Phosphoric acid - supply

[Eric]

Please can we avoid all BJCP references?

OK, your system is similar to my main gear, 70L HLT and boiler with 40L MT, with 50, 70 and 100l FVs.

Just a little difficulty confirming your water's ion balance with that large amount of nitrate, presume it is from farm fertiliser and me not knowing what is actually spread, but that's possibly irrelevant and can be ignored. It's good brewing water for beers of the types you mention, although Landlord starts with softer water than yours.

5% dark crystal has a significant influence pH as might the amber at over 6% depending upon how the malt was kilned. It is one of those that needs approaching with degree of caution. That said I would target mash alkalinity to be 30 to 35ppm as CaCO3, mash in with my own water which has usually over 80ppm calcium and have to hand enough calcium salts in 5g units to provide 200ppm calcium over all liquor if that makes sense. My last bitter had alkalinity at 28ppm with calcium 150ppm.

I'm no fan of Bru'nWater, Martin himself knows that, but my main problem here is the meaning in your earlier post of "it gave me an alkalinity figure after adding acid of 70,.... ". Not sure if that is a measure of alkalinity or of a volume of a specific acid.

What I do is determine the amount of acid required to reduce alkalinity to the desired level, add slightly less acid and remeasure alkalinity with a Salifert kit, then correct if necessary. I also determine the amount of calcium required for the style and choose the breakdown of salts to give the ratio of chloride to sulphate, weigh them out and break them down into equal numbers of packs in cling film. Those can be added at any stage, selected for best effect. Also, the sparge liquor starts with the same alkalinity of that for the mash, but is reduced as the sparge continues to avoid pH of runnings rising above 5.6. It sounds complex, but I can measure alkalinity and all major ions with a single TDS reading and can use individual acids of choice, using a dedicated spreadsheet, and all falls in place on the day.

Abbot and London Pride should be 2:1 sulphate:chloride, while Landlord is chloride forward. You also won't likely replicate Landlord without the Ragus invert and a decent hopback.

[MashBag]

Thanks Eric. Superb answer.
I am still an absolute novice with water treatment and your patience is really appreciated.

[JonA]

Thanks a lot Eric, water treatment is complex and my knowledge of it is very superficial. I will try that procedure on my next brew.

Measuring all ions from total dissolved solids sounds pretty cool - how is that done? A brewing friend of mine bought a TDS meter, but he never worked out how to turn the reading into useful data.

[Eric]

A Salifert KH test kit allows you to measure alkalinity in your supply water with more than sufficient accuracy for brewing.

AMS/CRS will neutralise alkalinity as CaCO3 at a rate of 183 mg /ml, half by hydrochloric and half by sulphuric acid. Thus to reduce alkalinity by 100 mg/l would require 0.5405ml of CRS which would also increase sulphate by 48 mg/l and chloride by 35.4 mg/l.

Using phosphoric acid is a little more difficult to determine because of the potential for calcium phosphate so formed to deposit, although alkalinity associated with magnesium probably will not as magnesium salts are more soluble that those of calcium. No major ion is lost in that way with CRS or either of the acids used in its production.

After treating the water, a further Salifert test will confirm the result of such treatment after CO2 is dissipated to atmosphere.

Calcium sulphate and calcium chloride can be used to add the ions they contain. Gypsum is 23.24% calcium and 55.79% sulphate while calcium chloride flake (dihydrate) should be 27.26% calcium and 48.09% chloride. Other salts exist but are not an essential ingredient currently
A TDS meter is but a conductivity meter, an AC potential difference between 2 electrodes and the current passed is measured and displayed in digital form. They are most frequently calibrated for saline solutions, but some, mine for certain, can be manually recalibrated in a known source.

A series of analyses of my supply water across a period when it fluctuated significantly were completed and reported by WallyBrew. Samples of the tested water were held and used to recalibrate a TDS meter to match the sum of the major ions measured by analysis. Plots were charted of each major ion levels against TDS and a polynomial derived to fit that plot and origin of the graph.

SO4TDS.jpg (91.95 KiB) Viewed 3252 times

With acids and salts of known and predictable influences together with formulae for ion content from TDS measurement, it was possible to create a spreadsheet specific to my own supply water that from a single TDS meter reading will produce the ingredients and quantities to produce a desired profile from that day's water.

[JonA]

Very cool, a bit advanced for me at this stage

Could you have modified your water manually to obtain your reference samples rather than using natural variations in it's composition - just wondering, as it might be difficult to replicate the procedure for anyone else who wanted to try it, if they were relying on natural variations of their water.

[JonA]

... do you know if WallyBrew is still doing water analysis for forum members? It would be good to get accurate numbers, rather than my company water report which is just readings from the previous year that have been averaged.

[JonA]

I thought I'd post the (very simplistic) picture which I use to try and understand the basic interactions between pH and alkalinity in the mash - give everyone a laugh on a Sunday

I appreciate that there are going to be numerous other processes involved, but for someone like me who just scraped through their chemistry O-level ...

When the grains and liquor mix, the acidity of the grains tries to pull the pH down from it's starting point, which is probably around seven-ish.

The alkalinity in the liquor is acting like a spring - resisting this downward pull and trying to maintain the starting pH of the liquor. When mixing is complete, these forces kind of "balance" and the pH (hopefully) ends up within the desired range at around five point something.

If the alkalinity is too high and the grains are not very acidic, the spring is too strong and the pH doesn't drop enough - result is the pH ends up above the desired range.

If there are a lot of acidic malts in the mash - roast and crystal etc. and the alkalinity is too low, the spring is too weak and the pH lowering force is strong - result is the pH ends up below the desired range.

So the grain acidity vs. liquor alkalinity is always a balancing act between the two acting on the mash pH.

[Eric]

Very cool, a bit advanced for me at this stage

Could you have modified your water manually to obtain your reference samples rather than using natural variations in it's composition - just wondering, as it might be difficult to replicate the procedure for anyone else who wanted to try it, if they were relying on natural variations of their water.

Just to eliminate a potential misunderstanding, I adjust mineral content of my water supply to that desired for the upcoming brew. I therefore first need to ascertain the supplies mineral content before preparing brewing liquor. Weather influences mineral levels in reservoirs and aquifers used by water companies as prolonged rainfall will dilute mineral levels and hot dry periods concentrate them.

[Eric]

Can we remove any, even the remotest, idea that pH of brewing liquor has influence on mash pH.

pH of water will be significantly influenced by dissolved CO2. Now pH 4.4, or thereabouts, is generally accepted as the end point for alkalinity, thus water of a pH lower than your mash target can still contain alkalinity.

The spring analogy for alkalinity does have some validity, so in UK and elsewhere alkalinity will be precisely set before mashing in, a bit like choosing the rope length and elasticity before beginning a bungee jump.

Mashing pale malt with deionised water would likely measure pH 6.0 after an hour, so even without alkalinity we don't get a suitable mash pH. Adding some crystal or more kilned malt would lower pH as would adding some calcium. Would you consider adding more calcium to your brewing liquor?

[JonA]

... Would you consider adding more calcium to your brewing liquor?

Yes I certainly would, but when it comes to adding it via gypsum or calcium chloride, that's when things get a bit complicated for me.

[guypettigrew]

Can we remove any, even the remotest, idea that pH of brewing liquor has influence on mash pH.

Yes please!! A fun experiment is to run some water from the tap and measure the pH. Then come back 15 minutes later and do it again, then another 15 minutes etc etc.

The pH changes every time, as the water is exposed to the air.

It's ages since I did this, so can't remember which way the pH goes. I think it drops, but not sure.

Guy

[Eric]

... Would you consider adding more calcium to your brewing liquor?

Yes I certainly would, but when it comes to adding it via gypsum or calcium chloride, that's when things get a bit complicated for me.

Some basic mathematics are required, a far better understanding can be got by doing a few sums. The following is what I wrote a little above a picture of the plot of sulphate against TDS.

Calcium sulphate and calcium chloride can be used to add the ions they contain. Gypsum is 23.24% calcium and 55.79% sulphate while calcium chloride flake (dihydrate) should be 27.26% calcium and 48.09% chloride. Other salts exist but are not an essential ingredient currently

You can't just add calcium or sulphate or chloride or any individual ion.

In very rough terms, a quarter of gypsum's weight or calcium chloride flake's weight is calcium, just over a half of gypsum is sulphate and marginally under half of calcium chloride flake is chloride.

Thus adding 4g of gypsum will add just under 1g of calcium and a bit over 2g of sulphate, more accurately 930mg calcium and 2232mg sulphate. Put into 30 litres of water will increase the calcium content by 31mg/l or ppm and sulphate by 74mg/l, otherwise ppm.

4g of calcium chloride flake in 30 litres of water will likewise increase calcium by 36ppm and chloride by 64ppm.

Initially there is little point for extra brewing salts, leave those until you have full grasp of the concept.

Calcium chloride flake is hygroscopic, meaning it sucks up every bit of moisture it comes across. Bear this in mind and keep them well sealed when not in use.

Does that help?

[JonA]

Yes it does, thanks very much.