Another Salifert question

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Another Salifert question

Post by guypettigrew » Sun Jan 28, 2018 3:26 pm

This isn't really about beer, but it is about the Salifert test kit--hope that's OK.

About a year ago we had a water softener fitted. A test done by Murphys a couple of weeks later showed total hardness (as CaCO3) at 3.00ppm. And 222ppm for the hard water bypass. Seemed very reasonable.

We were worried the softener might not be working, so I tested the softened water yesterday. Came out at about 200ppm, same as the hard water.

Went to a friends today. He has a softener. Tested at 250ppm.

It seems clear to me that I have absolutely no idea what the Salifert kit is testing!!! I thought it tested hardness as CaCO3.

I'd be really grateful if someone could enlighten me. Especially as I've asked the water softener bloke to come round as it looked like the thing wasn't working!

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Re: Another Salifert question

Post by WallyBrew » Sun Jan 28, 2018 6:38 pm

It measures the alkalinity the HCO3 bit. Nothing to do with calcium. The softener just exchanges the Ca for 2Na and leaves the alkalinity as is. Soft water is not a good choice for brewing.

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Re: Another Salifert question

Post by guypettigrew » Sun Jan 28, 2018 6:57 pm

WallyBrew wrote:
Sun Jan 28, 2018 6:38 pm
It measures the alkalinity the HCO3 bit. Nothing to do with calcium. The softener just exchanges the Ca for 2Na and leaves the alkalinity as is. Soft water is not a good choice for brewing.
Thanks--but still confused! The water from the softener doesn't taste salty and we don't have a hard water tap in the house anywhere. Apparently the regs have changed and you don't need one now as the amount of salt in softened water is negligible.

And why is the Salifert kit labelled 'carbonate hardness'? Isn't it measuring anything to do with hardness?

Agree with you about not using softened water for brewing. Tried it once--absolutely horrid beer was the result. Weird vegetable taste and smell. never to be repeated. Treated hard water is hugely better, especially since the analysis you did for me, thanks!

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Re: Another Salifert question

Post by MTW » Sun Jan 28, 2018 7:30 pm

Hopefully someone can elaborate, but this much I know: 'hardness' refers to the level of calcium and magnesium ions in the water; 'alkalinity' refers to the level of bicarbonate and carbonate ions in the water. That's in a page by Aleman elsewhere, that I keep bookmarked!

And from Wiki, regarding your second question, though perhaps not quite answering it:
"...for water with a pH below 8.5...carbonate alkalinity will equal carbonate hardness to within an error of less than 1%."
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Re: Another Salifert question

Post by Kev888 » Sun Jan 28, 2018 7:39 pm

The salifert KH kit measures the total alkalinity, not the hardness of the water. The water softener isn't designed to change the alkalinity, so testing for that doesn't really say much about the softener's effectiveness.

Alkalinity is also referred to as carbonate hardness (perhaps more so in the aquarium world), hence it being on the kit. It may be almost the same, but in brewing it is a confusing term to my mind; carbonate-hardness is not water hardness. People get confused enough between alkalinity and hardness already, because they can be expressed in similar units.

BTW, salifert do make a calcium testing kit, I use one to make sure I've enough in my brewing liquor. Though I don't know how much calcium difference one would expect from your softener.
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Re: Another Salifert question

Post by guypettigrew » Sun Jan 28, 2018 10:06 pm

MTW wrote:
Sun Jan 28, 2018 7:30 pm
And from Wiki, regarding your second question, though perhaps not quite answering it:
"...for water with a pH below 8.5...carbonate alkalinity will equal carbonate hardness to within an error of less than 1%."
Blimey, this is getting ever more confusing!

Kev888's reply suggests the Salifert kit doesn't measure hardness.

The Wiki quote above suggests it does.

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Re: Another Salifert question

Post by Kev888 » Sun Jan 28, 2018 11:01 pm

The salifert kit doesn't measure water hardness (to use the familiar term); it measures alkalinity, sometimes referred to interchangeably as carbonate hardness. There isn't doubt about this, it even says so on the pack.

Similarly, the wiki MTW quoted doesn't suggest that the kit measures water hardness. It just supports that carbonate hardness and alkalinity are (for most purposes) equivalent.

If you can accept that Alkalinity (or carbonate hardness) is not the same thing as water hardness, then you may find it all slots into place. And then forget the pack mentions the term carbonate hardness and just call it alkalinity, to avoid future confusion!
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Re: Another Salifert question

Post by guypettigrew » Sun Jan 28, 2018 11:25 pm

OK. Brain reorganisation in progress!

But-what is water hardness if it's not carbonate hardness?

And why do Murphys and water companies quote hardness as CaCO3?

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Re: Another Salifert question

Post by Kev888 » Sun Jan 28, 2018 11:59 pm

Water hardness is an old term (IIRC something to do with its effect on soap) but more or less describes the amount of calcium and magnesium ions in the water. If you have hard water you'll likely see much more scale as these precipitate. I understand that softeners convert the calcium to avoid that, though I don't use one myself; the calcium is generally wanted in brewing liquor.

Alkalinity indicates the bicarbonate and carbonate ions in the water. In terms of brewing, it relates to the buffering power and helps predict the pH of the mash, so is particularly important. For lighter beers made from more lightly kilned malts alkalinity often needs reducing, but this does not mean losing the calcium, which (as mentioned) is a different thing.

Alkalinity can be 'expressed as' its equivalent in calcium carbonate, and supposedly this can make various comparisons and calculations easier so it has become a conventional method in some fields. But this does not mean it actually 'is' CaCO3, it is not. In home-brewing the main result of using the same units seems to be to cause confusion between the two.

EDIT: I should say that I'm no expert myself, this is just what I've gained from forum members over the years, wallybrew, aleman and eric in particular. I'm sure they will correct me if I've made any inadvertent gaffs.
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Re: Another Salifert question

Post by Aleman » Mon Jan 29, 2018 12:33 am

Hardness is indeed a confusing term, and should be avoided in brewing IMO.

Hardness is a measure of the amount of calcium and magnesium ions in the water, generally, but not always, these are combined with 'carbonate' ions (generally carbonate ion species depending on pH). In the good old days 'Hardness' (Calcium and magnesium levels) were determined using a 'standard' soap solution, and shaking the sh!t out of it, the amount of foam produced was directly comparable to the amount of calcium and magnesium. Just for fun, water companies that decided to equate this back as if the hardness was completely provided by calcium carbonate 'As CaCO3'.

Alkalinity is a measure of the 'carbonate' species present in the water, due to historical reasons the water companies report this as if all the carbonate ions were produced from calcium carbonate 'As CaCO3'

Confusing? To Frickin' Right it's confusing!

As for what salifert put on their packaging 'Carbonate Hardness' in the aquarium world is also known as 'total alkalinity' generally because one term is used in Germany, and one in the UK, and even one in the US. ... That doesn't muddy the water at all :roll:

It's much easier to use the terms alkalinity, when referring to 'carbonate species', which we generally don't want in brewing liquor, and calcium and magnesium instead of hardness, which we do want in brewing liquor. ... unless you are American :whistle:

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Re: Another Salifert question

Post by orlando » Mon Jan 29, 2018 8:14 am

For those of you who wish to understand the science-good luck. For those who just want to know what to do, keep the alkalinity of your mash to come out between 5.2 - 5.6. Pales < 30 Mild 50, Porters 100, Stout 150. Get your Calcium levels at 100 minimum preferably 150+ and you will be more than happy with the results. With experience of brewing to those numbers you will learn to adjust depending upon your recipe and system/process. The numbers are not written in stone and disaster does not befall you if you are 1 ppm out. Sulphate & Chloride ratios are more important than the numbers themselves, extremes being the exception. But, and this is the big but, you have to KNOW what you are starting with. Get a water report from someone who analyses the water from a brewing perspective.

There are choices in what you use to reduce alkalinity (most of us have to, feel sorry for those who have to raise it as this is not trivial) and those choices will influence the sulphate/chloride/calcium levels. But that is for another day.
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Re: Another Salifert question

Post by guypettigrew » Mon Jan 29, 2018 10:22 am

Thanks everyone--really grateful for all the input. So, the Salifert 'hardness' kit doesn't test hardness. Fine, got that now! I'll assume the water softener is doing its job.

As to beer making---no problem. I use hard water which has been tested by Wallybrew, and Eric has provided loads of useful advice. I'm now able to reduce the alkalinity to whatever I want, up the calcium to about 150 and manipulate the sulphate:chloride ratio. Since learning how to do this, the quality of my beer has significantly increased.

Thanks again.

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Re: Another Salifert question

Post by orlando » Mon Jan 29, 2018 10:49 am

guypettigrew wrote:
Mon Jan 29, 2018 10:22 am
Thanks everyone--really grateful for all the input. So, the Salifert 'hardness' kit doesn't test hardness. Fine, got that now! I'll assume the water softener is doing its job.

As to beer making---no problem. I use hard water which has been tested by Wallybrew, and Eric has provided loads of useful advice. I'm now able to reduce the alkalinity to whatever I want, up the calcium to about 150 and manipulate the sulphate:chloride ratio. Since learning how to do this, the quality of my beer has significantly increased.
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Re: Another Salifert question

Post by Kev888 » Mon Jan 29, 2018 11:07 am

Good stuff! Though just to avoid misunderstanding of skim-readers: the kit is named 'carbonate hardness' / alkalinity (KH/Alk) which are alternative names for the same thing, and different to water hardness. Calling it the Alkalinity kit will help avoid confusion over what is hard :)
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Re: Another Salifert question

Post by Carnot » Mon Feb 12, 2018 7:27 am

I can understand the confusion that some people are having with hardness determinations and alkalinity. The term hardness came about from soap manufacturers and the use of steam in industry. Hardness is normally defined in terms of temporary and permanent hardness, which is usually assumed to be due to calcium and magnesium salts. In simple terms most hardness in potable water is due to carbonates, usually existing as bicarbonate. Bicarbonates do not affect water taste, whereas sulphates and chlorides can be very noticeable as the concentration increases. Temporary hardness is due to bicarbonates which decompose when heated(boiled) to form the carbonate and carbon dioxide. Calcium and magnesium carbonates are only sparingly soluble and will precipitate. This is what forms as scale in a kettle. Calcium and Magnesium sulphates and chlorides are much more soluble, and can be assumed to not precipitate if the water is boiled, though if concentrated the solubility limit could be exceeded.

The early soaps were made by reacting caustic soda with a suitable organic acid, usually stearic acid, to form sodium stearate which acts as a surfactant (surface active substance). However calcium and magnesium salts will exchange with sodium to from the calcium and magnesium stearates which precipitate as a scum. This requires more soap to be required, in order to create a free amount of sodium stearate in solution.

In water determinations alklanitity is measured as a proxy for bicarbonate. There is no simple test fro bicarbonate and many water co's do not even bother. Total hardness and calcium hardness can be determined by titration with EDTA. Thus by measuring the alklainity, total hardness and calcium hardness it is possible to get a good idea of the water composition with respect to brewing. Chloride ion is easy to determine, sulphate less easy.

Normally Total Hardness - Alklalinity = Permanent Hardness assuming that you have all your units correct, which is why it is often reported as mg/L(ppm) CaCO3, but can also be reported in millimoles/ L or mg/L substance (eg Ca).

This is where a lot of the confusion arises. In terms of the Salifert test the alaklinity determination was being used as a proxy for the total permanent hardness- adding to the confusion.

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