This is one aspect where the KISS principle applies so much. As I said in my lecture, unless you are looking to take a beer from 45/50 up to 48/50 going into water treatment in all it's complexities is really pointless, and relying on published 'perfect' water/beer profiles, be that on the internet, in books, or in a calculator, is a waste of time, given that the vast majority of them are based on Kohlbachs work, and are sourced from the US, I have concerns over some of the pronouncements made, as long as you ignore the warnings that come out as a result of your additions, then you should be in the ball park. Get the alkalinity correct for the style of beer you are brewing and in 90% of cases you will, all other brewing constraints being equal, produce great, potentially award winning, beer. If you consider that 60-70% of flavour compounds come from the yeast, of the remaining 30-40% the vast majority of flavour comes from the malt, meaning that our water treatment will have an effect of 1-5% at most
on the beer flavour. . . . Now where would you think it makes more sense to apply our efforts to produce great beer???
Fundamentally you are correct. No spot test (or even an average result) is going to be an accurate reflection of what the water you receive out of the tap at any given day. For this reason it make the water calculators very much a hit and miss affair, as they cannot represent what is in the water, as you don't know what there was to start with.
It was for this reason that I came up with the simple treatment.
1) Measure and adjust alkalinity with acid / potassium bicarbonate / kalkwasser as required . . I know how much this is going to add / remove from what is there
2) adjust calcium, if required - in my case it always is, use flavour salts as appropriate to the style I'm brewing and the flavours I want to pull out . . . I know how much calcium, sulphate, and chloride I'm adding. . . If I was brewing ion a Hard (*)
water area then I would adjust the flavour ions using a blend of hydrochloric and sulphuric acids in step one. No Calcium addition is required.
Beer factories use RO water and build their profile, but they want a consistent (bland) product as the end result, so they need this level of control. as home brewers we should perhaps be looking to use our water to retain that unique regional flavour
that beers from that region would / do have.
I've gone down the extreme route that Mark has suggested, and that involves taking a sample every month (or so) and getting it analysed by Neil. So far I haven't seen a hugely wild swing in the results, but then it is varying by 30% min to max, I consider than to be a significant swing, but then is an additional 10/20 mg/l calcium / chloride / sulphate actually going to make a massive difference . . . probably not. I am hoping that with this cryptosporidium contamination, will mean that they change to the borehole source they used a couple of years ago, which had an alkalinity of 135mg/l instead of the usual 25-35. That will have a significant impact
Your variation of 50 mg/l in alkalinity will not be accompanied by such a wide variation in the other ions (calcium and magnesium primarily), and as you are measuring and treating you alkalinity you will not need to worry about the other ions that much anyway.
So for me I have gone through the complex build a 'perfect' profile, and yes it works, but its over complex and requires a decent recent water profile. here in the UK we don't have that option easily (I suspect they do not in the US either) Without that you are groping blind and adding and praying. It is much simpler now to measure alkalinity, measure calcium, and measure TDS (Total Dissolved Solids). That would give me more than enough information to hazard an appropriate guess as to the water composition (Especially with my monthly analysis), to tailor it accurately . . .
I still just reduce alkalinity to X with acid (s) . . . What does that do to the flavour ions> . . . add 50-75mg of calcium using appropriate salts to put the sulphate / chloride ratio where I
want it . . . certainly in regard to added sulphate / chloride . . yes I have a good idea where the total levels are, but 15/20/30 mg/l isn't really going to make a huge amount of difference.(*) I'm using hard water in it's correct usage here , as the concentration of calcium and magnesium ions in the water, hard water = lots of calcium = good for brewing