51 = 30.51 so we have 30.51mg/L of NaCl

subtract 18.51 from 20.46 to give 1.95mg/L of uncombined chloride

Move to next cation which is calcium
by inspection there is insufficient chloride to combine with all the chloride so work out how much calcium combines with the remaining chloride
divide remaining chloride by 35.453 and multiply by 20.04 to get the amount of calcium that combines with the chloride
In numbers 1.95 / 35.453 *20.04 = 1.10
1.95 + 1.10 = 3.05 so we have 3.05mg/L of CaCl2

subtract 1.10 from 105 to give 103.9mg/L of uncombined calcium

Move to next anion which is nitrate
divide NO3 by 62.004 and multiply by 20.02 to get the amount of calcium that combines with the nitrate
In numbers 26 / 62.004 x 20.04 = 8.40
26 + 8.4 = 34.4 so we have 34.4mg/L of Ca(NO3)2

subtract 8.40 from 103.9 to give 95.5mg/L of uncombined calcium

Move on to next anion which is sulphate
divide SO4 by 48.03 and multiply by 20.04 to get the amount of calcium that combines with the sulphate
In numbers 17 / 48.03 x 20.04 = 7.09
17 + 7.09 = 24.09 so we have 24.09mg/L of CaSO4

Subtract 7.09 from 95.5 to give 88.41 of uncombined calcium

There are now no more anions so:-

multiply 88.41 by 50.04 and divide by 20.04 to express the uncombined calcium as calcium carbonate
so we have 220.72mg/L of calcium carbonate

multiply the magnesium by 42.15 and divide by 12.15 to express the uncombined magnesium as magnesium carbonate
so we have 8.33 mg/L of MgCO3

We can also express the Mg as CaCO3 by dividing 2.4 / 12.15 and multiplying by 50.04 = 9.88mg/L

So the total alkalinity as CaCO3 = 9.88 + 220.72 = 230.6



As you seem to want to use chalk for increasing your alkalinity here are my own thoughts on this subject
(the mathematics have never been checked so could be completely wrong!)

Thoughts on adding calcium carbonate.

Due to its virtual insolubility in water calcium carbonate is usually added to the grist. Such an addition is not going to be very homogenous.

So will it work?

First lets assume that we are going to add 1g of calcium carbonate to 4kg of grist and mash with 10 litres of water. What we are attempting to do is raise the alkalinity of the water to 100mg/L as calcium carbonate.

Now for some numbers. The molecular mass of calcium carbonate is 100. This means that one mole of calcium carbonate weighs 100g. The mole is defined by Avogadros constant which is 6.02 x 10^23. This number is the number of molecules of calcium carbonate in 100g so our 1g contains 6.02 x 10^21 molecules. For the rest of this we'll assume that all calcium carbonate molecules are spherical and all calcium carbonate particles are spherical. Next we need to know how many calcium carbonate particles are in 1g and at this point we'll guess at 1,000,000 or in other words each particle weighs in at 1 microgram. This means 1 milligram contains 1,000 particles and this is probably far more than are really present.

So our 1g of calcium carbonate comprises 10^6 particles and therefore one particle contains (6.02 x 10^21) / (10^6) = 6.02 x 10^15 molecules. Which is still a huge number. Based on it being a sphere only the molecules at the surface are available to react and the number at the surface is 1.60 x 10^11which whilst this sounds like a large number is only 1/37,000 of the total available. These will have to react and move away before the molecules underneath can react. As the reaction product is calcium phosphate which is insoluble it is quite likely that eventually the surface will become covered with this such that the remaining calcium carbonate may never become available. Bear in mind that although 1,000,000 particles sounds like a big number, in the context of the amount of phosphate available (which will be homogenous) it is small and so without constant agitation the chances of all the calcium carbonate ever being used up seems slim.

[simple one]

Will the CaCO3 particles react with the H+ ions within the mash and boil, and hence increase the pH?

[greenxpaddy]

Very interesting.

I have done the calcs with my data, although I didn't have the K reading though based on the general salt levels in the soft water a rough broadline figure could be summised. Also using the min and max readings for some cations and anions on the UU report can also try to check how things might be different for each sample...

Basically I fall down quite early in the calcs because I have insufficent Cl for the Sodium, except if we use min Na and max CL readings. Regardless when we get to Ca there is too much SO4 for it so it would lead one to think that there is no CaCO3 and all the hardness comes from the MgCO3. Leading to a CO3 figure equiv to 4.85mg CaCO3..... V v soft. So I think I will stick to adding half a teaspoon of carbonate to each mash (48l liqour) and an extra 1/2tsp in mild and stout recipes (compared to previous calcs).

[InsideEdge]

You guys are too good at this sh*t!

I have very soft water and just add 1 tsp each of gypsum and calcium chloride to the mash and then then boil.

[simple one]

Although the salts of calcium raise the pH of the water you add it to, it will reduce the pH of the mash as the calcium reacts with phosphate released in the phytin reaction leaving free hydrogen ions floating about which drop the mash pH

So do gypsum and calcium chloride increase pH when added to the boil?