London tapwater

[Aleman]

I think the pilsner water profile on the Brewersfriend website (7 mg/L calcium) must be wrong.

No, the published profile is right, it's just that, like here, the brewers do not necessarily brew with the water drawn from the same place as the published profile

[Charles1968]

It's listed under water targets as "Pilsen (light lager)", which implies you should aim to match it to make pilsner. A bit misleading if it's unsuitable for brewing light lager due to the low calcium.

I've noticed that ion levels recommended for various beer styles vary a great deal from one website to the next. Are any sources more reliable than others?

[AnthonyUK]

That is the issue with matching geographical water profiles as Aleman said. You just don't know what the brewery did additionally which is why I use a style based water profile.

[Charles1968]

Thanks. Where's the best place to find tried and tested style-based profiles, rather than geographical ones?

[AnthonyUK]

I aim to get my water to the right levels for good mash pH, enough calcium and then adjust the sulphate chloride ratio to match the style.
There are loads of profiles in BruNwater, some more USA centric than others but should give you a starting point.

[Eric]

Thanks. Where's the best place to find tried and tested style-based profiles, rather than geographical ones?

I'll venture to suggest the best tried and tested profiles might be those designed for or by those with similar tastes to yourself, as the liquor as well as creating the essential minerals required for brewing, has a not insignificant influence on final flavour.
If you want a light beer, one that depends on hops that goes down well to quench a thirst straight from the fridge on a hot day then go Martin's way with a sulphate bias and low mineral content. To emphasise that style use a yeast like US05 or even WLP008.
On the other hand, if you want something with more flesh on its bones, use a higher mineral content including more than 100ppm chloride with a yeast more at home in such worts to produce extra flavours. Here, from a company that brewed over a century ago then since has sold knowledge and products to brewers, are a list of profiles of which only one has chloride less than 150ppm.
Both will make beer, different beers. Try both.

[Charles1968]

Thanks. Am I right in thinking it's really just a matter of taste, apart from controlling mash pH and keeping enough calcium to prevent problems?

Thames Water replied to my e-mail querying calcium and magnesium as follows:

What is the Calcium and Magnesium level for my area?
You can work out the calcium level for your area by dividing the total hardness by 100, then times it by 40. We don't routinely analyse for magnesium. But, we'd expect the level to be between 25-50mg/l.

If magnesium is that high, won't their formula for guesstimating calcium give the wrong number?

[WallyBrew]

Thanks. Am I right in thinking it's really just a matter of taste, apart from controlling mash pH and keeping enough calcium to prevent problems?

Thames Water replied to my e-mail querying calcium and magnesium as follows:

What is the Calcium and Magnesium level for my area?
You can work out the calcium level for your area by dividing the total hardness by 100, then times it by 40. We don't routinely analyse for magnesium. But, we'd expect the level to be between 25-50mg/l.

If magnesium is that high, won't their formula for guesstimating calcium give the wrong number?

There is no way that the magnesium content of your water is that high. Water within the old ILEA area of London, and I'd venture that Dulwich comes under that, has been fairly constant in composition for years and the magnesium is about 4 to 5. Expressed as calcium carbonate this would be 15 to 21. You need to get past the office junior and onto someone who knows what they are talking about but I suspect that UKAS accreditation bars such people from communication with lesser mortals.

[Charles1968]

There is no way that the magnesium content of your water is that high. Water within the old ILEA area of London, and I'd venture that Dulwich comes under that, has been fairly constant in composition for years and the magnesium is about 4 to 5.

I've come across that before but only on internet forums, so I don't quite know what to make of it. I guess I might have to fork out for a full water analysis.

You need to get past the office junior and onto someone who knows what they are talking about but I suspect that UKAS accreditation bars such people from communication with lesser mortals.

That was my gut feeling. Unless they were right..

[BenB]

Certainly up in North London it's low. My calcium level is 107.5 and from the total hardness figures stated on the water report (quite little variation in hardness it appears) I was able to use an online calculator to confirm the magnesium is in single figures. It seemed to suggest 5 but the ion balance worked better if it was nearer 10. Not a lot though. Might get myself a proper Murphys report done for the hell of it. Be interesting to see what they get. I looked at getting a Salifert Magnesium test kit but they're really designed to be testing levels in the hundreds and thousands not single figures!