Alkalinity and Salifert kit

[MattGuk]

Hi all, just looking for a bit of advice.
I have just got back into home-brewing after a 5 year break and have decided to look into water chemistry.
I live in Oxford where our water is USUALLY hard.
Over the past 6 weeks I have brewed 2 batches, both time checking my alkalinity with the Salifert KH kit.
First time my water had a reading of 156ppm so adjusted with CRS which I believe was about 21ml total in my mash ( no sparge ). The 2nd brew, the Alkalinity had dropped BIG TIME, to the point I am questioning my math, as the test indicate I had an alkalinity of 70ppm.
Has anybody else had anything like this, or is this just me being stupid and missing something?

Cheers for any help

[Eric]

Hi Matt, welcome to Jim's.

Sounds like your water behaves as does mine. This year has been mostly dry until quite recently and my tapwater has been as hard as it ever gets over the summer. This rain has also significantly reduced alkalinity (and all minerals) in my water supply. I use a cheap TDS meter to roughly determine mineral levels and measure alkalinity with a Salifert kit after treatment in order to achieve consistent results.

[MattGuk]

Hi Eric, thanks for the reply.
I don't have a TDS meter, but I do have a p.h meter and always have always hit around 5.2 - 5.5 p.h since testing and using CRS, just didn't know that Alkalinity could fluctuate that much.
Are there any side effect that anybody knows of when using CRS at high amounts like 20+ml per batch?
I only ask because one of my beers turned out with what I can only describe as I slight acidic bit to it, although I did over carbonate in the bottle a bit and wonder if the bite could be carbonic acid?

[Jocky]

Hi Eric, thanks for the reply.
I don't have a TDS meter, but I do have a p.h meter and always have always hit around 5.2 - 5.5 p.h since testing and using CRS, just didn't know that Alkalinity could fluctuate that much.
Are there any side effect that anybody knows of when using CRS at high amounts like 20+ml per batch?
I only ask because one of my beers turned out with what I can only describe as I slight acidic bit to it, although I did over carbonate in the bottle a bit and wonder if the bite could be carbonic acid?

I have alkalinity of 250ppm and have treated entire batches with CRS, although my sulphate and chloride levels start off low (<20ppm). I think more likely it that it's the over carbonation. You'd only know by pouring a sample and giving it a really good swirl in the glass to knock out carbonation.

[MattGuk]

Ok thanks for that info, it's still a nice beer but just got a little sour kick lol. My chloride and sulphate are fairly low anyway before treatment

[Cobnut]

Water here in Suffolk is also super hard. For my latest batch I tested using the Salifert kit and it needed more than 1ml of the test reagent to change colour giving me a reading of >300ppm. I used approx. 60ml AMS/CRS for a 30L batch. This is a bit more than the more normal c. 50ml I use (hardness had risen since the previous batch). I've never noticed any off flavours as a result of this level of AMS/CRS.

Other members of my LHBC are starting to use RO systems, but I've had no issues with using AMS/CRS so far, so CBA with RO!

[MattGuk]

Good to hear, also would boiling reduce Alkalinity and Rob the calcium away together?
I brew in a brewmonk Magnus all in one and was thinking about boiling my water, but would be a pain to decant it into multiple containers to get rid of any precipitate

[MattGuk]

Also, I'm thinking of trying bottled water as the mineral content look almost perfect, the bit I'm not sure on is, bicarbonate is listed as 150, now does this refer to Alkalinity? If so, would I treat that as Hc03 or CAC03?
Sorry for being dumb, I think me overthinking things is causing me to get a little confused.

[Cobnut]

Boiling will reduce alkalinity, but (and others here know more than I!!) I believe it will also precipitate out Calcium which we want.

Some people in hardwater areas use bottled water (Tesco Ashbeck is a good option, I believe).

There are many ways to skin your cat!

I think HCO3 is what is known as bicarbonate, but I admit I get a little confused about the differences between alkalinity as CACO3 and HCO3 and what the salifert kit is telling me.

Wait here long enough and someone will come up with an answer.

Or an opinion

[MattGuk]

Well I just boiled a small amount of water to test.
Alkalinity before was 98.8 as CAC03, after a vigorous 10 min boil, Alkalinity went down to 28.2.
All I need now is a calcium test kit.

[PeeBee]

… I think HCO3 is what is known as bicarbonate, but I admit I get a little confused about the differences between alkalinity as CACO3 and HCO3 and what the salifert kit is telling me. …

There is virtually no carbonate, or in many cases no carbonate, in UK tap water; it will all be bicarbonate. Difficult to get your head around because "as CaCO3" is such a common means of measuring things, such as "Alkalinity". "As CaCO3" is not the same as "is CaCO3"! Baffling isn't it? It gets worse!

"Alkalinity" is not a tangible "thing". It is a concept. "Alkalinity" and "Hardness" are different concepts yet are often spoke about as referring to the same thing (they don't). "Alkalinity" and "Basicity" (things are acid up to "neutral" pH7, after which they are Bases, or alkaline) must never be confused.

Hopefully I'm summarising it right, the proof being you're probably getting more confused!

We used to make do with "temporary hardness" ("carbonate" hardness, mainly due to Carbonate and Bicarbonate ions) and "permanent hardness" (almost entirely due to Calcium and, to a lesser extent, Magnesium ions) but this was considered simplistic and so we get lumbered with "Alkalinity". Trouble being no-one re-educated folk to think in different concepts and its common to think of "Alkalinity" and "Temporary Hardness" as "things" existing alongside each other. They are not, nor are they the same thing yet both are mainly due to bicarbonate.


Anyway, I'm ranting ('cos this fantasy had mislead me for so long). I'll leave it to someone better informed to finish, else I'll come back later and complete the confusion I started. Meanwhile … chew on this:

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[Eric]

It is standard practice to measure both hardness and alkalinity in terms of calcium carbonate. That does not mean those consist of calcium carbonate or contain any calcium or carbonate, but has equivalent hardness or alkalinity measured as calcium carbonate or replaced by it. Take a deep breath, but you will find this simplifies matters once you grasp the subject.

Alkalinity can be found in many chemical forms, but most in natural water is in the form of calcium bicarbonate. That cannot exist in solid form., only in solution. When you see bicarbonate, do yourself a favour and divide it by 1.22 and call it calcium carbonate. You will find most recognised text on brewing or water do use calcium carbonate.

That was a significant drop in alkalinity from that boil. You can assume the reduction in alkalinty was all calcium related as any alkalinity associated with magnesium remains soluble despite being boiled. The same is true with alkalinity associated with sodium, but there will be none such in your Oxford water, but there might be in some bottled waters.

So, how much calcium did you loose? Very easy if you work in measures of calcium carbonate as its molecular weight is 100, calcium is 40 and carbonate 60. So a reduction of 78.6 mg/L in alkalinity will be 40% calcium, or 31.4 mg/L

[MattGuk]

I am quite amazed at how much reduction I had from the boil.
I have ordered a calcium test kit to make thing easier ( maths is not my strong point ).
I think when brewing lighter beer styles I will go with the boil method so as to not add too much in the way of Chloride and Sulphates in say a cream ale or Kolsch.
IPA's and bitters, I will go with CRS so I can bump those numbers up a little I think.