Phosphoric acid and calcium

[Morrisoff too]

For my last few brews I've been using CRS to get my carbonate levels down to an acceptable level. My water is 370 mg/l CaCO3 according to Murphys, 340-350 using a Salifert kit. Using CRS to get rid of that amount of carbonate gives me a rather high chloride level, so I decided to give phosphoric acid a go. I've been told by a professional brewer that I don't want to do that as it'll take out all my calcium and clog up my boiler element.

I tested a 1 litre batch. Tested the Ca level first using a Salifert calcium test (120), then added 0.44ml phosphoric, stirred, left for 30 mins and tested Ca again. Still 120. Boiled for 10 mins, cooled. Very heavy precipitate and nasty scale ring around saucepan. Took a sample from the clear water just under the surface, tested, still 120.

Would I be correct in thinking that the precipitate is actually from the carbonate and that the calcium level is the same because some has been released from from the carbonate?

I also did a 10 litre batch in my Buffalo boiler. Used a little more acid in that (0.5ml/l — enough for the Salifert alkalinity test to go pink with the first drop of reagent). Boiled for ten minutes and had beautifully clear water and no scale. How could that happen?

Thanks for any help. Really trying to get my head round all this stuff!

Cheers

[Aleman]

Despite people saying that phosphate does not precipitate calcium it is pretty obvious that it does. The precipitate is apatite which is a calcim phosphate. Your pro brewer is right ideally you need either sulphuric or hydrochloric acids so that you don't get such a severe precipitate when you neutralise your alkalinity

[Eric]

That's a remarkably high amount of alkalinity. Using CRS to reduce alkalinity by 300mg/l CaCO3 will increase chlorides by 106mg/l and sulphates by 144mg/l which although high, is not exceptionally so. At this moment I'm drinking a pale made from liquor containing 190mg/l sulphates and 176mg/l chlorides, bittered with Magnum using Saaz for aroma and while it's different, I'm finding it quite sublime.

Precipitate in the HLT from liquor treated with phosphoric acid is now becoming well documented. That acid is popular with brewers in USA where they are a major producer and is accordingly freely available, and their water generally will precipitate less, having less calcium and alkalinity than in geologically dissimilar locations with different weather patterns like the UK. The precipitate cannot be the carbonate component, that is liberated in the carbon dioxide and water products. The reaction of alkalinity with phosphoric acid is complex, I don't know what does for certain happen as there is more than one chemical composition of calcium phosphate and to further complicate matters, two thirds of phosphoric acid passes on into the finished beer, potentially as dihydrogen phosphate.

Ever thought of using sulphuric acid? Using it to remove alkalinity of 300mg/l CaCO3 would add 288mg/l sulphates and no chlorides. You could also use a mix of it and CRS.

[killer]

I would echo Eric comments with regard to Calcium phosphate. In the complex milieu that is beer wort, you will have an equilibrium of different salt forms. So while simple Calcium phosphate may indeed be pretty insoluble, when you add chlorides and sulfates and magnesium, you may have a whole range of salts of different solubility. I have never observed precipitation when I add phosphoric acid - and my water is quite hard. In contrast, boiling does precipitate a lot of Calcium carbonate - and I usually need to leave my liquor overnight in order to fully dissolve any gypsum that I add.

In any case, there does seem to be something wrong with your results. The addition of phosphoric acid will remove the bicarbonate. If there is no visual precipitate, then the calcium content should remain the same as the calcium is presumably still in solution. The observation of a precipitate upon boiling suggests that you are either precipitating Calcium Carbonate (common at elevated water temperatures) or the calcium phosphate. In either case the calcium levels should drop... Unless you waited so long that the minerals redissolved.

My own solution to reach my desired profiles is a blend of acids. I typically add CRS first - then phosphoric - then some salts.

Finally - how does your beer taste when using a lot of CRS - why are you switching to phosphate ?

[Morrisoff too]

Thanks for the replies.

I have considered using just sulphuric, but that does give me a very high sulphate content. I suppose I could try a mix of sulphuric and CRS to alter the sulphate/chloride balance more towards sulphate. Presumably if I did a 50:50 I could just average the results that brun water gives me for both scenarios?

The reason I want to try something else is that I think CRS gives me a slight minerally tang. I also think the high chloride level might be masking some hop crispness.

Think I'll try phosphoric for the next brew, which is just a using up leftovers affair, and see how it goes.

Cheers

[AnthonyUK]

I'm in a similar situation regarding bicarbonate levels and the best solution for me was to buy in suitable water e.g. Tesco Ashbeck at £1 per 5l.
You can use all bottled or dilute your own down to suit the style.

[Eric]

Thanks for the replies.

I have considered using just sulphuric, but that does give me a very high sulphate content. I suppose I could try a mix of sulphuric and CRS to alter the sulphate/chloride balance more towards sulphate. Presumably if I did a 50:50 I could just average the results that brun water gives me for both scenarios?

Do you know how much sulphate and chloride are in your water as supplied? I'm guessing they will not be vastly great as calcium at 120ppm can only provide up to 300ppm alkalinity, so unless your water like mine has a large amount of magnesium it's unlikely their quantities would be high.

The reason I want to try something else is that I think CRS gives me a slight minerally tang. I also think the high chloride level might be masking some hop crispness.

This is the problem with CRS, being of acids in a fixed ratio, when used in highly alkaline waters it can produce a wrong water profile. That said, try lactic acid with your level of alkalinity, it might just make you to give up drinking beer altogether. When you say you think chloride gives a minerally twang, is that because you can taste it or that Bru'nWater tells you it will? What is your opinion of the suggested water profiles and influences as Murphy and Son advise and can be read here? Have you found such profiles unsuitable? I think any flavour in a beer other than hops would in some way mask hoppines.

Think I'll try phosphoric for the next brew, which is just a using up leftovers affair, and see how it goes.

Cheers

Yes, you should try that acid to see how it goes, I have. Good Luck.

[Mr. Dripping]

I've switched over to phosphoric acid from CRS and my beers have improved immensely. My alkalinity is generally between 130-140ppm, and after throwing several batches of beer and doing a lot of reading I came to the conclusion that the CRS was the problem. My beers were extremely harsh and minerally....bordering on astringent. I had a sample tested by Murphys, which backed up my analysis on alkalinity but the beers were just wrong when I used CRS.
The switch to phosphoric acid (along with calcium sulphate and calcium chloride additions) and a good understanding of Bru'nWater has made the world of difference.
I would like to make some beers using sulphuric acid, but can't at the moment find a source of food grade acid.....if anyone can help here please post up details (thanks).

There is also a series of 4 or 5 BrewStrong podcasts where Jamil and JP talk at length to Martin Brungard about various aspects of water quality and adjustment for brewing.....these are well worth downloading and listening to.

[killer]

@ Mr. Dripping,

Murphy and sons do sell Sulfuric acid

http://www.murphyhomebrew.com/

[Eric]

I've switched over to phosphoric acid from CRS and my beers have improved immensely. My alkalinity is generally between 130-140ppm, and after throwing several batches of beer and doing a lot of reading I came to the conclusion that the CRS was the problem. My beers were extremely harsh and minerally....bordering on astringent. I had a sample tested by Murphys, which backed up my analysis on alkalinity but the beers were just wrong when I used CRS.
The switch to phosphoric acid (along with calcium sulphate and calcium chloride additions) and a good understanding of Bru'nWater has made the world of difference. I would like to make some beers using sulphuric acid, but can't at the moment find a source of food grade acid.....if anyone can help here please post up details (thanks)..

There is also a series of 4 or 5 BrewStrong podcasts where Jamil and JP talk at length to Martin Brungard about various aspects of water quality and adjustment for brewing.....these are well worth downloading and listening to.

When you consider how much sulphuric acid you would use for water with alkalinity of that range, it is questionable what quality it would need to be. Anyway, you might try this, but if you do, don't rely on what strength you are told.

Using Phosphoric acid then adding calcium sulphate and calcium chloride instead of CRS might simply achieve the same end except your beer would, after using phosphoric acid contain more phosphates including that of dihydrogen. CRS used to neutralise alkalinity will only introduce sulphates and chlorides to the finished beer. That said, with that level of alkalinity it is likely you might not be able to taste the resultant phosphates.

[Mr. Dripping]

Thanks for that killer and Eric.

I have been worried about calcium precipitates and other issues that could possibly be problematic now I'm using phosphoric acid.....but I have as yet found nothing negative. That's not to say they aren't there but my beer quality has jumped up so massively that maybe the leap forward is masking them??

From what you posted there Eric I guess you are saying the acid strength is not always what it says on the tin??

[Morrisoff too]

Hi Eric

Should have mentioned before. Mg is 25, sulphate 39, chloride 48.

How do you work out how much alk you have from calcium and magnesium figures?

I think I can taste it the CRS. There's definitely a taste there that I hadn't come across before.

Wow, those values (Murphy's link) are higher than I'm getting, and higher than I remember seeing anywhere else. Food for thought.

I've ordered some sulphuric and some AMS today so plenty of things to play with.

Cheers

[Eric]

Their technical data sheet can be seen via this link.
Despite trying, that information remains unchanged. Paul did provide the following picture as evidence of its properties, which in fact confirms the acid is not 25, but 35%.



The dosage rates given at the bottom of Murphy's datasheet might be for 25% sulphuric acid, but if you get what others and myself got, you will use less acid. This isn't a problem if you measure your liquor's alkalinity after acid treatment, but not everybody does. I know one head brewer who uses that product with those figures in combination with his water report. His beers aren't that bad (which makes you wonder why all the fuss about mash pH) I've drank worse, made worse, but my local won't stock his products.

0.5 pint of their acid per brewer's barrel is 1 part in 576 and is said to reduce alkalinity by 508mg/l CaCO3 which is the same ratio as...........
1.736ml in 1 litre of water to reduce alkalinity by that rate.
That means 1ml will reduce alkalinity by 508/1.736 = 292mg/l CaCO3. I found 1ml of that acid reduced alkalinity by 445mg/l which is close to the calculated value for sulphuric acid of the density recorded in the picture.

[Eric]

Hi Eric

Should have mentioned before. Mg is 25, sulphate 39, chloride 48.

How do you work out how much alk you have from calcium and magnesium figures?

You can't, well if you make assumptions you can get close.
If all of your 120ppm calcium formed alkalinity, that would be 300mg/l CaCO3.
If all that 25ppm magnesium similarly formed alkalinity that could be another another 160mg/l CaCO3, so the maximum practical amount of alkalinity would be 460mg/l CaCO3. Of course some of the calcium and magnesium would be associated with other anions, so the maximum is theoretical. All in all those figures do balance, your alkalinity would indeed appear to be greater than 300mg/l CaCO3. In some parts of the world their water is less easily predicted, for example, the author of Bru'n Water has said his water supply has a high proportion of its alkalinity associated with sodium, maybe in efforts to reduce limescale in domestic equipment.

I think I can taste it the CRS. There's definitely a taste there that I hadn't come across before.

Wow, those values (Murphy's link) are higher than I'm getting, and higher than I remember seeing anywhere else. Food for thought.

I've ordered some sulphuric and some AMS today so plenty of things to play with.

Cheers

I'm not suggesting Murphy's figures are best, just to make you aware there is not one way to make beer. The final decision is yours.

[Morrisoff too]

Just done my first brew with phosphoric. It got the alkalinity down OK. Mash pH was spot on with the mineral additions from bru'nwater. Not much more scale than usual on the element, came off OK with Saniclean. Bubbling away nicely in the brew fridge. Will update when I've had a taster.