P.h before mashing in

[MattGuk]

Hi all, just a quick question as water chemistry ain't really my thing.
Just getting set for making a cream ale tomorrow and with my water I need to add CRS as I have 137ppm alkalinity.
The p.h was 6.8 before adding CRS, calculations say I need about 30Ml and after adding my P.H of just my water is at 2.7.
Does this matter at all?

Cheers

[Eric]

pH of untreated liquor is of no importance to a brewer, alkalinity is what matters.
30 ml of CRS should be enough to treat 47 litres of water with alkalinity of 137ppm as CaCO3 for a pale beer and pH of the treated liquor would ordinarily be >4.4, not pH 2.7. Have you stirred the water to remove any CO2 and ensure the reaction is complete?

[MattGuk]

Thanks for the reply, I have stirred the water and I added the CRS a good few hours ago and it's now reading 2.7.
I used brewers friend to calculate how much to use, I guess either I have done something wrong or the calculator is off?

[WallyBrew]

Thanks for the reply, I have stirred the water and I added the CRS a good few hours ago and it's now reading 2.7.
I used brewers friend to calculate how much to use, I guess either I have done something wrong or the calculator is off?

What did you use when you did this on a previous occasion?

Over the past 6 weeks I have brewed 2 batches, both time checking my alkalinity with the Salifert KH kit.
First time my water had a reading of 156ppm so adjusted with CRS which I believe was about 21ml total in my mash ( no sparge ). The 2nd brew, the Alkalinity had dropped BIG TIME, to the point I am questioning my math, as the test indicate I had an alkalinity of 70ppm.

In the above with the 156 alkalinity you used 21mL but did you check the alkalinity after addition (not the pH)
As you brew in a Brewmonk presumably the quantity of water treated was 30L?
If so then (alkalinity - required residual alkalinity) / 183 x volume to be treated = the volume of CRS to add. Where alkalinity is as CaCO3.

This gives (156 - 30) / 183 x 30 = 21.7mL. This assumes 30 is the required residual alkalinity. No fancy calculator required.

So assuming you are still treating 30L and want 30 residual alkalinity then:

(137 -30) / 183 x 30 = 17.5 mL

Why not use Graham Wheeler's calculator given above under JBK links - brewing calculators - Graham's water treatment calculator

Graham's water treatment calculator

Do not put anything in the box marked hardness

[MattGuk]

Hi WallyBrew, thanks for your reply.
The volume treated on this current batch is only 20L of water as I will carry out a sparge.
I will use the calculator on this site as I must I have up on brewers friend.
Will the calculation that you gave me, what does the 183 represent?
Water chemistry is somewhat of a new path for me and I am struggling to know what residual alkalinity is ideal for each beer style.

[WallyBrew]

183 is the number of milligrams of calcium carbonate that 1mL of CRS will react with (neutralise).

[Silver_Is_Money]

20L x 137 mg/L Alkalinity (as CaCO3) = 2,740 mg

2,740 mg/50.04345 mg/mEq = 54.752 mEq's of Alkalinity (as CaCO3)

Acid strength of CRS = 3.66 mEq/mL

54.752/3.66 = ~15 mL of CRS required (rounded)

15 mL should get you to about pH 4.3. To hit around pH 5.4, add 90% of 15 mL, or 13.5 mL of CRS.

[Silver_Is_Money]

2740/183 ~= 15 mL (rounded) of CRS to hit ~pH 4.3

Again, add ~90% of 15 mL to hit ~ pH 5.4

[WallyBrew]

20L x 137 mg/L Alkalinity (as CaCO3) = 2,740 mg

2,740 mg/50.04345 mg/mEq = 54.752 mEq's of Alkalinity (as CaCO3)

Acid strength of CRS = 3.66 mEq/mL

54.752/3.66 = ~15 mL of CRS required (rounded)

15 mL should get you to about pH 4.3. To hit around pH 5.4, add 90% of 15 mL, or 13.5 mL of CRS.

Why take a simple calculation and make it more complex?
I doubt Matt has any idea what a mEq is and why would one want to aim for an arbitrary pH when one can work on the residual alkalinity which has long been British practice and has stood the test of time.

[MattGuk]

Thanks for the replies guys, that other calculation, while much appreciated, is definitely something I can't get my head around lol.
So 183 will always be constant factor when doing the calculation?

[Silver_Is_Money]

RA, or Residual Alkalinity, is a contrived value that rests solely upon the conception of 3.5 mEq's of Calcium neutralizing 1 mEq of Alkalinity (as CaCO3). This as determined in the 1930's by Kolbach.

Very recent research by Barth and Zaman has totally debunked this, as their research indicates that the divisor of 3.5 isn't even close to correct during the mash. In fact (for the specific malts they tested) they concluded that the 3.5 divisor must be replaced by 14.8 for Pilsner malt, by 7.2 for Pale malt, and by 12.2 for Munich malt. Effectively there is therefore no such thing as Residual Alkalinity. All of their detailed research destroying Kolbach's contentions with regard to Residual Alkalinity can be found within their peer reviewed dissertation titled:

'Influence of Strike Water Alkalinity and Hardness on Mash pH', by Roger Barth and Rameez Zaman

As found in:

(2015) Journal of the American Society of Brewing Chemists: Vol. 73, No. 3, pp. 240-242

[WallyBrew]

Residual is a word meaning that which remains after the greater bulk has gone and in this respect it is that which remains after neutralising the amount of alkalinity that one does not want and has nothing whatsoever to do with Kolbach and his calculation. In this respect the residual alkalinity is real and therefore exists.

[Silver_Is_Money]

Residual is a word meaning that which remains after the greater bulk has gone and in this respect it is that which remains after neutralising the amount of alkalinity that one does not want and has nothing whatsoever to do with Kolbach and his calculation. In this respect the residual alkalinity is real and therefore exists.

Fully agree for the case of water with Alkalinity, but that shouldn't technically be referred to as Residual Alkalinity, as it confuses things with the work of Kolbach. It is better referred to merely as remaining Alkalinity post acidification. And it may or may not guide any given grist into the ideal mash pH window.

That said, I do find it interesting that recent testing has shown that additions of calcium have far less downward impact upon mash pH than has been presumed for many decades. As I understand it, a downward shift more commensurate with Kolbach eventually occurs during the boil. This makes sense, because Kolbach never measured the pH drop caused by calcium or magnesium during the mash. He measured the drop at knock-out, post boil. We now know that much of it does not happen within the mash, and the bulk of it occurs during the boil.

[MattGuk]

So just a quick update, refilled this morning with 31.6 L of water as I have decided to carry out no sparge instead.
Check my Alkalinity again and was 142ppm before reduction.
Used the water treatment calculator here and selected 30 for residual alkalinity and it figured out I need 18.9ml of CRS which is what I have added.
No after re-checking my alkalinity I have 13.3ppm instead of 30.
I know its not and exact science but will this be ok?

[WallyBrew]

I know its not and exact science but will this be ok?

Yes but if you are happy with your 13mg/L you could pull 3 litres of the water and put 3 litres of untreated back in and you'll be at around 30.

This assumes you are using mainly pale malt and no large amounts of coloured malts.