What is Residual Alkalinity?

"RA"? I get the impression it's now much maligned and discredited? But John Palmer (author of "Water: A Comprehensive Guide for Brewers") still talks about it. I get the impression he's updated the original meaning to be a little less "abstract"?



It's a term for Brewers only, but how is that "3.5" calculated? It isn't a constant because it's a value created from "Mash Ration and Crush"; "Crush" obviously means grain crush (in what ... mm?), but what's the "Ratio"; grain and water? ... ?

Mr Palmer still rabbits about "Hardness", probably so as not to upset the people that still believe "Hardness" is a vital parameter in brewing. I don't care who I upset, we do not need "Hardness" and I'll blame Mr Palmer for perpetuating the idea in peoples' heads that "Hardness" is a vital parameter in brewing.

Anyway, less of that, I want to play about with this "RA" stuff, so, how is that "3.5" (mentioned above) arrived at, and how is "Magnesium also reacts, but about half as much" arrived at (the "half" bit)?

Using those numbers as-is (i.e. "3.5" and "0.5") the "RA" of my water resolves to: "-8.3 as CaCO3".

Oooh. Not quite sure what I'm going to do with that yet ...

An exerp from Palmers book on water (though I see no relation to malt crush and I’m unsure what’s meant by mash ratio). You can at least see where the 3.5 and 1/2 mg fit.

I can’t say I’ve made any effort to understand it because I’ve coped without it so far but if it helps…

peebee said:

Using those numbers as-is (i.e. "3.5" and "0.5") the "RA" of my water resolves to: "-8.3 as CaCO3".

Oooh. Not quite sure what I'm going to do with that yet ...

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A negative RA means the pH will be lower than a mash with distilled water, I don’t understand it well enough to say by how much. Sorry!

Bumping this along a bit ... I'm not sure we do have to be concerned about "RA".



(These slides Mr Palmer puts out are very useful for avoiding some typing).

RA relates directly to beer colour in this illustration. Notice too ... no "Hardness"! Mr Palmer is well aware that "Hardness" is an un-necessary complication to brewers (the place for "Hardness" is simply labelled "Calcium"). But unlike me, he prefers to ease brewers away from "Hardness" (I'm all for saying "stop being so daft" ... and generally making myself unpopular).

I'll simplify this diagram and turn it into a better known 2D triangular chart (three axis) ...

Meanwhile. Most British beer (traditional especially) seems to fall into "Firm* Structure, Amber or Dark Colour, Balanced or Malty Flavour". Just 4 of the 27 blocks. No wonder some of us had difficulty comprehending this stuff. Seems it has more to say about sociology than beer? It's good to see how it could possibly expand to more contemporary beers. Still, I'll keep studying it.


* Mr Palmer said he could only think of two "Firm" beers, the virtually unheard of "Burton Ale" and a meaty German "lager". I think I could add a few to that; "Firm" equates with higher amounts of Calcium ... 150ppm or so?

[EDIT: Spelling mistakes fixed.]

Hazelwood Brewery said:

A negative RA means the pH will be lower than a mash with distilled water, I don’t understand it well enough to say by how much. Sorry!

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Not 'arf! I'm usually struggling to get a pH above 5.0!

I'm hoping this extra study will explain why I'm left with mash pHs of 5.0. Seems I'm getting a glimmer of reasons why? Going back many months I began looking for the answer ... and as a result, achieved notoriety by developing the "Defuddller"!!!

Maybe I'm getting warmer in my search?

[EDIT: "Defuddler" has been updated by-the-way. Purged some of the errors in the "help" narrative but still needs more documentation of new features plus some tidying up for "cross-platform" display ... It's very demanding looking after such a thing ... and when half the community seemingly hates you for doing it too!!!]

[EDIT2: Correct bad grammar in Edit1. There's no end to it. A "Perfect Storm" of Maths and Grammer is swirling in me 'ead. And to think I thought I'd left it behind when I left school! And when was that ... don't ask!]

peebee said:

Not 'arf! I'm usually struggling to get a pH above 5.0!

I'm hoping this extra study will explain why I'm left with mash pHs of 5.0. Seems I'm getting a glimmer of reasons why?

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There are clearly a number of factors at play from your source water with it’s own buffering system through your water treatments and the derived RA to mash chemistry with phosphates and melanoidins.

peebee said:

Going back many months I began looking for the answer ... and as a result, achieved notoriety by developing the "Defuddller"!!!

It's very demanding looking after such a thing ... and when half the community seeming to hate you for doing it too!!!]

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Pretty much everyone that questions established wisdom or tries to make it more accessible to others faces the ire of those with vested interests. Who knows, maybe you’re on the cusp of discovering something big!

I'm back!

I'm not going to question "established wisdom". I'll do what I usually do and question many peoples' interpretation of established wisdom! And I know my interpretation needed questioning which is why I started this thread. Because I'm criticised for making simple subjects (?) complicated, I'll have to try particularly hard.



Residual Alkalinity, or "RA". Now that's a complex subject? ... No, it's not! Beer can be made very happily without knowledge of "RA", but it adds some interesting possibilities to creating beer recipes (or modifying others' recipes). So, I'll start with (and virtually finish with!) Paul Kolbach's empirical formula:

mEq/L Residual Alkalinity = mEq/L Alkalinity - (mEq/L Ca)/3.5 - (mEq/L Mg)/7

(I emphasis "empirical" because Mr Kolbach created this formula from observed results, not theory, and that might be important when trying to figure it out).

First thing to notice ... this has nothing to do with "Hardness". This pleases me, because I, as everyone should appreciate by now, despise "Hardness"! It's responsible for so much complexity and daft ideas from the brewing community we're better off without it (leave it to that handful of users who can understand it, or for judging if your new kettle will get furry or not).

Second. Argg! It's those spiky "mEq/L"! ""Milliequivalents per Litre". They're not so tough, it's just the usual "milligrams per Litre" that has undergone a couple of "transformations" so everything is the same and doing any sums on 'em is easier (you may have heard of "common denominator" ... it's much the same).

So, you can now read that "formula" like a book: Residual Alkalinity is the "Actual" Alkalinity in the water less the amount that substance "one" consumed in the mash, and less the amount that substance "two" consumed in the mash. Substance "One" will consume its own amount divided by 3.5 of the "Alkalinities", but Substance "Two" can only consume half as much for the same weight ... or divide it by "7" (two x 3.5).

Whippee! I've got a RA number! It's minus-0.14mEq/L. That's -7ppm as CaCO3 if you must have it in those arcane units.


I'll look at what I can do with this at a later date. Sorry if the post comes over a bit "condescending", but I'm pretty well practiced at that tone ... having suffered a bit of a bang on the head (12 years ago!) I have to get used to it!

peebee said:

Whippee! I've got a RA number! It's minus-0.14mEq/L. That's -7ppm as CaCO3 if you must have it in those arcane units.

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You missed the bit where you show your workings

Hazelwood Brewery said:

You missed the bit where you show your workings

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Don't need to! The "Defuddler" that calculated it is now so mind-boggling complicated that I dare not question its calculations. With all these RAF machines whizzing about overhead I worry that the "Defuddler" might organise an "accident" over my house.

It's calculated RA of my water as -7.0 ppm as CaCO3, but a week ago said it was -8.3 ... do you think I'm going to tell it?

peebee said:

The "Defuddler" that calculated it is now so mind-boggling complicated

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I am struggling with that sentence.

peebee said:

Don't need to!

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Yeh but you could, and you know you want to

Hazelwood Brewery said:

You missed the bit where you show your workings

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... Gmpha-phripp ...

Galena said:

Yeh but you could, and you know you want to

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... grrr ... nnn...Okay!

"Atomic Weight" of Calcium Carbonate is 100 (actually, the tiniest smidge more at 100.09), Valence of Calcium and Carbonate ions is 2. "Milliequivalents per Litre" of 1mg/L Calcium Carbonate is 1/2*100 = 50. All "Milliequivalents per Litre" of any ionic substance is calculated in this way, Calcium "atomic weight" is 40 and Carbonate atomic weight" is 60. 1/2*40=20, 1/2*60=30 ... 20+30=50. Cor! Not every substance has such convenient atomic weights, hence folk used "Calcium Carbonate" as an "equivalence".

So, my "Resideral Alkalinity" came to -0.14mEq/L. Of what? Doesn't matter, milliequivalents are the same whatever you work with (hence "equivalents"). So, -0.14mEq/L as "Calcium Carbonate"? -0.14/2*100 = -7.0 "as CaCO3". Blinding!

=============================================================================================

The other way of doing it. Remember that equation of Paul Kolbach's?

mEq/L Residual Alkalinity = mEq/L Alkalinity - (mEq/L Ca)/3.5 - (mEq/L Mg)/7

Using the Lenntech calculator:


Now we can convert to "as CaCO3" ... I got this out of the popular "Brew Your Own" ("BYO") magazine (2023!):

Residual alkalinity [°dH] = (bicarbonate concentration [mg/L] x 0.046) – (calcium concentration [mg/L] x 0.04) – (magnesium concentration [mg/L] x 0.033)

"German degrees of Hardness" (°dH) ... Ah well:

0.046 X 9.14mg/l HCO3 - 0.04 x 21.74mg/l Ca - 0.033 x 1.13mg/l Mg = (0.42044 - 0.8696 - 0.03729) "as °dH" = -0.48645°dH

Hum, doesn't add up. Well, this is only an illustration and I'm not hunting for less than 2mg/l! As Calcium Carbonate that is (which it isn't).

Thing is, I'm accused of making things complicated! That was an illustration of people not making it complicated? What makes things complicated is peoples insistence of (mis)using "Hardness"! MAKE YOUR LIFE EASIER ... STOP USING HARDNESS!!! IT (or the misuse of) is the real reason for complexity. There is no need for it, so don't use it.


[EDIT: The forum software is doing something screwy with my last sentence (can't see the "no"). Let's see if this fixes it ...]

https://beerandgardeningjournal.com/easy-aqua/

You need to search a bit, but this is one of the simplest and pragmatical articles about mineral additions. No need to understand or calculate RA.

Chris Colby is a real scientist.

peebee said:

"Atomic Weight" of Calcium Carbonate is 100 (actually, the tiniest smidge more at 100.09),

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How can we hope to work this out if you keep contradicting yourself

Murphy's would agree with you

Hardness can be a confusing term when used in brewing as it contains interrelated subgroups which have different impacts on the process. For this reason, we will deliberately not mention it in this guide (apart from in the title as Alkaline Water-Easy solution isn’t as catchy).

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MashBag said:

How can we hope to work this out if you keep contradicting yourself

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I do?

...

Oh. It's all right. A contradiction of nothing is ... nothing?

Now fill in any blanks you seem to have "forgotten"?

Galena said:

Murphy's would agree with you

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Thanks,

"Interrelated subgroups"? Heck. I'm not a patch on Murphy's am I.

chthon said:

https://beerandgardeningjournal.com/easy-aqua/

You need to search a bit, but this is one of the simplest and pragmatical articles about mineral additions. No need to understand or calculate RA.

Chris Colby is a real scientist.

Click to expand...

"Pragmatic" seems to describe it well. But don't be turned off "RA" because of the reams of cr** written over it (by other people with not a clue). It really is straightforward, something I'm only appreciating in the last few days (look for that "reading formula like a book" post I did earlier). There's got to be some possibilities in it somewhere ... I'll keep working on it.

"Chris Colby is a real scientist" ... err, that's a bit subjective and about as useful as @MashBag's nothing about nothing post. I guess I'm a "real" scientist 'cos I got an "A" at Chemistry "O" level ... and an "E" at Chemistry "A" level

But I'm not being a "scientist", more like an "evangelist"? (e.g. ... Say "no" to "Water Hardness").

When you said "You need to search a bit" ... there is more if I go looking?

[Off Subject Public Announcement]
Must say though I'm getting a bit fed up with Google and it's advertising at the expense of being able to read what they're hosting. I already view in "In-Private Mode" which at least gets rid of the Chinese cr** with scantily clad computer enhanced ladies, but I still get this:



Doesn't make for easy reading! But ... is this what the browser's "Imersive Reader" is for? Hooray!


[/Off Subject Public Announcement]

As an idea of what I have in mind with this "RA" stuff:

John Palmer puts out a whole load of stuff on "RA" including an illustration of how it might appear on a graph. He chose a 3D "Rubik Cube" style graph to put it on. I thought it could be done on a 2D three axis (triangular) graph, but it wasn't possible (triangular graphs need a common connection in which all three shared a proportion of the total, I was sure there would be one but there was not, or not that I could find). So, I pulled one axis out and displayed it separately ... another common way of showing 3 axis together (in 2D). The example in this illustration is that water from Battle, Kent (used in the "Defuddler" spreadsheet as a "default").

The illustration is just the raw water with no additions (and doesn't look too good a choice as a result). Ca=33mg/l, Mg=6mg/l, Na=50mg/l, Cl=50mg/l, SO4=38mg/l, HCO3=119mg/l, NO3=3.5mg/l (the detail doesn't matter, it's only an example). The "RA" worked out as 1.45mEq/l. Beer Colour relates to RA, Flavour=SO4/Cl ratio, Structure=Calcium. Something else to play with, but I'll need to have it in a working package first.


At the moment, I'm intrigued where this "project" is taking me. I've never attempted to plot beer colour over such a large range before, or even considered it as relevant. Colour equates to "RA" because the darker coloured roast and caramel/crystal malts need more alkaline salts (which will also be responsible for "alkalinity") to neutralise the extra acidity of the malts. "RA" is only providing a (presumably) more accurate measure of that "alkalinity" than the measures outside of the mash. Add to these the other two alleged impacts of water on beer (flavour and "structure") and other conclusions, of perhaps a more "sociological" kind, can open up. Like "Craft Beer" seems to crop up in the left half (two-thirds) of the graph (full range of colour), British "traditional" beers ("Real Ale") might be placed more upper right quadrant (darker half of colours)?

That's all thinking on me feet, speculation, the real reason I'm doing this is to build a water profiler/builder that works across a wide range with no artificial barriers. "RA" was, for me, a surprising tool in that aim.

Or that's the plan. What else should I consider that's relevant?

"Real scientist": Chris Colby has a PhD in biology and undergraduate degrees in biology and chemistry :-p.

About the link: it links further to four articles about how to determine the amount of salts and acids in function of four ranges of beer color, but in a very practical way.

It looks, if you want to build something to calculate your minerals, that this four part series is a simpler way to start with. It is already more or less algorithmic in nature.