The importance of Alkalinity?

[Galena]

I have a recipe for a beer which I am advised te original has a water alkalinity of around 100ppm with a mash pH of 5.3, all things considered how important is it to hit the alkalinity when making additions, my water is only 15ppm as CaCO3. Forgetting the other parts of the water profile for a minute, how much will the alkalinity play in getting the flavour or feel like the beer I am aiming for as against just worrying about the pH?

 

[foxbat]

Is it a black beer by any chance? The relatively high acid content in black malts could call for water with a high alkalinity level to balance the pH in the mash. If you really want to brew it accurately you could get some cheap supermarket water to cut with your tap water. I think the cheap stuff is relatively high in alkalinity but you'd have to check the label.

 

[Galena]

Is it a black beer by any chance? The relatively high acid content in black malts could call for water with a high alkalinity level to balance the pH in the mash. If you really want to brew it accurately you could get some cheap supermarket water to cut with your tap water. I think the cheap stuff is relatively high in alkalinity but you'd have to check the label.

No it is dark ruby red, about 49 EBC, the point though is the brewers tap water has an alkalinity of about 300ppm, they reduce it with acid to get it to about 100ppm to get the pH down to 5.3. So my question really is, if I get my pH to 5.3 but my alkalinity is much lower, what will the difference be so far as the beer goes or should I use some slaked lime to push it up, which I can easily do.?

 

[strange-steve]

So my question really is, if I get my pH to 5.3 but my alkalinity is much lower, what will the difference be so far as the beer goes

The thing is you won't get a mash pH of 5.3 with a lower alkalinity, because alkalinity adjustment is the method used to hit a specific pH (in theory at least). So if you don't adjust your alkalinity you'll probably have a pH which is too low, and this may possibly cause flavour issues later down the line.

The easiest way for you to add 85ppm of alkalinity would be to add 0.14g/L of sodium bicarbonate (baking soda).

 

[Galena]

The thing is you won't get a mash pH of 5.3 with a lower alkalinity, because alkalinity adjustment is the method used to hit a specific pH (in theory at least). So if you don't adjust your alkalinity you'll probably have a pH which is too low, and this may possibly cause flavour issues later down the line.

The easiest way for you to add 85ppm of alkalinity would be to add 0.14g/L of sodium bicarbonate (baking soda).

But I do have a mash pH of 5.3, or just a little over with an alkalinity of 15, in fact (according to Brewfather) I need to add 0.6mls to a 21L batch to get it down to 5.3 at 15ppm alkalinity of my tap water. If I add either Baking Soda or Slaked Lime then I can get my alkalinity up to 100 but as can be expected that pushes my pH up as well.
Now if I add lactic acid I can bring the pH back down to 5.3 but this does not reduce the alkalinity (according to Brewfather) something doesn't seem right there though I would expect reducing the pH to also reduce alkalinity, or am I confusing myself?

 

[strange-steve]

OK I think we are in fact getting a bit confused, so let's star at the beginning. If I'm reading your post correctly the recipe you're following recommends 100ppm alkalinity and a mash pH of 5.3. Now these two things are inextricably linked, a higher alkalinity will lead to a higher mash pH, so presumably whoever wrote the recipe used water with 100ppm alkalinity and measured his mash pH as 5.3.

If I understand your question correctly you want to know whether you should target the alkalinity or the mash pH. Theoretically if your grain bill, alkalinity, and mash ratio are the same, then your pH should also be the same. However it seems that you've inputted the details into a mash calculator and it has said otherwise?

There are several possible explanations for this. Firstly, remember that no mash prediction software is 100% accurate, which is OK because as long as the pH is within a few 10ths of 5.5 then it should be good enough. Another factor that could cause a difference is calcium, which also reduces pH during the mash, so if your mash water has a much different calcium level to that used by the recipe writer then it could have a different pH.

To answer your question then (as I've understood it) you should adjust your alkalinity so that your estimated mash pH, according to your preferred calculator is 5.5 or thereabouts (this is my personal preference for a target because it gives a bit of wiggle room either way). Don't worry about the alkalinity as a separate variable, as I said it is simply the thing we adjust in order to hit the correct pH.

 

[Galena]

Thank you @strange-steve sorry if I am being a bit slow on the uptake, but am I correct in assuming that adding lactic acid will not reduce alkalinity because the ions that create that alkalininity will still be there regardless of acid additions? Therefore I can target increasing alkalinity by adding baking soda or slaked lime and also reduce pH by adding acid?

Fort example:

Here is my tap water profile:
Ca: 21.3, Mg: 2.9, Na: 9.3, Cl: 12.5, SO4: 31.3, Alkalinity as CaCO3: 15 (HCo3: 18)

My target profile is
Ca: 140, Mg: 10, Na: 9, Cl: 75, SO4: 227, HCO3: 120

By additions of 9.8g Gypsum, 4.2g CaCl2, 2.3g MgSO4 and then increase alkalinity with 1.5g Ca(OH)2 gives me:
Ca: 152, Mg: 10, Na: 75, SO4: 227, HCO3: 94

which is close enough to my target, however, this leaves my pH at 5.45 so if I add 2.7 mls lactic acid it brings it down to 5.3 and the alkalinity remains at 94.
Alternatively I can leave out the Ca(OH)2 addition and reduce my lactic acid a little and still have a pH of 5.3 but my alkalinity is now 15

So my question, I guess is is the above correct and how much difference will I tell between the two?

 

[foxbat]

I wish I had your tap water. It's perfect for pilsners and other pale lagers with very little adjustment.

 

[Galena]

I wish I had your tap water. It's perfect for pilsners and other pale lagers with very little adjustment.

It is, I don't drink either though unless under duress though I may be tempted to try a Pilsner soon for the wife when I can free a brew fridge up for long enough.

 

[strange-steve]

am I correct in assuming that adding lactic acid will not reduce alkalinity because the ions that create that alkalininity will still be there regardless of acid additions? Therefore I can target increasing alkalinity by adding baking soda or slaked lime and also reduce pH by adding acid?

No, adding acid to water reduces both alkalinity and pH. The alkalinity determines how much the pH will drop, high alkalinity means only a small change in pH, low alkalinity means a large change in pH. This is because bicarbonate, the ion predominantly responsible for alkalinity in water, reacts with hydrogen ions from the acid to form H2O and CO2.

In other words, increasing the alkalinity of your water and then adding lactic acid is pointless because they are working in opposition, you'll end up back where you started (but with some lactate and sodium left behind).

The reason we use alkalinity when talking about brewing water is because it is the best way to estimate what the mash pH will be. If the alkalinity is too high then the mash pH will also be too high and vice versa. That's all, alkalinity in isolation from pH is irrelevant. The two are inextricably linked, so we typically have a target alkalinity for our mash which will hopefully get us into the correct pH range. Presumably that's why the recipe states 100ppm alkalinity, but that should only be a rough guide and may not be accurate for your particular water profile.

Since you're using a calculator, whatever alkalinity results in the correct estimated pH, that is the correct alkalinity to use.

 

[Galena]

Since you're using a calculator, whatever alkalinity results in the correct estimated pH, that is the correct alkalinity to use.

Many thanks for your explanations, it's quite a learning curve just when I thought I was getting a hang of it. Another school day though, so great stuff.

 

[peebee]

You (@Galena) are one of a small percentage of folk for who this "modern" fascination with "alkalinity" makes no sense at all. Nothing you do in practice seems to make any useful advance in understanding it. With very little effort the results seem to come out right; the calculators predict a pH outcome and you can make minor adjustments to tweak the pH where you want.

I'm in this position. I'll have 60 litres of sparge water to which I'll add less than 1ml of 81% Phosphoric Acid and the pH drops from 7.5 - 8.5 to less than 5.5 (which effectively means no alkalinity left at all - and you can then ignore the worries of leaching tannins and like when sparging).

You're then in that hazardous situation, as I was, of saying "what's the use of all this alkalinity nonsense"? Where upon the other 90+% of brewers put you right: It wont be pretty and you probably will still not get an answer to your original question. But you will know not to say such things again! The other sore subject you can start is using slaked lime to increase pH - that enters a whole warren of rabbit holes you can fall down.


If really unlucky, isolated in this balloon of no "alkalinity" worries, you can fall foul of things like inability to get mash pH above 5.0 (I've gone through two of these periods). You can't find the answer, and everyone on these forums ignore your cries for help: 'Cos they haven't got a clue what you are talking about.

 

[strange-steve]

Cos they haven't got a clue what you are talking about.

Ironically I have no idea what the point of this post is. Whether your alkalinity is high or low you can still adjust it to manipulate mash pH. My tap water is similar to the OPs with around 25ppm alkalinity, and I adjust it upwards with sodium bicarbonate when I brew dark beers (which is what I mostly brew). If you find your mash pH is too low then add more alkalinity next time. With a little trial and error I can't see what's complicated about that.

 

[peebee]

Ironically I have no idea what the point of this post is. …

The point is ... why bother with something as mind-numbing as "Alkalinity" (and as a concept it is mind-numbing when you are one of the minority where understanding it doesn't help one jot) when you can ignore it, use the calculators and (usually) add a gram of two of bicarbonate and/or slaked lime, or even a ml or two of phosphoric acid (that might get some howls of protest).

"Alkalinity" is all about the water's resistance to changing pH downwards. When the water don't contain enough of anything to significantly resist changing anything, then there is no need to look for something to make the process more complicated.

Even you have spread the cloak of "Alkalinity" to encompass the trial and error of adding some alkaline salts (e.g. bicarbonate) to get the pH right. Actually I found the trial and error bit to be "which calculator comes up with the right answers for my circumstances".

My earlier post was to warn @Galena away from stating "what's the point with this Alkalinity malarky?" and have the vast majority of brewer's come down on him like a ton of bricks. Unfortunately I'm putting myself in the firing line for getting it in the neck. Just to make it worse I'll add that I added 6g of slaked lime to my mash last weekend (the 44L of water already had 5g sodium bicarbonate added) - let me see if anyone tells me what great misfortune adding that much lime to my mash will have had (the pH obviously went down, not up, for one; and all the Calcium will have disappeared).



But so that this isn't just a whinging post, I'll put in this piccie that certainly helped me come to terms with this "Alkalinity" caper (no commentary, so folk will have to think a while to understand what it's saying, but do note one thing: there's no CaCO3 in water of pH8.4ish or lower - or maybe two; there is no "Alkalinity" below pH 4.3ish):

 

[strange-steve]

why bother with something as mind-numbing as "Alkalinity"... when you can ignore it, use the calculators and (usually) add a gram of two of bicarbonate and/or slaked lime

This is sort of what I recommended in post 6 above: "you should adjust your alkalinity so that your estimated mash pH, according to your preferred calculator is 5.5 or thereabouts... don't worry about the alkalinity as a separate variable".

There are two common ways of trying to hit a proper mash pH:

1. Adjust the alkalinity to an appropriate range depending on the beer colour (not entirely accurate but simple and usually effective).
2. Stick all your details into a calculator and make the recommended adjustments to get a proper estimated mash pH (probably more accurate but also more complicated, especially for newbies).

But both of these methods utilise alkalinity adjustment, whether it's understood or not. You say "ignore (alkalinity) and add a gram or two of bicarbonate", but by adding said bicarbonate you are not ignoring it, you are adjusting it.

I think what you are suggesting to the OP is to ignore the complex theory of alkalinity, which is fine, but that could be said of all aspects of brewing. Whatever you do don't ask why mash temperature is important, just ignore it and aim for the temperature suggested in the recipe.

But then on the other hand, perhaps at least a basic understanding of brewing concepts and principles might be beneficial? I took the OP to be asking a genuine question rather than a rhetorical "why bother?" and rather than "coming down on him like a ton of bricks" I tried to answer it to the best of my (admittedly limited) understanding. After all isn't what forums are for?

 

[peebee]

This is sort of what I recommended in post 6 above: "you should adjust your alkalinity so that your estimated mash pH, according to your preferred calculator is 5.5 or thereabouts... don't worry about the alkalinity as a separate variable". ...

You did too! Okay, apologies. But it was just that I was trying to warn @Galena from. Your status around here obviously protects you from un-necessary criticism (except from me, but I've had a bang on the 'ead and can say what I like to whoever I like!). If I advise to just use pH and ignore all the "Alkalinity" bumph, I get pounced on by dozens of folk wanting to tear their own strip off me (not this forum, a different one).

So, given >this<, (the "confused with basicity" bit); how do you get away with it? :tinhat: (You don't need to answer that, or if you do, you can just PM me!).

I had to learn all this nonsense because I was being eaten alive for my views, yet, as I said earlier, the understanding doesn't help me brew beer one jot. (Nor would it explain the periods of very low mash pH I go through occasionally; nor would my critics explain it either - 'cos they probably didn't know). So my compromise is I accept I'm subject to envious water quality, but the majority have to suffer all this "Alkalinity" babble.

 

[strange-steve]

Your status around here obviously protects you from un-necessary criticism

Status?? What status is that?
I'm very far from an expert on this stuff, and have never claimed to be one. I simply find it interesting and try my best to understand it, and when I think I gain some sort of understanding (superficial as that may be) I like to share it in some attempt to help others understand what is potentially a very complex subject. Protected from criticism? Definitely not, I'm happy to be corrected when I'm wrong and nobody is above criticism, least of all me.

folk wanting to tear their own strip off me (not this forum, a different one).

Yes I'm aware :tinhat:

So, given >this<, (the "confused with basicity" bit); how do you get away with it? :tinhat: (You don't need to answer that, or if you do, you can just PM me!).

I want to answer it but I'm not entirely sure what you're getting at? I think you're saying I've confused alkalinity and basicity? Yes adding bicarbonate to the water will increase basicity somewhat but it also increases the alkalinity, since bicarbonate is the ion primarily responsible for alkalinity. If I've gotten something wrong here then, as above, I'm happy to be corrected.

the understanding doesn't help me brew beer one jot.

Maybe so but you're not worse off for understanding it either. Surely more knowledge is always better than less?

Nor would it explain the periods of very low mash pH I go through occasionally; nor would my critics explain it either - 'cos they probably didn't know

I won't attempt to explain it either and won't pretend I can.

the majority have to suffer all this "Alkalinity" babble.

Ironic then that your attempts to save the OP from the alkalinity babble has led to even more...

 

[Galena]

If you will humour me for one more post on this, as I recall my original post simply asked if the alkalinity would affect flavour or feel of the beer. This got more complicated as it went on however my question is still a simple one and if you look at the two images perhaps it shows my main query a little better and where I am getting confused



If you look at the first image, there is no acid addition, the alkalinity is 98 and the pH is 5.49

In the second image, I have added 3.3mls lactic acid and as you will see in the image below the alkalinity is still 98 but the pH is now 5.3

So, my question is simply, is this correct or incorrect and an issue in the software? If it is correct will I notice any difference in the beer?

 

[strange-steve]

So, my question is simply, is this correct or incorrect and an issue in the software?

It's just a quirk of the software, the alkalinity displayed as 98ppm is the pre-acidification value and it doesn't display the post-acid alkalinity because when using a calculator that's irrelevant. It shows you the reduction in pH from the acid which is what you are targeting.

You're over complicating this, but I'll say again, forget alkalinity as a separate entity. It is only useful to us as it relates to mash pH. The only reason to target a specific alkalinity is to ensure a proper mash pH, therefore if the pH estimate is good without any alkalinity adjustment (ie without any acid or bicarbonate) then you don't need to adjust it.

In practical terms then, input your base water profile and the grain bill into your calculator. Add enough gypsum and/or calcium chloride to get about 100ppm of calcium. Now what is the predicted mash pH? If it's a little low then add a touch of bicarbonate until the pH is good. If it's a little high add some lactic acid until it's good. It's as simple as that.

 

[peebee]

… Ironic then that your attempts to save the OP from the alkalinity babble has led to even more...

You're right.

And @Galena proves it by prattling on more about "Alkalinity". Perhaps your last post saying "forget alkalinity" will get through. That's just the phrase I got "flamed" for. @Galena doesn't seem to get he's one of the less than 10% UK brewers that understanding "Alkalinity" will do zilch for.

"Alkalinity" is an un-necessary diversion. I wonder if that remark will get me a "flaming" I expect from the 90%+ of other UK brewers?


To answer @Galena's question directly: "Alkalinity" doesn't make a difference to your beer, but mash pH might. "Alkalinity" and pH might be linked, but it's nowt for you to worry about; pity others for having to do that. Just get your pH right.

P.S. @Stange-steve mentions lactic acid. I've used Phosphoric Acid. But I've only done it once (anaemic "American" style water profile) and you'll use so little (less than 1ml in a 25L batch I did) you could get away with battery acid if crazy enough.