Adjusting Ion balance and alkalinity using HCl and H2SO4

[MartinHaworth]

Hi Folks,

Just ordered 2M HCl, and 1M H2SO4 from APC Pure (UK).

Some of the folks in Norwich Amateur Brewers reckon on using these acids to reduce alkalinity and balance ions all in one go. Our water here has a residual alkalinity of c230ppm, and Cl c50ppm, SO4 c50pp, Ca 125ppm - general figures representative of Norfolk.

That is to say, use H2SO4 to reduce the alkalinity on a hop forward beer, and HCl to reduce alkalinity on a malt forwards beer. Or a blend for a more nuanced approach....

So, the question.

Whilst there are calculators online for this kind of thing, I kind of like to understand how it all works.

So, can any of your lovely brewers point me to resources on this...or even better explain it here!

Thanks

Martin

 

[strange-steve]

Good question, and yes your fellow brewers are correct. Using separate acids is a good way of gaining more control over the mineral of your water.

When sulphuric acid reacts with bicarbonate in the water it leaves behind sulphate, which is often added to hoppy beers in the form of gypsum. Hydrochloric acid on the other hand adds chloride, which is often added in the form of calcium chloride to enhance malty beers

CRS is a blend of hydrochloric and sulphuric acids with a fixed ratio which to some extent limits your control over the mineral content. (Lactic and phosphoric acids add neither sulphate nor chloride, but there are other potential issues with them.)

The molarity of the acids tells you how many moles there are per litre, so your 2M hydrochloric acid contains 2 moles (or 72.9g) of HCl per litre and your 1M sulphuric acid contains 1 mole (or 98g) of H2SO4 per litre. From this you can work out both the alkalinity reduction and the sulphate or chloride increase per unit volume.

Take the 2M hydrochloric acid first, 1ml contains 2mmol, which is 72.9mg, 2mg of which is H+ and 70.9mg of which is chloride (Cl-). One mole of HCl will neutralise one mole of bicarbonate, so 1ml of your 2M acid added to 1L of water will remove 122ppm (2mmol) of bicarbonate and increase the Chloride by 70.9ppm.

Your 1M sulphuric acid, 1ml contains 98mg, 2mg of which is H+ and 96mg of which is sulphate (SO4-2), and one mole neutralises 2 moles of bicarbonate. So 1ml of your 1M acid acid to 1L of water will remove 122ppm (2mmol) of bicarbonate and add 96ppm of sulphate.

Edit: I'm pretty sure those sums are right, but Cunningham's law says that no doubt someone will correct me if not

 

[MartinHaworth]

Good question, and yes your fellow brewers are correct. Using separate acids is a good way of gaining more control over the mineral of your water.

When sulphuric acid reacts with bicarbonate in the water it leaves behind sulphate, which is often added to hoppy beers in the form of gypsum. Hydrochloric acid on the other hand adds chloride, which is often added in the form of calcium chloride to enhance malty beers

CRS is a blend of hydrochloric and sulphuric acids with a fixed ratio which to some extent limits your control over the mineral content. (Lactic and phosphoric acids add neither sulphate nor chloride, but there are other potential issues with them.)

The molarity of the acids tells you how many moles there are per litre, so your 2M hydrochloric acid contains 2 moles (or 72.9g) of HCl per litre and your 1M sulphuric acid contains 1 mole (or 98g) of H2SO4 per litre. From this you can work out both the alkalinity reduction and the sulphate or chloride increase per unit volume.

Take the 2M hydrochloric acid first, 1ml contains 2mmol, which is 72.9mg, 2mg of which is H+ and 70.9mg of which is chloride (Cl-). One mole of HCl will neutralise one mole of bicarbonate, so 1ml of your 2M acid added to 1L of water will remove 122ppm (2mmol) of bicarbonate and increase the Chloride by 70.9ppm.

Your 1M sulphuric acid, 1ml contains 98mg, 2mg of which is H+ and 96mg of which is sulphate (SO4-2), and one mole neutralises 2 moles of bicarbonate. So 1ml of your 1M acid acid to 1L of water will remove 122ppm (2mmol) of bicarbonate and add 96ppm of sulphate.

Edit: I'm pretty sure those sums are right, but Cunningham's law says that no doubt someone will correct me if not

BOOM! That is just so helpful. It is exactly what I needed to know.

I'd got the molar values of HCl and H2SO4, but then got stuck with the chemistry.

But I have followed you splitting up the weights into the ions, AND just about followed the reaction and ion changes (assuming avagadro constant was the factor). I'll spend some time putting these values into formulae and post them here later if you could check them please?

Another question....James Morton reckons that if Cl- levels get above 300ppm, then the beer can end up unbalanced - Would you agree
Also, I've heard mixed views on maximum SO4-2 levels. Opinions?

Thanks again

Martin

 

[strange-steve]

I'll spend some time putting these values into formulae and post them here later if you could check them please?

No problem thumb

question....James Morton reckons that if Cl- levels get above 300ppm, then the beer can end up unbalanced - Would you agree
Also, I've heard mixed views on maximum SO4-2 levels. Opinions?

The question of upper limits is one that crops up often, but the answers can be wildly different depending on who you ask. But I think it's fair to say that many UK brewers are of the opinion that the danger of "minerally tasting" beer is very much overstated by our American counterparts, especially when discussing British styles.

Personally I haven't went as high as 300ppm chloride so I can't really comment but I have been gradually increasing the amount I use, and must say I'm liking the results so far. My next porter or stout I might try somewhere near 300ppm as a personal experiment.

Wrt sulphate, personally I wouldn't go much higher than about 250ppm or so because I'm not really into that dryness you get from it, but again others go considerably higher than that. It really comes down to personal taste which means some trial and error might be involved in finding your preference.

 

[MartinHaworth]

OK. Thanks again @strange-steve

So, as I understand it, with these two acids at their different strengths, if I add 1ml/L I will be taking out 122ppm of residual alkalinity.

In addition, each 1ml/L of HCl will add 70.9ppm of Cl-. Each 1ml/L of H2SO4 will add 96ppm of SO4-2.

Great. Now that I have this, I think I'm happy to trust the calculators.

But just for shits and giggles, a worked example.

Starting with Norwich water: residual alkalinity of c230ppm, and Cl c50ppm, SO4 c50pp, Ca 125ppm

Pale hoppy beer, full length mash (30l), sulphate forward 2:1. Want residual alkalinity of 30ppm.

So 30L of liquor will need (200/122)*30 = 49.18ml of acid.

Aha! But which acids to get the 2:1 I need.

If I use all H2SO4 I will end up with almost a 3:1 ratio. This is not what I am looking for.

But if I use one fifth HCl, this will bump up the Chloride by (70.9/5) 14.2ppm to a total of 64ppm. And I use four fifths H2SO4, this will bump up the Sulphate by (0.8*96) 76.8ppm to a total of 127ppm.

And here I have my 2:1 ratio.

So, I will use a blend of 4/5 sulphuric (39.3ml) and 1/5 hydrochloric (9.8ml) for this beer.

Happy Days?

Thanks

Martin

 

[strange-steve]

OK. Thanks again @strange-steve

So, as I understand it, with these two acids at their different strengths, if I add 1ml/L I will be taking out 122ppm of residual alkalinity.

In addition, each 1ml/L of HCl will add 70.9ppm of Cl-. Each 1ml/L of H2SO4 will add 96ppm of SO4-2.

Great. Now that I have this, I think I'm happy to trust the calculators.

But just for shits and giggles, a worked example.

Starting with Norwich water: residual alkalinity of c230ppm, and Cl c50ppm, SO4 c50pp, Ca 125ppm

Pale hoppy beer, full length mash (30l), sulphate forward 2:1. Want residual alkalinity of 30ppm.

So 30L of liquor will need (200/122)*30 = 49.18ml of acid.

Aha! But which acids to get the 2:1 I need.

If I use all H2SO4 I will end up with almost a 3:1 ratio. This is not what I am looking for.

But if I use one fifth HCl, this will bump up the Chloride by (70.9/5) 14.2ppm to a total of 64ppm. And I use four fifths H2SO4, this will bump up the Sulphate by (0.8*96) 76.8ppm to a total of 127ppm.

And here I have my 2:1 ratio.

So, I will use a blend of 4/5 sulphuric (39.3ml) and 1/5 hydrochloric (9.8ml) for this beer.

Happy Days?

Thanks

Martin

Your calculations are correct with one important exception. The acids at 1ml/L reduce bicarbonate by 122ppm, rather than alkalinity as CaCO3. There is a simple conversion though, divide bicarbonate by 1.22, meaning that the reduction at 1ml/L is 100ppm of alkalinity as CaCO3.

Which brings me to another point, you mentioned that your water has a residual alkalinity of 230ppm. Just be careful there because residual alkalinity is a mash-specific term which takes into consideration acidification due to calcium and magnesium, and it's not a value that would be specified by a water supplier. It's not the same as alkalinity as CaCO3 which is the commonly used unit for brewers. Residual alkalinity complicates matters and should probably be ignored, at least initially.

One other thing, it might be a good idea to get a Salifert KH kit to test for alkalinity yourself. This will also allow you to check that the sums are correct by taking a few litres of water, testing the alkalinity, adding a known amount of acid, and retesting.

 

[MartinHaworth]

Your calculations are correct with one important exception. The acids at 1ml/L reduce bicarbonate by 122ppm, rather than alkalinity as CaCO3. There is a simple conversion though, divide bicarbonate by 1.22, meaning that the reduction at 1ml/L is 100ppm of alkalinity as CaCO3.

Which brings me to another point, you mentioned that your water has a residual alkalinity of 230ppm. Just be careful there because residual alkalinity is a mash-specific term which takes into consideration acidification due to calcium and magnesium, and it's not a value that would be specified by a water supplier. It's not the same as alkalinity as CaCO3 which is the commonly used unit for brewers. Residual alkalinity complicates matters and should probably be ignored, at least initially.

One other thing, it might be a good idea to get a Salifert KH kit to test for alkalinity yourself. This will also allow you to check that the sums are correct by taking a few litres of water, testing the alkalinity, adding a known amount of acid, and retesting.

Thanks so much. I will recalculate accordingly! Actually, 1ml/L to reduce by 100ppm is really easy to remember...

Cheers, Martin

 

[MartinHaworth]

Here we go...if i get this right it can go in the reference bit of my brew log! A print off of this lovely thread. Two small changes based on bicarb/alkalinity correction.

Using 2M Hcl and 1M H2SO4.

So, as I understand it, with these two acids at their different strengths, if I add 1ml/L I will be taking out 100ppm of alkalinity.

In addition, each 1ml/L of HCl will add 70.9ppm of Cl-. Each 1ml/L of H2SO4 will add 96ppm of SO4-2.


Worked example

Starting with Norwich water: residual alkalinity of c230ppm, and Cl c50ppm, SO4 c50pp, Ca 125ppm

Pale hoppy beer, full length mash (30l), sulphate forward 2:1. Want residual alkalinity of 30ppm.

So 30L of liquor will need (200/100)*30 = 60ml of acid.

Aha! But which acids to get the 2:1 I need.

If I use all H2SO4 I will end up with almost a 3:1 ratio. This is not what I am looking for.

But if I use one fifth HCl, this will bump up the Chloride by (70.9/5) 14.2ppm to a total of 64ppm. And I use four fifths H2SO4, this will bump up the Sulphate by (0.8*96) 76.8ppm to a total of 127ppm.

And here I have my 2:1 ratio. 12ml HCl, 48ml H2SO4.

@strange-steve you have been very helpful, and I am grateful. Can I put a bottle of my Abbey Dubbel in the post to you?

Thanks

Martin

 

[strange-steve]

Almost there, but your maths are a little off. It's good up until this part:

"But if I use one fifth HCl, this will bump up the Chloride by (70.9/5) 14.2ppm to a total of 64ppm. And I use four fifths H2SO4, this will bump up the Sulphate by (0.8*96) 76.8ppm to a total of 127ppm."

Don't forget that if you're using 60ml of acid in 30L of water then you're actually using 2ml/L, whereas you've used values for 1ml/L. So the correction would be to double the increases like so:

But if I use one fifth HCl, this will bump up the Chloride by (141.8/5) 28.4ppm to a total of 78.4ppm. And I use four fifths H2SO4, this will bump up the Sulphate by (0.8*192) 153.6ppm to a total of 203.6ppm.

However this throws your ratio off again to 2.6, rather than 2, but if you change the acid proportions to 18ml hydrochloric and 42ml sulphuric you'll end up with 92.5ppm chloride and 184ppm sulphate with your 2:1 ratio thumb

Edit: There is a formula which will tell you how much acid to add to hit your target ratio while taking into account the chloride and sulphate already present, but my maths isn't good enough to work that out right now.

Also, where are you getting that alkalinity value of 230ppm?

 

[MartinHaworth]

alkalinity value from phoenix analytical. Across the city the club are checking alkalinity very regularly and it is stable at this value +-10ppm across the year,