Ro or tap

[PeeBee]

… See the third paragraph of Note 9? …

The "add to mash, not the water" trick. Personally I was suspicious of this as you have no idea what you've actually done (can't see it <EDIT: of course I "can't see it" … I should have made it clearer that I'm talking "figuratively">). But if you have the confidence then not a problem (if Graham was still about we'd have the confidence - he could be "very persuasive"!).

Which is a point: You should add calcium hydroxide (mentioned by "Silver_Is_Money") to the mash, not the water, too, but for an entirely different reason which I hope we don't have to go over again (the forum's "instructor" on this that comes to my mind isn't so much "persuasive" as "abusive").

I noticed Graham mentioned "sodium carbonate" in his "Note 9" but didn't think it was such a good idea. I do use sodium bicarbonate (it does dissolve - I'm one of the minority UK homebrewers who does need to add alkalinity to his water and to increase the pH) but am of the belief "sodium carbonate" will dissociate into sodium and bicarbonate in the mash anyway? Sodium bicarbonate (baking soda) is much easier to get your hands on.

[guypettigrew]

Indeed it (Graham's calculator) is excellent, and there is undeniably nothing else like it, but it has a serious Achilles heel. It relies heavily upon calcium carbonate, and it presumes that calcium carbonate both fully dissolves and dissociates into ions, just as for other calcium species such as gypsum and calcium chloride.

How does Graham's calculator rely heavily on Calcium Carbonate, please?

In all the time I've been using it, not once has it asked me to add Calcium Carbonate.

Guy

[PeeBee]

Reducing the alkalinity of highly alkaline source water via slaked lime treatment, …

Ah, guess my warning was too late. Well it had to be really. I find this works (user control panel tweak), but its only valid for your own forum view:

******, who is currently on your ignore list, made this post.

[killer]

Reducing the alkalinity of highly alkaline source water via slaked lime treatment, and lowering mash pH via the same are two distinctly different subjects.

In the mash calcium hydroxide both raises and lowers mash pH simultaneously. The Ca++ calcium ion component complexes with malt phosphates to liberate H+ ions (thus lowering the pH) while simultaneously the OH- hydroxyl ion component is raising mash pH. The latter effect is more predominant than the former, so the net effect is that mash pH gets raised, albeit less than if the added calcium is not accounted for. The very same would be true for CaCO3 (if it was soluble). If there was no mash pH lowering effect due to the calcium component of calcium hydroxide, then 0.44 grams of calcium hydroxide would raise alkalinity to the same degree as 1.0 gram of baking soda. But due to the calcium effect it takes more on the order of ~0.618 grams of calcium hydroxide to raise the alkalinity of the mash to the same measure as for 1.0 gram of baking soda.

I’m not disagreeing with the theory, but it is one thing to debate the finer points of Carbonate equilibria, solubility, and dissociation constants on an online forum in a comfy armchair than to be a bleary eyed homebrewer/ professional brewer adding Calcium Hydroxide to a Hot Liquor tank at 6AM in the morning - and those are the people using water calculators.
I have come across a number of breweries brewing Russian Imperial Stouts using a double mash system. Two of these breweries knew that they needed an alkalinity of at least 300 ppm for the first mash. In attempting to raise their liquor alkalinity from ~200 ppm to 300 ppm using slaked lime and following the instructions in Brunwater they managed to do the opposite and lower it significantly, which gave low mash and low pre-and post-fermentation pHs.
That is what I’m warning against – the average brewer adding salts (somewhat blindly) based on a free online calculator.

[Silver_Is_Money]

How does Graham's calculator rely heavily on Calcium Carbonate, please?

In all the time I've been using it, not once has it asked me to add Calcium Carbonate.

Guy

Perhaps I've missed something. What other alkalinity raising chemical(s) does it offer to achieve raising alkalinity?

Have you ever needed to raise a waters alkalinity while using Graham's calculator?

[Silver_Is_Money]

I have come across a number of breweries brewing Russian Imperial Stouts using a double mash system. Two of these breweries knew that they needed an alkalinity of at least 300 ppm for the first mash. In attempting to raise their liquor alkalinity from ~200 ppm to 300 ppm using slaked lime and following the instructions in Brunwater they managed to do the opposite and lower it significantly, which gave low mash and low pre-and post-fermentation pHs.
That is what I’m warning against – the average brewer adding salts (somewhat blindly) based on a free online calculator.

Kolbach discovered way back in the 1930's that it requires 3.5 mEq's of calcium ions to reduce 1 mEq of alkalinity within the mash (and as an aside, 7 mEq's of magnesium ions to do likewise). If you are adding Ca(OH)2, and the two OH- ions which it liberates are nearly fully mEq for mEq efficacious in raising the alkalinity (being only very slightly dissociation constant hindered), while at the same time the Ca++ ions equal number of mEq's must be divided by 3.5 and are thereby greatly hindered in their ability to lower alkalinity, then how can adding Ca(OH)2 to the mash ever lower the mash pH?

[WallyBrew]

In attempting to raise their liquor alkalinity from ~200 ppm to 300 ppm using slaked lime and following the instructions in Brunwater they managed to do the opposite and lower it significantly, which gave low mash and low pre-and post-fermentation pHs.

I do not use Bru'nwater but as Killer has stated the brewers were and this requires adding it to the mash liquor.
This is not the same as

how can adding Ca(OH)2 to the mash ever lower the mash pH?

adding slaked lime to a water that already has a high level of alkalinity will induce the process of calcium carbonate precipitation and the rate at which this proceeds does not seem to be a constant so the expected alkalinity may well be lower than that expected.

[Silver_Is_Money]

Part of the problem with Bru'n Water may be that (from memory) it calculates that within the mash adding about 0.55 grams of Ca(OH)2 should yield the equivalent in mash pH raising effect as for adding 1 gram of baking soda. I've computed (as stated on the previous page) that the need here is for about 0.618 grams of Ca(OH)2 to raise mash pH to the equivalent degree as for 1 gram of baking soda. I compute a need for 12.36% more Ca(OH)2. Pending upon who (if either of us) is more correct here, the net effect of using BW to compute the requisite addition of Ca(OH)2 to hit a desired mash pH target is inevitably going to to end with a lower mash pH than expected.

[Silver_Is_Money]

adding slaked lime to a water that already has a high level of alkalinity will induce the process of calcium carbonate precipitation and the rate at which this proceeds does not seem to be a constant so the expected alkalinity may well be lower than that expected.

I can definitely see this as a consequence of specifically adding the Ca(OH)2 to already high alkalinity (plus high Calcium ion) mash water in advance of brew day. It intuitively seems therefore that to minimize this effect one attempting to raise the alkalinity of already high alkalinity water should add Ca(OH)2 directly to the mash. But then I've always stated that intuition alone often makes for bad science.

[WallyBrew]

KHCO3 is the answer

[killer]

I have come across a number of breweries brewing Russian Imperial Stouts using a double mash system. Two of these breweries knew that they needed an alkalinity of at least 300 ppm for the first mash. In attempting to raise their liquor alkalinity from ~200 ppm to 300 ppm using slaked lime and following the instructions in Brunwater they managed to do the opposite and lower it significantly, which gave low mash and low pre-and post-fermentation pHs.
That is what I’m warning against – the average brewer adding salts (somewhat blindly) based on a free online calculator.

Kolbach discovered way back in the 1930's that it requires 3.5 mEq's of calcium ions to reduce 1 mEq of alkalinity within the mash (and as an aside, 7 mEq's of magnesium ions to do likewise). If you are adding Ca(OH)2, and the two OH- ions which it liberates are nearly fully mEq for mEq efficacious in raising the alkalinity (being only very slightly dissociation constant hindered), while at the same time the Ca++ ions equal number of mEq's must be divided by 3.5 and are thereby greatly hindered in their ability to lower alkalinity, then how can adding Ca(OH)2 to the mash ever lower the mash pH?

As Wallybrew has mentioned they were adding salts to the Hot Liquor Tank. So by adding the Slaked lime they increased the liquor pH and shifted the Carbonate equilibrium to the Calcium Carbonate form and the alkalinity precipitated. Transferring the resultant liquor to the mash vessel meant that their mash pH was very low.

I've seen this a few times now.

[guypettigrew]

How does Graham's calculator rely heavily on Calcium Carbonate, please?

In all the time I've been using it, not once has it asked me to add Calcium Carbonate.

Guy

Perhaps I've missed something. What other alkalinity raising chemical(s) does it offer to achieve raising alkalinity?

Have you ever needed to raise a waters alkalinity while using Graham's calculator?

Ah, that would be it, then.

My alkalinity is about 200ppm and I always need to lower it, never raise it.

Guy

[Silver_Is_Money]

If anyone is interested, here is how I came up with 0.618 grams of Ca(OH)2 as the pH raising equivalent of 1 gram of baking soda:

MW of Ca(OH)2 = 74.09268, so therefore the Eq Wt of Ca(OH)2 = 37.0463 (due to the charge or valence of 2)
MW of NaHCO3 = 84.0066, so its Eq weight is also 84.0066 (since charge or valence is 1)

37.0463/84.0066 = 0.440993

If there was no calcium ion downward impact upon mash pH shift, then 0.440993 grams of Ca(OH)2 would be the alkalinity and thereby pH raising equivalent of 1 gram of baking soda.

But every 1 mEq of added OH- from Ca(OH)2 brings along with it an equal 1 mEq of Ca++ (due to molecular cation/anion balance)

Per Kolbach it takes 3.5 mEq's of Ca++ to reduce 1 mEq of alkalinity.

1/3.5 = 0.2857 mEq of alkalinity reduction due to the calcium ion present within Ca(OH)2.

As a consequence of this, 0.2857 more Eq Wt of Ca(OH)2 is required.

But then this corrective addition brings along with it 0.2857/3.5 = 0.08163 mEq's of alkalinity reduction, etc..., etc..., so on and so on, ad-infinitum.

This infinite chain can be represented mathematically as 1 + 0.2857 + 0.2857^2 + 0.2857^3 + 0.2857^4, + 0.3857^5 ... etc..., whereby 1 is the initial need for 0.440993 x baking soda, and the rest are needed additions of OH- mEq's to counter the calcium that comes with it each time, adding to infinity.

Solving for this gives:

1 + 0.2857 + 0.2857^2 + 0.2857^3 + 0.2857^4 + 0.2857^5 ... = ~1.39921 (plus a minuscule scooch more to account for the infinity part left off here)

So ultimately, to counter the pH reduction of its own calcium, and to bring equivalence to baking sodas pH rise in the mash, one must add:

0.440993 x 1.39921 = 0.617 grams of Ca(OH)2 for every calculated 1 gram of baking soda required (plus a minuscule scooch more). Call it ~0.618 grams.

So by solving an infinite equation the mash pH raising mEq equivalent of Ca(OH)2 to baking soda yields ~0.618 grams of Ca(OH)2 for every calculated gram of baking soda. Leaving aside their dissociation constant effects, ~0.618 grams of Ca(OH)2 should raise mash pH by the same amount as 1 gram of baking soda.

[guypettigrew]

Fascinating, but brain aching stuff!

Reminds me of why I loved chemistry at school, but could never get on with higher mathematics.

Dare I ask, what do you do in real life?

Guy

[Silver_Is_Money]

Fascinating, but brain aching stuff!

Reminds me of why I loved chemistry at school, but could never get on with higher mathematics.

Dare I ask, what do you do in real life?

Guy

Retired. 42 years in the chemical industry. Much of it as a scheduler and then as a buyer/planner. Now I finally get to use my education. But I've forgotten more than I remember.