Magnesium in the water

[killer]

I wasn’t having a go at your logic Peebee I was just speaking generally. Why guesstimate when a short call ‘might’ give the answers.

JonB, there is a certain amount of splitting hairs here. We’re really looking for ranges of values and precision of +/- 5 ppm will have no effect on the beer. An average beer will have from 50 to 100 ppm Magnesium, much or most of which will come from the malt. Many brewers using RO water will add 5 to 10 ppm but don’t really know why other than they read it somewhere.
Most Calcium added in your water will be removed during the mash, sparge, boil and yeast flocculation. It has many many beneficial effects. I add a minimum 100 ppm Calcium in my mash and sparge liquors, but depending on my beer profile it could go up to 150 or 180 ppm. That’s fine too. As long as I’m in the right range (let’s say 100 – 200 pm) I’m happy. It will have also have an effect on the mash pH.
Are you adding acid to your water ? Do you measure mash pH ? You are probably lucky enough to have relatively low alkalinity which is the parameter that we are suggesting you test. Lots of homebrewers have high alkalinity of 200 ppm or more. The 10 ppm resolution in that case is relatively insignificant. My water swings between 160 and 280 ppm though, so I’m happy to have this figure. And that kit costs a tenner !

[JonB]

Thank you for that, I've been capping my total Ca to 150 mg/l (based on the estimated base Ca value of ~50mg/l) based on John Palmer's book, but if most of it's dropping out during the process and I can get away with up to 200 pre-mash/sparge as you suggest that give me a bit more flexibility.

I have started trying to measure mash pH in the last couple of brews as I've started experimenting with Chevallier which seems to require a more refined mashing technique (the Maris Otter I've generally used before appears to be extremely forgiving and I normally get mash efficiencies in the mid 80s). I got some strips from my local shop (which were worse than useless), and a digital pH meter is next on the list. The Brewer's friend calculator will work out from the data you put in how much of a specific acid you need to push the pH down to 5.4, so I've started adding acid in the last few batches. Generally my beer preference has been dark and roasty, so my predicted mash pH generally goes too far the other way. I've started brewing a lot of pale and hoppy styles in the last year or so but I'm not convinced the acid addition is having any material impact. I think generally leaving the mash overnight/whilst I'm at work as I often do as a timesaver probably explains a lot of that last bit...

[PeeBee]

@ PeeBee,
Thanks for beating me to it ...

Do remember my "safe guesstimate" was "safe" from a homebrewing point of view: i.e. it gives some Magnesium to work with but for brewing where Calcium or Magnesium isn't a big issue. But some UK tap waters can have 4:6 Mg/Ca proportions and that might not be so good for fish?

The other thing to bear in mind is while I've been brewing for decades, sorting my water out for nearly a decade, that "Total Hardness" thread started with me making a major blunder with "Hardness" ... and it's only two months old! It was sorting that blunder out when all the intricacies of water chemistry (in UK tap water) started clicking into place. I get worried when folk mention they are listening to me about some subject or other and lives (even if only fish) are at risk!

As I'm in "full disclosure" mode: The UK Government have a wonderfully non-PC term for me: "SMI"! (You'll need to Google it, but it gets me off paying Council Tax!). Not all bad, I'm amazed by the clarity in which I can imagine some things now (like "water chemistry"). Nothing like "Savant" level, but I find it remarkable all the same. Something else to bear in mind if applying my babbling to things having an impact on lives (even if only fish!).

I wasn’t having a go at your logic Peebee I was just speaking generally. ...

I did begin to realise I was probably being "over-sensitive". But at least I'm not reacting like you used to remember me!

[PeeBee]

... I've started experimenting with Chevallier which seems to require a more refined mashing technique (the Maris Otter I've generally used before appears to be extremely forgiving and I normally get mash efficiencies in the mid 80s) ...

A good move! I always suggest CAMRA should have started 50 years earlier to prevent the original demise of Chavallier barley malt and they would never have needed to fart about with "CO2".

But above normal care with water has never been my way with "Chavallier". But I am careful how it's mashed. Give it 90 minutes (60 isn't enough) and perhaps a bit cooler (63-65°C). The malting has been messed with recently and I don't think it needs treating as carefully as once was? Hop bitterness just "disappears"; I used it a lot with "Victorian" era recreations (they used a lot of hops back then).

[JonB]

No worries, I have more of an understanding around "SMI" (it's a poor term, I agree) than many, and I can follow your workings and they seem OK.

I will give Severn Trent a ring when I get chance and see if they can provide data for Ca and/or Mg, then I can get a good idea of the Mg/Ca proportions.

In all fairness my fish have been on this water for about 5-6 years and if there were harmful levels of ions (magnesium or otherwise) in the supply I would know about it by now. Some of them are quite old (for their species in a home aquaria), but they're all in pretty rude health...


EDIT: just seen your post about chevallier. All I meant is that I'm just being a bit more stringent with my Mash pH etc. to try and drive the efficiency up. In terms of water composition I've not done anything I wouldn't normally do (bar the acid addition to push the pH down to 5.4)

On my last batch it was actually your Chevallier thread I took my mash steps from (45 mins @ 63, 45 mins @ 69); previously I'd done a 60-min infusion mash not knowing any better and got 70% mash efficiencty (low for my system). The most recent batch is still fermenting but using your mash regime led to a jump to ~83% (more in line with "normal" batches with Maris Otter). Proof is in the tasting obviously but I'm quite excited for this one...

[PeeBee]

This might prove interesting. And not much interference from me! It got reopened and continued earlier this year, and skips from 2020 to 2023 within Page 1. Severn Trent again, this thread involves a bit of nudging them for more information which you may want to take note of. I'm not pushing my No Alkalinity, No Hardness approach in this one (well, I've only been pushing it a few weeks) so expect a bit more technical chatter in this!

viewtopic.php?f=9&t=83703

[JonB]

Thanks PeeBee,

I've had a read through it and it does make sense. When I get the chance I'll try and prod Severn Trent for more accurate figures, though I do get the impression from that thread they aren't really that bothered about what they put out...

[Eric]

Seriously, don't buy a kit to measure calcium and magnesium. leave it there.
When you have a fiver to spare, buy a TDS meter.
When you have a tenner to spare, buy a Salifert KH/Alk kit. By a simple ion balance of the major ions, it appears alkalinity is around 100 mg/L as CaCO3. However with 7 sodium tests with little variance compared with other measured ions, I don't have my usual degree of confidence and hence a Salifert KH test would answer that question.

PeeBee, take a sample for a KH/Alk test from your HLT before you mash in. This should have allowed some of the CO2 in solution to escape to lower pH. Let it cool sealed from the atmosphere. Add the indicator and charge the syringe accurately. place on a piece of white paper and swirl gently while adding the reagent in stages, continue swirling when it shows pink and initial will become grey of blue again. When it remains pink after swirling and note how pink it is. Leave it overnight and examine the following day. If it remains pink, the test was good, else it was influenced by CO2 dissolved in the sample.

100 ppm alkalinity as CaCO3, anybody wanting it in another type of unit can calculate it themselves, is too high for all pale beers and is on the upper limit for many darker beers except those that contain significant proportions of dark and crystal malts, like Imperial Stouts as mentioned by Killer.

Don't necessarily limit yourself to 150 ppm for calcium. What calcium primarily does for beer isn't to add flavour. It takes a full chapter to list its benefits, but 150 ppm isn't a bad starting point.

[PeeBee]

... PeeBee, take a sample for a KH/Alk test from your HLT before you mash in. This should have allowed some of the CO2 in solution to escape to lower pH. Let it cool sealed from the atmosphere. Add the indicator and charge the syringe accurately. place on a piece of white paper and swirl gently while adding the reagent in stages, continue swirling when it shows pink and initial will become grey of blue again. When it remains pink after swirling and note how pink it is. Leave it overnight and examine the following day. If it remains pink, the test was good, else it was influenced by CO2 dissolved in the sample...

Okay, thanks, I'll look at that.

You've forced me to check my information: Seems I picked up some dodgy information and the resolution is supposedly 0.1meq/l, not the 1meq/l I had. But I could believe 1meq/l (50ppm as CaCO3) 'cos one drop turned the my sample instantly pink! I'd also got [1meq/l = 30ppm] from somewhere a while back which negated some of the initial misinformation. "Wallybrew" tested at the time and my water was coming out as 8ppm as CaCO3. It's currently being reported as 14ppm as CaCO3 (Dwr Cymru). So it should now be able to take 3 drops (to indicate 10-15ppm as CaCO3).

But to be honest, even if I get something more sensible from these "Alkalinity Test Kits" by jumping through the hoops you've outlined, I'm not really going to start trusting these kits. And I'm not going to recommend anyone with "soft" water use them either!"



[EDIT: My initial error was converting dKH (as measured by the kit) to ppm (as "CaCO3"), not meq/l. And my kit expired in 2020 so I made the error a while ago! Interestingly, "dKH" reflects that the kit is measuring "Carbonate Hardness" and not, strictly speaking, "Alkalinity" ... that's just for anyone who thinks my "shortcut" thinking of "alkalinity" = "temporary hardness" (aka "carbonate hardness") is dodgy.]

[PeeBee]

... My initial error was converting dKH (as measured by the kit) to ppm (as "CaCO3"), not meq/l. And my kit expired in 2020 so I made the error a while ago! Interestingly, "dKH" reflects that the kit is measuring "Carbonate Hardness" and not, strictly speaking, "Alkalinity" ... that's just for anyone who thinks my "shortcut" thinking of "alkalinity" = "temporary hardness" (aka "carbonate hardness") is dodgy.

And ...

If "Strictly Speaking": "Carbonate Hardness" isn't "Temporary Hardness" either! Temporary Hardness doesn't include single valance cation carbonate and bicarbonate salts (like Sodium Bicarbonate).

I think I did describe "Hardness" as a mire of a subject earlier? The quicker we (as beer brewers) are shot of the soap suds "Hardness" subject, the better we'll be! It should take the equally daft "as CaCO3" with it too.

[PeeBee]

Thanks PeeBee,

I've had a read through it and it does make sense. When I get the chance I'll try and prod Severn Trent for more accurate figures, though I do get the impression from that thread they aren't really that bothered about what they put out...

A month on ...

Did you get anything from ST?

I've been keeping up the "water analysis" game following my conversation with you and can come to the conclusion [ST (edit)] are pretty grim, but I'm not saying "the worst" just yet (so I've not really come to a conclusion?).

As part of my trudging through "water analysis" I've written a spreadsheet to help. I'm giving up with the conductivity method of arriving at "Total Dissolved Solids" and have switched to "Cation/Anion Mass Balance" 'cos "conductivity" always seemed to arrive at too low a figure using the default factor of 0.65 and I could find no rules for ramping up the factor. The spreadsheet uses Mass Balance. This is what it throws out for you ...

South Sheffield.jpg (158.62 KiB) Viewed 2652 times

The spreadsheet attempts to strip out any stuff about arcane "Hardness" and associated "as CaCO3" measures and condenses the information as six well known ions (measured in mg/litre or ppm). One ion represents the "Alkalinity" (bicarbonate). The lower levels of the spreadsheet is the "Foetid Mire" which contains all the stuff like "Hardness" that are manipulated into common units that fit with the rest. Two additional compounds are included for balance purposes only: Nitrates and Phosphates. I'm not happy with where I'm going with "Phosphates", so best ignore that, however Nitrates often appear.

You can read more about the spreadsheet and download it >here<.

I'm dabbling with an 8:2 Ca/Mg ratio, and that with the substantial increase in "bicarbonate" compared to the earlier work I did for you is what I want to go over ... to get some confidence in what this spreadsheet is regurgitating!

Anything to add?

[JonB]

Hi PeeBee,

I've prodded them, but with everything going on recently I haven't done it as vigorously as perhaps I should have.

I have another brew I've done with the revised data worked out previously and that's due for bottling this weekend; I used the 1:9 Mg:Ca from the last page.

I'll try and give them another prod and see if owt comes of it...

[PeeBee]

Thanks. Sorry to bug you with it, just trying to judge the implications of the changes I'm introducing with this spreadsheet. The big change was switching to "mass balancing" as a more accurate way of judging "Alkalinity" than "conductivity". The only outcome of using my previous "manual" calculations is the mash pH might have been a tad higher than a water calculator might have otherwise predicted? Don't worry, I'm not expecting folk to understand what "mass balancing" is about, that's why it's in a spreadsheet (it was fusing my head - I don't want to inflict it on anyone unnecessarily).

Using 8:2 calcium/magnesium ratio (rather than 9:1) would barely make any difference to you (your water has a relatively low calcium content) but would let me know if my "assumptions" are on track (you've twice the calcium I have in my water). The ratio is an interesting one 'cos it's the ratio of "calcium carbonate" and "magnesium carbonate" (equivalents) not calcium/magnesium ions. Big changes to carbonates are much smaller as cations, and smaller still as more Mg gets included "as CaCO3".

And if that's all gooble-de-gook, do I need to remind you what I think of "as CaCO3"? ...

[Galena]

I'll try and give them another prod and see if owt comes of it...

I rang Severn Trent recently and they were very helpful. You need to speak to the Water Quality Team, they said I could ring any time I need the info and they are open 8am to 4pm Mon - Fri

Direct Line 024 777 16744

Their numbers were a little off what I got from Phoenix Analytical (though close enough for brewing purposes) but then I don't know where their sample was from so a difference should be expected I guess. Next time I will ask that question.

[cc986]

I contact Severn Trent about every 2 months or so by WhatsApp and ask for the latest figures for all minerals and they are always different to what they publish on the website for my area. The recent magnesium levels that they have given me are 42, 9, 10, 42, 9, 38 so you can see that they change quite a lot in a couple of months. They won't say exactly where they measure that in relation to where I live, but I think they struggle to be accurate due to the different sources for their water, so I tend to not get too concerned about it and find that if I measure the TDS and the calcium and carbonate/hardness/alkalinity using salifert kits I normally get very close.