Water treatment

[bandit]

You don't add enough acid to reduce the pH - that would be overdoing it

Can you explain this bit please

[Graham]

You don't add enough acid to reduce the pH - that would be overdoing it

Can you explain this bit please

Alkalinity is the capacity of a system to resist changes in pH; resist acidity. The terms "alkali" and "alkalinity" get confused; despite the similarity in names they mean different things.

If you add a very small amount of acid to pure water, the pH will drop like a stone.

If you add a considerably greater quantity of acid to a solution containing carbonate - same thing as alkalinity, the pH won't budge. Well, it might do momentarily, but it will soon restore itself close to the original pH. It restores equilibrium; opposes the change, a condition known as buffering.

You can continue adding acid for some time and the pH will only move very gradually, until you have added enough to use up all the alkalinity, neutralise it, then the pH will drop like a stone. It's a sort of negative feedback.

This buffering effect, alkalinity, gets carried across to the mash, and it resists us moving the mash to the optimum pH, which is why we want to get rid of it. One way of getting rid of it is to use up most of the alkalinity beforehand, by neutralising it with acid.

If you add too much acid, over and above that required to merely neutralise the alkalinity, then you will lower the pH of the water considerably and your mash pH can then be too far out in the opposite direction. That is what I meant by overdoing it.

I've been trying to think of an everyday, real world analogy, but I can't.

Hope that makes sense.

[Aleman]

If you add too mush acid, over and above that required to merely neutralise the alkalinity, then you will lower the pH of the water and your mash pH can then be too far out in the opposite direction.

Graham should have noted however that this is a situation normally experienced by Inuit brewers

[Graham]

If you add too mush acid, over and above that required to merely neutralise the alkalinity, then you will lower the pH of the water and your mash pH can then be too far out in the opposite direction.

Graham should have noted however that this is a situation normally experienced by Inuit brewers

Whoops! Corrected!

[bandit]

So can I presume that by dropping the Ph of the liquor to 6.4 and allowing the grain bill in the mash to naturally buffer the solution and drop itself to 5.2 that I am on a winner. I then add the minerals to the boiler to stylise the brew

[Graham]

So can I presume that by dropping the Ph of the liquor to 6.4 and allowing the grain bill in the mash to naturally buffer the solution and drop itself to 5.2 that I am on a winner. I then add the minerals to the boiler to stylise the brew

No the pH of the water has nothing to do with it. You can have acidic water and still have high alkalinity.

You could probably test a sample of your water if you had an accurate pH meter and some CRS and plot pH against acid added to the water. - keep adding little drops of acid or diluted acid (of known dilution) and measure the pH and plot it on a graph. The point at which the slope of the graph changes suddenly (or just before it) and the pH plummets rather than drops gradually is the point at which the alkalinity is used up. You could then work out how much CRS is needed to neutralise the alkalinity in your water, although you couldn't get a figure for actual alkalinity without some serious maths and knowing more about CRS.

However, it is not something that I have done or would recommend.

Alternatively buy an alkalinity test kit and use CRS as instructed.
Or ask your local aquaria shop what the alkalinity is typically.
OR ask a swimming-pool operator what the alkalinity is.
Or ask your water board what the alkalinity is.

Personally I favour boiling, despite the time taken and the energy innefficiency. The advantages of boiling are:

* You can't overdo it - impossible.

* You can't under-do it if you boil long enough.

* You are only removing things from the water not adding anything.

* You are not adding other ions to the water and changing the water balance away from its original.

* It is easier to match to a particular water profile from an analysis because you've not added other stuff like sulphate and chloride to the water which will complicate matters.

* It always works.

[Madbrewer]

I think my understanding of this topic exemplifies my rather meagre O'level grade in Chemistry now .................

For my Hard Water treatment in brewing Ales/ Bitters should I consider adding Epsom Salts to already cooled previously boiled liqor (water).

[Graham]

For my Hard Water treatment in brewing Ales/ Bitters should I consider adding Epsom Salts to already cooled previously boiled liqor (water).

Don't know if you meant Gypsum rather than Epsom salts.

Epsom salts will not affect the mash - magnesium is required by the yeast and the addition of Epsom salts will ensure that it's got plenty. It is only required in small amounts, almost trace: 1 gram in 25 litres is ample. You can add it where you like: water, mash, copper or even to the fermenter.

[WallyBrew]

So can I presume that by dropping the Ph of the liquor to 6.4 and allowing the grain bill in the mash to naturally buffer the solution and drop itself to 5.2 that I am on a winner

Just to add to your confusion:-

If you were to mash pale ale malt with distilled water the mash pH would be about 5.8. Therefore to achieve a pH in the optimum range of 5.1 to 5.4 you will have to add something to the liquor/grist because distilled water has no buffering power.

A 10 % mash of Maris otter pale malt from Warminster gives a value of 5.75 in distilled water and requires 7ml of 0.02M Hydrochloric acid to be added to 100ml of the wort to shift the pH to 5.2.

Doing some strange calculations based on text book material it would appear that if one mashes with distilled water then an addition of 1.8g of gypsum (calcium sulphate dihydrate) per kg of malt will be required to achieve a mash pH of 5.2. There are of course no guarantees that this will work.

However, I recently achieved an initial mash pH of 5.4 after adjusting the mash liquor to pH 6 and adding gypsum at the rate of 5g/3800g of malt (less than calculated for distilled water). Next time I will adjust the liquor pH to 5.8 and add gypsum at the rate of 1.8/kg of malt.

And Graham is completely correct in stating that you can have acid water that has alkalinity it is down to the dissolved carbon dioxide which of course is rapidly removed by warming the water.

[Graham]

And Graham is completely correct in stating that you can have acid water that has alkalinity it is down to the dissolved carbon dioxide which of course is rapidly removed by warming the water.

Perhaps I used the wrong terminology.

Alkali = a chemical, should really be called a "base".
Acid = another chemical.
Alkaline = Something with a pH above pH7
Acidic = Something with a pH below pH7

Alkalinity = none of the above, actually means buffering power.
Acidic solutions, solutions below pH7, can still have buffering power and therefore alkalinity.

The type of alkalinity that we are interested in is bicarbonate and that can exist down to pH5. Water boards when testing for alkalinity usually titrate to below pH4.5 to ensure they are below the bottom limit. The Palintest "M" reagent (methyl orange) changes colour at pH 4.3.

[nobby]

some more info on calculating hardness of your water

http://users.tinyonline.co.uk/chrisshort/waterhard.htm

[Graham]

some more info on calculating hardness of your water

Hardness and alkalinity are not the same thing. Hardness is calcium and magnesium. Alkalinity in our case is carbonate/ bicarbonate.

With chalk, calcium carbonate, CaCo3, the Ca bit is the hardness; the CO3 bit is the alkalinity. One can exist without the other.

Calcium sulphate, for instance, adds hardness but not alkalinity.

[Aleman]

With chalk, calcium carbonate, CaCo3, the Ca bit is the hardness; the CO3 bit is the alkalinity. One can exist without the other.

Calcium sulphate, for instance, adds hardness but not alkalinity.

Of course the confusion comes from the terms temporary 'hardness' and permanent Hardness! Temporary Hardness (From Calcium Carbonate) can be removed by boiling - Causing precipitation of calcium carbonate as its less soluble in hot water, as this removes Calcium it reduces the hardness. Permanent Hardness is from other totally soluble compounds like calcium sulphate which do not precipitate on boiling.

There is much misinformation out there

[bandit]

Ok, so if I add hydrochloric acid, stir to release Co2 and warm the liquor slightly I will see a reduction in pH and then the pH will slowly start to rise again as the carbonates pick up hydrogen ions and become carbonic acid which is neutral. I then add more acid and repeat until I reach a stable pH.

For pale ale, what would be the nominal starting pH to achieve a mash of pH 5.2?

I have a residual calcium content of 60 mg/l which I presume is sufficient for the enzymes to work correctly in the mash. I will add a more balanced calcium profile to the boiler

[Graham]

I wish I had done some sort of chemistry at school, this all seems well explained but there's a whole chunk of info i'm missing before I can even begin to understand water chemistry properly

Luckily i'm happy with my beer cause I could get seriously depressed if I had to do anything other than alter my mash PH

Saying all that though, I think this should be a sticky if everyone is happy with that.

I learned far more about chemistry after I started brewing than I ever did at school - I am still very much an amateur on that front.

Altering mash pH is what is all about, and all anyone should be worried about, if at all, and it can be done empirically.

Sticky: I don't mind, but this is probably getting too far above what is really required and may serve to confuse and discourage rather than educate.