Trying to decode the Thames Water report

[salnajjar]

I'm trying to use the Thames Water report for my area to get a rough idea of the additives I need (am going to manually test my pH balance each brew time).

The report report is here (warning, PDF): http://www.thameswater.co.uk/water-qual ... ODSIDE.pdf

Firstly, when I punch in my Alkalinity into the Liquor Treatment Calculator I get told that "Your intial carbonate level seems too high. Check carbonate reduction parameters", is this just warning me that I have very hard water? (mgl CaCO3 (ppm) = 275.5)

Secondly, I can't seem to find my magnesium levels listed on that site anywhere, is this is easy to do a manual test on?

Lastly, if I select "General Purpose" from the list then it tells me I only need to add magnesium (no doubt because I've left that part blank), is this right?

Thanks for any help

Seri

[Graham]

People will probably need a bit more information before a useful reply can be given.

How are you going to reduce your carbonate? Are you going to boil or use CRS? There are pros and cons to both methods. Specifically, there are some water profiles that cannot be matched when using CRS, depending upon your initial water. It is quite likely in your case, that you will not be able to match some waters because you have lots of chalk in your water, which means that CRS will add lots of sulphate and chloride as a consequence of neutralising the carbonate. Those levels may be higher than the target water you are trying to achieve.

How did you arrive at an alkalinity figure? Did you measure it yourself with a test kit? Thames water do not give alkalinity in their table, just hardness, which is not the same thing. It is only important when using CRS, but in that case it is better to measure it. A figure given by the water company, in the rare cases they feel inclined to do so, is only approximate and often not stable enough because the level can vary from day to day. The daily fluctuations can exceed the target residual alkalinity of about 20mg/l carbonate (CO3) as recommended by Brupaks for example. There is not much margin for error.

Not having a figure for magnesium is no big deal. It does not impact on anything serious. The yeast requires a small amount of magnesium to give it strong bones and healthy teeth. As long as there is more than about 5mg/l in your final liquor, that is good enough. There might be enough naturally, but it is not worth risking a magnesium deficiency for the sake of a pinch of inner cleanliness. Having too much, within reason of course, is not going to hurt anything.

[salnajjar]

Graham, thanks for the reply, I'm slowly starting to get an understanding of the water side of things (it seems more complicated than the actual brewing!).

I had mistakenly taken the reading on the water report of hardness and thought that was the Alkalinity.

So, I guess my bigger question is how to test the Alkalinity of the water... I had originally thought I could simply use pH test strips but it appears that you have to be a lot more precise than that. Is there a beginners primer to water treatment on this wonderful website of knowledge? Hopefully if there is such a thing then it will help me also understand the benefits and pitfalls of CRS/Boiling.

Thanks again

Seri

[Graham]

salnajjar,

Water treatment can be as easy or as complicated as one wants to make it. In its basics all that is necessary is to ensure that there is sufficient calcium for brewing reactions - about 100mg/l I regard as about right as a minimum. The other requirement is that mash pH is within a normal range and that normally requires getting the carbonate down to lowish levels. To go any further than that is getting into the realms of fussiness. The chloride-sulphate ratio impacts upon flavour, but there is no such thing as a wrong ratio. There is no harm in using the chloride-sulphate ratio that you end up with and there is no point in loosing any sleep over it.

Alkalinity is the carbonate column in the water calculator, but it can be expressed in various ways, usually calcium carbonate, but it needs to be converted to carbonate for the calculator. That is basically all the alkalinity box does - the conversion. Although hardness and alkalinity are not the same thing, alkalinity can be approximated from hardness. I have done the calculations on your water and I reckon your water is:

Calcium=111 mg/l
Magnesium=0
Sodium 24.3
Carbonate=136
Sulphate=48
Chloride=37.7

The sulphate and chloride figures do not exactly match the Thames Water numbers because the table shows averages and does not represent an ionicaly balanced water. It is not far out, as it happens. Magnesium is zero because we have no way of determining what it is. It will not be much, and it doesn't matter anyway. The carbonate figure will probably not be accurate enough for using CRS; indeed, they only took two hardness measurements during the year and that is not statistically good enough to have any degree of certainty over the accuracy of the numbers. The two days they decided to make a measurement the water could coincidentally have been much closer than normal.

Anyway, putting those numbers into the water calculator will give you the opportunity to experiment with the calculator. You will observe that if you select CRS for carbonate reduction, you will not be able to match most of the water profiles, mostly because chloride and sulphate ions are added by CRS in a fixed ratio. You will not be able to get the calcium below 111mg/l either, but there is no reason why that should be a problem. With boiling you are starting with a cleaner slate and can match just about anything. If you wish to use CRS it is probably best to stick with what you end up with and not worry about it.

[salnajjar]

Graham, you are a star.
I had gone off and done some research when I couldn't sleep last night on CRS and found the handy dandy PDF on this website on how to use CRS to measure your water to begin with. I did then also play around with the water calculator some more and had noticed that it expected me to know the Chloride:Sulfate ratio.

I guess I'm being extra pernickity because this is going to be my first AG brew and I want it all to be perfect.

Using the calc for 23l water I get:
3.69g Calcium Sulphate
2.74g Calcium Chloride
4.66g Magnesium Sulphate

Does this sound about right?

Also, (sorry about all the questions) if I do decide to go the CRS route, then how do I know my sulphate to chloride ration? I've worked out how to accurately measure my Alkalinity (luckily I have scales that are accurate to 0.01g).

Thanks again, just for the info already provided, it's been really helpful.

Seri

[Graham]

It is difficult to say if it looks right without knowing what you are setting out to achieve. For some reason your magnesium sulphate seems to be about twice as much as is necessary, but that won't hurt; the rest seems reasonable. It seems that you have selected boiling as your method of carbonate reduction. It will be a different thing if you selected CRS. Bare in mind that you will need more water than 23 litres if you are looking for 23 litres of beer. About half as much again to be safe.

When using the CRS method to measure alkalinity you will probably have difficulty obtaining the methyl-orange indicator required, so that method may not be available to you. Instead, many people use the Salifert kH Hardness / Alkalinity test kit, which is available from tropical fish shops for about £7. The "hardness" part of the title is a bit of a misnomer; it does not really measure hardness, but alkalinity. At least they are now putting "alkalinity" on the box - they never used to and it caused confusion.

When using CRS you will not have much control over chloride:sulphate ratio. You will have to be content with what you end up with. You can work out the sulphate:chloride ratio you've got from the figures in the final liquor boxes. CRS is a mixture of two acids in fixed proportions, and is therefore inflexible. It would be preferable if the two acids were available to us separately, then we would have complete flexibility - but we haven't got that advantage currently.

[salnajjar]

Sorry, I had the calc set to "General Use" as I thought that was the safest middle of the road setting until I decide on what I'm going to try for my first AG brew (probably a Golden Glory clone).

I've been looking into the Salifert kits, seems as if all the aquatic suppliers online try and stiff you with the postage so I may have to go to my local aquarium shop and see what price they have it in stock at.

One of the things I was wondering was if I used CRS to reduce the Alkalinity down to about 20 or 30 ppm then would it be best to add the additional additives as if I had just done a boil treatment anyway?

Thanks again

Seri

[Graham]

One of the things I was wondering was if I used CRS to reduce the Alkalinity down to about 20 or 30 ppm then would it be best to add the additional additives as if I had just done a boil treatment anyway?

No, not in your case. If you put your water info into the calculator and select CRS as carbonate reduction, you will notice that all the additions apart from magnesium sulphate go away. You will also notice that you cannot exactly match general-purpose water. When you boil the water both calcium and carbonate are reduced considerably; and nothing is automatically added. When using CRS the calcium stays the same, carbonate is reduced, but sulphate and chloride ions are added by the CRS. You will have enough calcium, your carbonate will be down to where you want it, but you will have to put up with the chloride-sulphate ratio that you end up with.

In theory at least, CRS adds too much chloride for pale ales, but perhaps too much faith is placed on chloride-sulphate ratios anyway. It will be fine, certainly for a first all-grain attempt.

[salnajjar]

Graham, thanks again for all your help.

Seri

[salnajjar]

I've just tested my water with the Salifert KH test kit.

The results are: 12.0 dKH / 4.28 meq/L

Am I correct in assuming that I punch into the calculator 428 ml CaCO3 in the Alkalinity section and leave the hardness section blank?

If so, I get a carbonate CO3 measurement of 256.62 which the calculator tells me is quite high.

Is this correct?

I will be testing my water before each brewing session, but I want to make sure I know what I'm doing first.

Thanks

[adm]

I've just tested my water with the Salifert KH test kit.

The results are: 12.0 dKH / 4.28 meq/L

No. You need to convert the 4.28 meq/L figure into mg/L CaC03......which is fortunately just a straight multiply by 50. So your Total Alkalinity value would be 4.8 x 50 = 214 mg/L CaCO3.

So stick 214 into the Alkalinity section - and yes, leave the hardness blank.

[Graham]

I've just tested my water with the Salifert KH test kit.

The results are: 12.0 dKH / 4.28 meq/L

Am I correct in assuming that I punch into the calculator 428 ml CaCO3 in the Alkalinity section and leave the hardness section blank?

If so, I get a carbonate CO3 measurement of 256.62 which the calculator tells me is quite high.

Is this correct?

I will be testing my water before each brewing session, but I want to make sure I know what I'm doing first.

Thanks

No, multiply your 4.28 meq/l by 50 (=214) to express as it calcium carbonate, or multiply 4.28 by 30 (=128.4) to express it as carbonate.