Does any serious brewer use Malic, Tartaric, Citric or Acetic acids?

[bitteritdown]

Does any serious brewer use Malic, Tartaric, Citric or Acetic acids to neutralize alkalinity and/or control mash pH?

If so, what effects do they have on the final product?

 

[ajdelange]

When home brewing was in its infancy many recipes called for citric acid.

 

[cire]

Does any serious brewer use Malic, Tartaric, Citric or Acetic acids to neutralize alkalinity and/or control mash pH?

If so, what effects do they have on the final product?

Not that I know of. Once I used citric acid to reduce a proportion of alkalinity for a brew some years ago. It did have a slight citric taste and wasn't one of my best brews, but it can't be said that was entirely due to the citric acid.

In the minutes of a discussion amongst a group of British brewers more than 100 years since, it was queried why more organic acid was required than with mineral acids. Once I titrated a sample of my tapwater with 5% acetic acid to observe an ever diminishing reduction in pH and gave up as it seemed it would never reach 4.5. Phosphoric acid can be observed to have a similar effect but not anywhere near the same degree. I think it's buffering.

 

[SanPancho]

citric can be used to adjust final ph on hoppy beers. brings out the hop flavors a bit

 

[ajdelange]

why more organic acid was required than with mineral acids. Once I titrated a sample of my tapwater with 5% acetic acid to observe an ever diminishing reduction in pH and gave up as it seemed it would never reach 4.5. Phosphoric acid can be observed to have a similar effect but not anywhere near the same degree.

The amount of alkalinity that can be neutralized by an acid, per mole, depends on the number of protons the acid has to release and the pK associated with each of those protons relative to the target pH. Sulfuric acid has two protons and the pK for the first is less than 0 and for the second it is 1.92. Both of these are well less than 5.4 and so each mole of sulfuric acid releases almost 2 equivalents of protons when used to acidify to mash pH. Citric acid has three protons with pK's of 3.14, 4.77 and 6.39. The first two are less than pH 5.4 but the second not so much as the first so not all citric acid molecules will release the second proton. On average, citric acid releases 1.94 protons per molecule to pH 5.4. Phosphoric acid has 3 protons to donate with pKs of 2,145, 7.2 and 12.44. It releases, on average 1.016 protons per molecule to pH 5.4. Hydrochloric acid has a single proton and with a pK < 0. To pH 5.4 effectively all protons are released i.e. 1 per molecule. Lactic acid has but a single proton with pK = 3.86. This is less than 5.4 but not by that much. The average molecule of lactic acid therefore releases 0.97 protons.

Thus, in terms of ability to reduce alkalinity per mole, mineral sulfuric acid is in first place with organic citric in second followed by mineral phosphoric followed by mineral hydrochloric with organic lactic behind that.

With respect to acetic acid: there is a single proton with pK 4.76. Little surprise that you never got to 4.5 using acetic though you would have eventually.

We've learned a few things in the last 100 years.

 

[cire]

The amount of alkalinity that can be neutralized by an acid, per mole, depends on the number of protons the acid has to release and the pK associated with each of those protons relative to the target pH. Sulfuric acid has two protons and the pK for the first is less than 0 and for the second it is 1.92. Both of these are well less than 5.4 and so each mole of sulfuric acid releases almost 2 equivalents of protons when used to acidify to mash pH. Citric acid has three protons with pK's of 3.14, 4.77 and 6.39. The first two are less than pH 5.4 but the second not so much as the first so not all citric acid molecules will release the second proton. On average, citric acid releases 1.94 protons per molecule to pH 5.4. Phosphoric acid has 3 protons to donate with pKs of 2,145, 7.2 and 12.44. It releases, on average 1.016 protons per molecule to pH 5.4. Hydrochloric acid has a single proton and with a pK < 0. To pH 5.4 effectively all protons are released i.e. 1 per molecule. Lactic acid has but a single proton with pK = 3.86. This is less than 5.4 but not by that much. The average molecule of lactic acid therefore releases 0.97 protons.

Thus, in terms of ability to reduce alkalinity per mole, mineral sulfuric acid is in first place with organic citric in second followed by mineral phosphoric followed by mineral hydrochloric with organic lactic behind that.

With respect to acetic acid: there is a single proton with pK 4.76. Little surprise that you never got to 4.5 using acetic though you would have eventually.

We've learned a few things in the last 100 years.

Thank you for that. However, your reply suggests there will be a linear progression which I have always found with hydrochloric and sulphuric acids. Initially with acetic acid the fall in measured pH was similar to those recorded using mineral acids, but as pH approached 5.0, instead of the fall accelerating it did the opposite with an ever decreasing fall. Was I doing something wrong?

 

[myndflyte]

Thank you for that. However, your reply suggests there will be a linear progression which I have always found with hydrochloric and sulphuric acids. Initially with acetic acid the fall in measured pH was similar to those recorded using mineral acids, but as pH approached 5.0, instead of the fall accelerating it did the opposite with an ever decreasing fall. Was I doing something wrong?

No you didn't do something wrong. The pKa is not where pH will change the fastest. See the titration curve here: https://images.tutorvista.com/cms/images/101/pKa-of-acetic-acid.png

 

[mabrungard]

I don't know of many brewers that dabble in using those acids. But they can be used to add nuances to your brews without relying on natural organisms to supply those anions. For example, acetic acid is a minor component of brett fermentations. But venturing down that avenue and introducing that bug into your brewery might be worrisome for many. The same thing can be said for the fruity nuances provided by those other organic acids. Hard to get that in beer, but it might be desirable in some styles.

 

[ajdelange]

Thank you for that. However, your reply suggests there will be a linear progression

I certainly didn't mean to imply that. It is quite non linear. The curve below supposes you have a liter of tap water at pH 9 which has an alkalinity of 1.07 mEq/L. The vertical axis shows the mmol of phosphoric acid which must be added to attain the pH values shown on the x axis.

As you can see it takes relatively little acid to lower the pH from 9 to 7.3 relative to what it takes to get from 7.3 to mash pH.

...which I have always found with hydrochloric and sulphuric acids.

That shouldn't have been the case as it is essentially the first pK of carbonic acid (6.38) that is controlling here (it's not coincidence that the curve crosses 0.5 acid addition at 6.38).

Initially with acetic acid the fall in measured pH was similar to those recorded using mineral acids, but as pH approached 5.0, instead of the fall accelerating it did the opposite with an ever decreasing fall.

That is normal. You should see the pH initially drop quite fast then slow and then accelerate again depending on the pK's. The example curve above starts to heel over a bit at low pH because phosphoric acid is a 'weak' acid. With a strong acid (sulfuric, hydrochloric) it would heel over much more becoming nearly flat.

Was I doing something wrong?

That appears to be the case.

 

[cire]

I certainly didn't mean to imply that. It is quite non linear. The curve below supposes you have a liter of tap water at pH 9 which has an alkalinity of 1.07 mEq/L. The vertical axis shows the mmol of phosphoric acid which must be added to attain the pH values shown on the x axis.

Sorry, the confusion is again mine with the meaning of the term "linear progression" and that you have gone through a great amount of work to correct my understanding.

I'm not a chemist, but have been involved with brewing one way and another for more than 50 years. The linearity I meant was not of the rate of change of pH, but that of the quantity of alkalinity eliminated by acid additions to water containing naturally occuring alkalinity. (I am familliar with the titration curves of strong and weak acids.) Acids sold by British brewing supplies companies are supplied with datasheets advising the rate of use rather than in terms of molarity or other measurement as will be seen in this example.
https://www.murphyandson.co.uk/Datasheets/AMS.pdf

Using mineral acids such as AMS or sulphuric and hydrochloric I found that the rate of reduction in alkalinity (I initialy wrote this in terms of the residual alkalinity which would also be interpreted differently) was consistent and therefore what I described as linear. However, when doing the same with acetic acid, it appeared that the rate of reduction of alkalinity diminished as more acid was added and was therefore in that sense not linear. This made me assume that chlorides and sulphates provide less buffering than actetates and gave a reason for brewers of ales to conclude they needed more of an organic acid to achieve a similar result when using a mineral acid when brewing.

 

[ajdelange]

Sorry, the confusion is again mine with the meaning of the term "linear progression" and that you have gone through a great amount of work to correct my understanding.

I'm not a chemist, but have been involved with brewing one way and another for more than 50 years.

Please don't apologize. I too am long in the tooth and use exercises like this one to keep the rust out of the mental hinges. Nor am I a chemist.

The linearity I meant was not of the rate of change of pH, but that of the quantity of alkalinity eliminated by acid additions to water containing naturally occuring alkalinity.

I posed it in terms of more acid being required to get less pH shift at lower pH but it could also be posed in terms that say that the same amount of acid dispatches less alkalinity at lower pH.

Acids sold by British brewing supplies companies are supplied with datasheets advising the rate of use rather than in terms of molarity or other measurement as will be seen in this example.

In so doing they are effectively specifying the normality of the acid WRT mash pH. I used molarity in the illustrations because the molarity of the acid is constant whatever the pH. Thus, if you have 1 M acid you can consider the vertical axis in the plot to read mL 1 M phosphoric acid. The curve then shows that it takes more mL of acid at low pH to get the same shift in pH than it does at higher pH.

Using mineral acids such as AMS or sulphuric and hydrochloric I found that the rate of reduction in alkalinity (I initialy wrote this in terms of the residual alkalinity which would also be interpreted differently) was consistent and therefore what I described as linear. However, when doing the same with acetic acid, it appeared that the rate of reduction of alkalinity diminished as more acid was added and was therefore in that sense not linear.

The curve for the same water using acetic acid is given below. Interpret the vertical axis as mL of 1 M acetic acid if you like. It is plain from this that indeed more acid is required to reach pH 5.4 with acetic than phosphoric but it is when you strive to acidify to a pH less than the pK of acetic acid that things turn a bit more dramatic.

This made me assume that chlorides and sulphates provide less buffering than actetates

Acids provide appreciable buffering near their pK's. Thus in the picture above the curve is steepest at 6.38 (the first pK of carbonic which we are modeling as the main source of alkalinity with a smidgeon from OH-) and near 4.77, the pK of acetic acid. It is these two pKs (and the amounts of carbonic and acetic acid in the mix) which determine the pH. As the pK of acetic acid is close to mash pH there is going to be some buffering from acetate if acetic acid is used for pH adjustment. As the pKs of sulfuric and hydrochloric acids are remote from mash pH they will not provide appreciable buffering. Your assumption is correct.

and gave a reason for brewers of ales to conclude they needed more of an organic acid to achieve a similar result when using a mineral acid when brewing.

Their conclusion should be driven not by whether the acid is organic or mineral but by what its pK's are. It turns out that hydrochloric, sulfuric and phosphoric acids, all mineral, have pK's appreciably lower than mash pH and so are strong when talking about mash pH but, as we showed in the previous post, organic citric is second only to sulfuric beating out mineral phosphoric and hydrochloric.

 

[ajdelange]

From the AMS data sheet linked in No. 10:

35ml of AMS per hl of this water reduces the alkalinity by 64 mg/litre (ppm) and increases chloride levels by 22.5 mg/litre (ppm) and sulphate levels by 31 mg/litre (ppm).
Knowing this information you can calculate the amount of AMS needed to reduce your alkalinity to the ideal level.

Yes we can because this is sufficient information to tell us what's in the product.

The chloride in 1 L of water is augmented by 22.5 mg/L which is 22.5/35.45 = 0.6347 mEq/L. The sulfate is augmented by 31 mg/L which is 31/48 = 0.6458 mEq/L. As both hydrochloric and sulfuric acid are strong with respect to mash pH we assume that the chloride and sulfate come from, respectively, those acids which would contribute hydrogen ions in quantity equal to the sum of the anion augmentation or 1.2805 mEq. They state that alkainity would be reduced by 64 mg/L which we assume to mean mg/L as CaCO3 in which case that means that 64/50 = 1.28 mEq/L protons have been supplied. As this is equal to the sum of the protons indicated by the chloride and sulfate increases we conclude that AMS is an equinormal (WRT mash pH) mix of hydrochloric and sulfuric acids. This is the same conclusion we had previously drawn regarding this product but from Murphy's tables and not this data sheet.

As the statment regards a hectolitre treated with 35 mL of the product we conclude that the hydrochloric normality, equal to the molarity, is about 100*0.6347/35 = 1.81 N (M) and that the sulfuric acid component is about 100*0.6458/35 = 1.85 N. As sulfuric acid is diprotic the molarity is half this. The normality of the solution tells us how much we need to use to handle a particular water. It is 100*1.2805/35 = 3.66 N.

Check: To eliminate 64 ppm alkalinity (1.28 mEq/L) from an hL of water we would need 100*1.28/3.66 = 34.97 mL.

In fact we don't need to eliminate all the alkalinity but only about 90% of it (this is because alkalinity is measured to pH 4.5 and we only need to get to mash pH) thus is we had a hL of water of alkalinity 64 ppm as CaCO3 we would only need 0.9*100*1.28/3.66 = 31.5 mL.

In case this isn't clear to determine how much AMS to add to treat carbonaceous water:
1)Convert alkalinity in ppm to mEq/L by dividing by 50 (multiply by 2 and shift the decimal two to the left)
2)Compute 90% of this and multiply by the volume (L) of water you are treating
3)Divide by 3.66

The answer from step 2 is the acid requirement in mEq/L. If you are using any other acid divide by the normality of that acid rather than the normality of AMS is step 3.
If you want to neutralize an amount of alkalinity other than 90% just convert the amount you want to nuetralize to mEq/L, multiply by the number of L and divide by 3.66.

Also from their spec sheet:

COMPOSITION An acidic aqueous solution of mineral salts

If there are indeed any additional salts in the product they are clearly not chlorides or sulfates which leaves ???

AMS adjusts liquor alkalinity without the need for boiling by removing unwanted carbonate ions and adding desirable ions, such as chloride and
sulphate in the correct ratios, ideal for most beer styles.

Apparently they have decided that the correct ratio is 22:31::Cl:SO4 which just happens to be the ratio attained when the mix is equinormal in the two acids. Coincidence?

 

[cire]

Murphy and Son are a law unto themselves, but their sales stratergy is effective.

It's pleasing to have one of Murphy's datasheets analysed rather than dismissed without a moment's thought. They can be error prone, many poor conversions from grains, gallons, pounds and ounces, quarts, bushels, pints, barrels and other unit not in common use today, but they contain other errors too. Despite this, Murphy's broad brush approach enables beer production that can be in a pub cellar two weeks from loading the mash tun and the empty cask returned for refill in three.

It appears many believe that British brewers actively reduced high mineral contents of their liquor supply while the greater proportion didn't and sold their beers on those merits.

Below is an example of the advice Murphy's give to their brewers. That below is for a homebrewer for a fee, but they will analyse water every three months for free for breweries with an account, supplying information similar to that below scaled to its capacity.

Their advice for darker ales might surprise more.

 

[ajdelange]

It appears many believe that British brewers actively reduced high mineral contents of their liquor supply while the greater proportion didn't and sold their beers on those merits.

I think many are aware what happens when 'mineral rich' water is heated to strike temperature.


Interesting that in the posted example at least that they recommend removing about 90% of the alkalinity of the source liquor.

 

[cire]

I think many are aware what happens when 'mineral rich' water is heated to strike temperature.


Interesting that in the posted example at least that they recommend removing about 90% of the alkalinity of the source liquor.

I think there are many unaware of beer styles made with mineral rich water.

The 90% is pure coincidence. Were the alkalinity level 90% less, they would advised no reduction.

 

[cire]

This other may help.

 

[ajdelange]

The amount of alkalinity that needs to be neutralized depends on the alkakinity and pH of the source, the targeted mash pH and, of course, the acidity/alkalinity of the grains. The answer does vary, of course, but falls near 90% surprisingly often. The recommendations of the second example would work (give an acceptable mash pH) if one had about 20 percent crystal and because of the 9 (yes 9!) mEq/L calcium they are recommending. Rather crunchy, I would think, but if the consumers like it (or think they like it) that's OK from the brewery's point of view. This does help me to understand the flight to lager though.

 

[cire]

This does help me to understand the flight to lager though.

Then I shan't spoil your day with Murphy's advised treatment for Lager.

 

[ajdelange]

Please do!

 

[MSK_Chess]

yes please do.

 

[cire]

Two for the price of one.

 

[ajdelange]

Thanks. Wonder why you thought this would spoil my day though. That is a lot of calcium for sure but not 9 mEq/L. Was that it?

They seem to want to get the calcium up there as they advocate the use of lactic acid for pH adjustment which I presume is done to allow calcium to go high without going too high in chloride and sulfate. The other thing I find interesting is that they advocate adding the HLac to the liquor but suggest mixing the calcium salts into the mash. I wonder why.

 

[dmtaylor]

I've used vinegar, added a "glug" or two to the mash. It works, and you cannot taste it in the final beer IF you don't overdo it.

 

[cire]

Thanks. Wonder why you thought this would spoil my day though. That is a lot of calcium for sure but not 9 mEq/L. Was that it?

Getting close.

They seem to want to get the calcium up there as they advocate the use of lactic acid for pH adjustment which I presume is done to allow calcium to go high without going too high in chloride and sulfate. The other thing I find interesting is that they advocate adding the HLac to the liquor but suggest mixing the calcium salts into the mash. I wonder why.

We've been there before. It's not particularly difficult to apply and prove that beer is made in more ways than some might care to think.

 

[ajdelange]

Where have we been before?

I don't recall any mention of alcohol assay in this thread but the term 'proofing' is usually reserved for discussion of distilled spirits (though the procedure is the same for beer and distilled spirits in the case where the latter suffers from high obscuration). [edit] No. 24, since edited, read 'proof', hence my response,[/edit]Nor do I recall anyone suggesting, here or anywhere else, for that matter, that beers are not made and have not been made in a virtually unlimited number of ways. I'm afraid I just don't understand what you are trying to say here.

 

[MSK_Chess]

Can someone explain why they are advocating such high mineral concentrations? Are they high? perhaps i have used a loaded question? Is it for the yeast, are they particularly mineral dependent? reason I ask if you go to brewlabs website they mention this parameter that some yeasts prefer a light mineral wort others a high mineral wort. Is it for taste perception? To enhance malt, hops? mouthfeel? I understand that to my palate mineral water with a lot of calcium in it has a kind of silky mouth feel, perhaps this is the reason? perhaps its a combination of all these things?

 

[ajdelange]

Calcium has lots of beneficial effects on beer. Among them are
a)Protects mashing enzymes from high temperature
b)Insures bright runoff
c)Reacts with phytin to produce H+ ions which lower mash pH into a more desirable range
d)Precipitates calcium oxalate thus reducing gushing (and kidney stones)
e)Promotes protein coagulation
f)Enzyme co factor
g)Enhances beer stability
f)Promotes yeast flocculation
g)Things I don't remember

Calcium is pretty flavor neutral but the anions that accompany it when it is added to beer, sulfate and chloride, are not and you can't add more calcium without adding more anion. So the price that must be paid for the benefits on the list are high levels of those cations. Of course sometimes those anions are desirable too. Many beers, like some of the ones being discussed here have what would ordinarily be considered high levels of calcium and, accordingly, sulfate and or chloride. For those beers where high level of sulfate and chloride are wanted one pretty much has to use the calcium salts as magnesium, sodium and potassium all have undesirable effect in high quantity and you don't get the benefits on the list from them. IOW, in those cases, calcium is along for the ride.

While those espousing high levels of calcium can certainly point to the benefits on the list the tone from the other side of the pond seems to be that these high levels are wanted because that's the way things are traditionally done for the traditional beers brewed over there. If you are interested in authentic beer in these styles, that's the way you do it.

 

[ajdelange]

We've been there before. It's not particularly difficult to apply and prove that beer is made in more ways than some might care to think.

Ah. I see from your edit that 'proof' was a typo for 'prove' but I still don't understand what it is we are going to apply to prove or disprove something that people we know nothing about may or may not think. ???

 

[cire]

Can someone explain why they are advocating such high mineral concentrations? Are they high? perhaps i have used a loaded question? Is it for the yeast, are they particularly mineral dependent? reason I ask if you go to brewlabs website they mention this parameter that some yeasts prefer a light mineral wort others a high mineral wort. Is it for taste perception? To enhance malt, hops? mouthfeel? I understand that to my palate mineral water with a lot of calcium in it has a kind of silky mouth feel, perhaps this is the reason? perhaps its a combination of all these things?

At the link below is a paper reviewing previous and present British Brewing Liquor Treatment in 1955. The entire paper is a worthy read, but the last paragraph on page 207 contains reference to calcium levels in times prior to and when it was written. There too you will see what was perhaps the first mention of sulphate:chloride ratios which is often taken out of context of the original which was written in relation to specific calcium levels.

Multiply grains per gallon by 14 to get ppm.

http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1955.tb02787.x/epdf

 

[user 246304]

Two for the price of one.

View attachment 560769

Fascinating. Kills me I probably can't get ahold of their products to try the regime out. One question I have, and it may be a noob question, but when they indicate the g/L of beer to be made, of the salts, to be added into the mash; I don't have the math in front of me but I presume the figures in green reflect this?

In other words, what I've done (until your suggestion, actually), is build a "cistern" where liquor is just liquor, for the whole brew. Acids and salts are in to get, say, TA=32, calcium, SO4, Cl to be at the level suggested. It looks like I should be adding these salts into the mash; the sparge water gets no salts; and the figures in green are for cast-volume of wort (i.e., batch size). Is this correct? Not ppm of the MLT or HLT liquor?