Water treatment

I've seen this question raised a few times, but can't find the answer.

I understand the need to treat all the water (mash and sparge) to get the alkalinity down, so I use the total liquor volume to calculate the amount of acid needed.

But to calculate the amount of gypsum and calcium chloride to add, should I use the total liquor volume, or the volume of liquor post boil?

I lose quite a lot of volume during the boil. To keep the maths simple, say I start boiling 30 litres and end up with 20 litres after 90 minutes. Presumably, if my desired wort should have say, 100ppm chloride, then if my liquor has 66ppm, it will be up to 100ppm after boiling a third off it?

Any thoughts?

Thanks, Anthony

I treat the full volume.

It really depends on what you're using your water additions for. If you're using them to change up the pH of the mash by adding CaCl2 or gypsum, then you'll want to treat the whole batch of water like total volume. Since you haven't boiled off anything, its that calculation that will get your pH right. However, if you're using them for post-mash concerns (ie Ca for yeast growth, Cl and SO4 for flavor components) then you could take into account the boil off. Now more than likely, unless your starting water is really high on some of those already, you probably aren't going to hit a bad range after boiling, so worrying about it isn't necessary. If you're in a situation where you happen to have really high sulfate, chloride, or sodium levels to begin with, you may want to take that into account before calculating your salts so you don't wind up too high in the final product.

Thanks, that's helpful. I've been detecting a sulphate flavour, and when I took evaporation into account, I realised that my levels were too high. I'm now using other methods of lowering Ph.

Anthony

A 33% boil off is fairly extreme. If this is actually occurring, then it would be wise to reduce the heating or partially cover the kettle. For a 90 min boil, the boil off should be less than 20%, preferrably around 15%. Yes, the evaporating water does leave the ions behind and that does concentrate them.

The water for mashing and sparging can have differing needs. Sparging water always needs to have low alkalinity. The mashing water may or may not need low alkalinity. More acidic grists may need some alkalinity to help avoid an excessive mash pH drop.

However beside the differing alkalinity goals, I find that treating all the water to produce similar concentrations of Ca, Mg, Na, SO4, and Cl is wise. Its only HCO3 that needs to be tailored to the mash requirements.

From the OP's language usage, I'm guessing he is from the UK or Aussie. A significant problem I see in UK brewing practice is the use of blended acid products (CRS, AMS). These blended acids (hydrochloric and sulfuric) add a fixed ratio of SO4 and Cl. High SO4 is OK in some beers, but allowing Cl to also rise with these high SO4 concentrations is a recipe for minerally beer flavor and harshness. Those products can quickly cause the brewer to overdose their liquor with excessive SO4 and/or Cl. Switching to a more neutral acid like phosphoric could help avoid this problem. Cl should always be below 150 ppm and preferrably less than 100 ppm. When SO4 exceeds 100 ppm, the Cl should be further reduced to the 50 ppm range.

Thanks Martin, yes I'm from the UK. A Scot actually. Thanks for the advice. My New Year's resolution was to tackle water treatment this year! I'm learning a lot. There seems to be a transatlantic divide on the definition of how much Sulphate and Chloride is acceptable. I'm keen to get my levels much lower than I have been. I have a third water tap at my sink which filters the very hard tap water, and removes much of the temporary hardness. An Alkalinity test shows it can reduce it from 300ppm down to 20 or so. It's a filter, not a water softener, so it's not adding any sodium. I assume it is not affecting my Sulphate (17ppm) and Chloride (28 ppm) levels though. To get my calcium back up, I'm using Gypsum and Calcium Chloride additions, hence my original question.

I agree that minimising the use of CRS is a good idea. It raises the Sulphate and Chloride levels without increasing the Calcium, I believe?

Well, if that third tap is producing water with only 20 ppm alkalinity, then an acid may not be necessary. I'm wondering if that system is one of those citric acid units? They reduce alkalinity and chelate calcium, which effectively prevents it from scaling.

Using the gypsum and/or calcium chloride is a good alternative that adds calcium. You are correct CRS does not add calcium, as its a blend of HCl and H2SO4. I'm not sure where the recommendation to sharply increase the Cl and SO4 levels in UK brewing water came from. In many locations around the island, there is already plenty of sulfate and/or chloride along with a healthy alkalinity. Recommending brewers to use CRS type acid blends to reduce alkalinity doesn't appear wise in some cases. Unfortunately, the brewing advice is to use that acid instead of a more appropriate Lactic or Phosphoric acid. Oh well!

Martin,

I asked the filter supplier how it worked. He said:

"The HM600 operates by ion exchange, the exchange ion is Hydrogen so no harmless effects but the pH will drop in the early life of the cartridge in areas for high temporary hardness."

I'd welcome your opinion on whether this is a suitable start for my water treatment. I plan to mix this with my tap water, like you would with distilled water, to create the
right level of alkalinity.

Thanks, Anthony