STW area

(That's water to the rest of us!) Beer is about 95% water, so if you want to discuss water treatment, filtering etc this is the place to do it!
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blink

STW area

Post by blink » Sun Jul 13, 2008 11:42 pm

A short while ago just after joining this forum there ws a thread i can't find ref getting hold of a sensible water analysis. So i'll post a short response here now i have spoken to a friend who works at stw and used to supply me with reports.
You need to ask for a schedule 4 analysis. This should give you hardness, alkalinity, salts etc. STW need to do this analysis annually so your report could be nearly 2 yrs out of date if you catch it wrong. However, most water sources are reasonably steady - overall. Bear in mind though that there are seasonal differences as boreholes etc are brought into use.
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stevezx7r

Post by stevezx7r » Mon Jul 14, 2008 10:42 pm

Ta for the heads up.
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MARMITE

Post by MARMITE » Tue Jul 15, 2008 1:51 pm

The schedule 4 report gives sulphates chloride and sodium.It doesnt give calcium magnesium potassium or alkalinity.If you write to customer services at Finham (Coventry) they will supply you with values for calcium and magnesium (both expressed as CaSo4) They dont gather values for potassium at least not for my zone so you will have to guess that (about 4 ) From this info you can calculate your alkalinityAn expert on the forum has shown me how to do this.If you get the figures and PM me I'll do the calcs.
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Post by Andy » Tue Jul 15, 2008 1:59 pm

Also, DaaB has kits available which allow you to measure the alkalinity of your water. Under a fiver posted and easy to use.
Dan!
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Post by Andy » Tue Jul 15, 2008 2:33 pm

DaaB wrote:(Thanks to Del and Mr X, the price was £2.25, sadly that may go up by 10p or so for the next kits I send out depending on whether I can find another deal on jiffy bags).
What a ripoff! :lol:
Dan!
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MARMITE

Post by MARMITE » Tue Jul 15, 2008 8:05 pm

It isn't just the alkalinity to be calculated - the calcium and magnesium figures supplied by Severn Trent will be shown as CaSo4 and these need to be converted to values for ion in their own right. When you have done that you can produce an alkalinity figure which can then be usefully compared using DaaBs test kit. This should also throw up any variations in the water supply.
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Post by Aleman » Tue Jul 15, 2008 8:27 pm

MARMITE wrote:It isn't just the alkalinity to be calculated - the calcium and magnesium figures supplied by Severn Trent will be shown as CaSo4
No, on a standard report they list Calcium as an ion, as they do for Magnesium, Sodium, Zinc, Lead . . .just to name a few. If you are lucky they will quote a 'Hardness' figure (As Caclium Carbonate) and possibly an alkalinity figure (Again as Calcium Carbonate) . . .It may be possible using these two to derive the contribution to the hardness of Magnesium . . . but its not important.

Daab's test kit measures the alkalinity 'directly' You are measuring the amount of acid that needs to be added to the water to reduce the carbonate to 0 . . . or a predetermined level . . . The carbonate (And hydrogen carbonate) is usually derived from chalk, but it could be derived from sodium hydrogen carbonate (so it is possible to have a low hardness water with High alkalinity . . . just not very likely) I have often wondered how these mineral waters can have such low levels of dissolved minerals and a high bicarbonate level . . .I think I found the solution this week, If the water is treated with Slaked Lime (To eliminate calcium which is the way the German brewers do it) the pH is raised quite high, so they bubble CO2 through it to bring the pH down to just above 7 . . . saturating the water with CO2 which forms Hydrogen Carbonate or bicarbonate . . low hardness high alkalinity . . .
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MARMITE

Post by MARMITE » Tue Jul 15, 2008 8:54 pm

Sorry Aleman Calcium and magnesium may be listed as ion in your neck of the woods but in ST they dont.When I contacted them in May I was told that they do collect data but they dont publish them. Apparently they are not mandatory.The letter I eventually received gave values for calcium and magnesium as CaSo4 Their 2007 schedule 4 report which I have pulled off today is the same. Think I'll move to Blackpool! :)
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Graham

Post by Graham » Tue Jul 15, 2008 9:54 pm

Aleman wrote:I have often wondered how these mineral waters can have such low levels of dissolved minerals and a high bicarbonate level . . .I think I found the solution this week, If the water is treated with Slaked Lime (To eliminate calcium which is the way the German brewers do it) the pH is raised quite high, so they bubble CO2 through it to bring the pH down to just above 7 . . . saturating the water with CO2 which forms Hydrogen Carbonate or bicarbonate . . low hardness high alkalinity . . .
What the hell is the bicarbonate bonded to then - Kryptonite?
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MARMITE

Post by MARMITE » Tue Jul 15, 2008 10:35 pm

CORRECTION

My previous post stated that Severn Trent supplied me with figures for Calcium & Magnesium expressed as CaSo4. This was obviously a deliberate mistake on my part caused by not enough beer. Severn Trents figures are expressed as CaCo3. :oops:
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Post by Aleman » Tue Jul 15, 2008 10:52 pm

Graham wrote:What the hell is the bicarbonate bonded to then - Kryptonite?
Yeah, Thats the bit I didn't quite follow either, I need to re read that article . . .Suspect something was left out then? :D
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Graham

Post by Graham » Tue Jul 15, 2008 11:29 pm

I suppose one needs to discover why they were blowing CO2 through their water. The only probably reason, though unlikely, is to lower the pH below the carbonate end-point or equivalence point, which is around pH8.3, such that it is all bicarbonate (all the carbonate moved to bicarbonate), although that doesn't really make sense (to me at least) if they are going to chuck calcium hydroxide into their water.

Are you sure that this is not one of those theories where a little bit of information has been expanded into something impossible? Makes a mockery of the Reinheitsgebot, of course - which always was a bit of a myth anyway.

EDIT
Aw, wish I'd read the original post properly first. Adding slaked lime is going to raise the pH above the carbonate equivalence point and hold carbonate in solution. Blowing CO2 through it afterwards will lower pH again and force more carbonate to precipitate. It does make sense after all. Still not high alkalinity though.
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Post by Aleman » Wed Jul 16, 2008 8:24 am

This is one of those times I wish I still had access to the Flame photometer in the basement of the plant biochem building at Bangor. Looking at the 'stated' mineral content of some of these waters you have things like Ca 6, Mg 2, and bicarbonate 260+ :shock: (I intend to buy a bottle or two tonight for checking) . . . I can recall seeing sodium quoted, which makes me think that a bunch of sodium hydrogen carbonate is used instead . . . . won't be suitable for people on a low sodium diet though . . . . and again we are back at using a 'typical' analysis :twisted:
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