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Taste threshold for phosphoric acid

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Simonh82

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I've been playing around with Bru'N water to work out what I need to do with my mash water. I'm about to start all grain BIAB and want to get these things right straight away.

My hard, hard London water has very hight bicarbonate levels (total bicarbonate of 611ppm) so I need a lot of acid to counter this and get the mash PH into range.

I'm going to use a mixture of Brupacks Carbonate Reducing Solution CRS (sulphuric and hydrochloric) and Phosphoric to get it in to range. I know that phosphoric is meant to give very low taste but I'm still getting a warning that 18ml I will be using between the mash and sparge water will be above the taste threshold. I can't really add more CRS as it will send the Sulphate levels too high.

Any suggestions which don't involved dilution with RO/distilled water? You seem to be able to pick this up for pennies in the States but using a significant quantity of purchased water would really up my brewing costs significantly.
 

Yooper

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Before I got an RO system, I tried lime softening. Your water may be perfect for that, and it's easy.

It involves adding pickling lime, stirring well, and just racking the water off of the precipitate. I can post a link later, if you'd like.
 
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Simonh82

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I think pickling lime will take my water in the wrong direction. It is a strong alkali. I need to acidify my water but I don't want to add any strange tastes from the acids.
 

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BlackFurnaceBrewing

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I've been playing around with Bru'N water to work out what I need to do with my mash water. I'm about to start all grain BIAB and want to get these things right straight away.

My hard, hard London water has very hight bicarbonate levels (total bicarbonate of 611ppm) so I need a lot of acid to counter this and get the mash PH into range.

I'm going to use a mixture of Brupacks Carbonate Reducing Solution CRS (sulphuric and hydrochloric) and Phosphoric to get it in to range. I know that phosphoric is meant to give very low taste but I'm still getting a warning that 18ml I will be using between the mash and sparge water will be above the taste threshold. I can't really add more CRS as it will send the Sulphate levels too high.

Any suggestions which don't involved dilution with RO/distilled water? You seem to be able to pick this up for pennies in the States but using a significant quantity of purchased water would really up my brewing costs significantly.

I brewed with similar water to yours for years before moving to an RO system. I have used citric, phosphoric. lactic, sulfuric ad hydrochloric acids....sometimes all in one batch. You will find IPA's to be your friend as they can take a lot of sulfate.

To answer your question, keep your phosphates below 900 ppm and you should not create any noticeable flavor.

If you care to post your beer style and water profile here, I'm sure we can dial you in.
 
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Simonh82

Simonh82

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I brewed with similar water to yours for years before moving to an RO system. I have used citric, phosphoric. lactic, sulfuric ad hydrochloric acids....sometimes all in one batch. You will find IPA's to be your friend as they can take a lot of sulfate.

To answer your question, keep your phosphates below 900 ppm and you should not create any noticeable flavor.

If you care to post your beer style and water profile here, I'm sure we can dial you in.
This is good to hear. The total phosphate is 567ppm so hopefully it won't impact on the flavour. If it does I will see if I can find some Malic acid which might work too.

Pale hoppy beers are definitely my preferred style so this is also good. I know the traditional approach to this type of water is to brew dark malty beers to get the acidification from the malt but this isn't really what I like drinking.

Thanks for the advice.
 

mabrungard

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I think pickling lime will take my water in the wrong direction. It is a strong alkali. I need to acidify my water but I don't want to add any strange tastes from the acids.
You are correct...its counter-intuitive to add a strong alkali to an alkaline solution. However, adding that strong alkali causes a strong precipitation reaction that takes not only the calcium with it, but also takes some of the carbonate alkalinity with it. With the carbonate content reduced, it is then fairly easy to knock the remaining water alkalinity down with either recarbonation (bubbling CO2 through the water) or acid addition or both.

Lime softening is used around the world for softening waters that are chemically suited for it. Those waters have high temporary hardness and low permanent hardness.
 
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Simonh82

Simonh82

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Thanks everyone. Lime softening does seem like an interesting option. I see that it can also reduce magnesium levels if you get the pH high enough. My magnesium level is 61ppm an I just figured I would need to live with this.

I will try brewing just with acid additions and see if I can detect any appreciable flavour.

If it causes problems I can use lime softening but I prefer the simplicity of acid additions.

Thank you all for your help.
 

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Thanks everyone. Lime softening does seem like an interesting option. I see that it can also reduce magnesium levels if you get the pH high enough. My magnesium level is 61ppm an I just figured I would need to live with this.

I will try brewing just with acid additions and see if I can detect any appreciable flavour.

If it causes problems I can use lime softening but I prefer the simplicity of acid additions.

Thank you all for your help.
Oh, that magnesium is definitely too high- you'll have a flavor impact for sure. You want to reduce that by more than half.

Acid additions will definitely reduce the alkalinity of your water, but the only fix for things like excess magnesium will be diluting with RO water (by more than 50%) or such things as lime softening. I'm no chemist, and I don't know if you can reduce your magnesium enough (probably not without a two-stage reduction; but that is a question more for @mabrungard and not me!) so it does sound like a combination of dilution and acid additions may be your only option.
 

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Yes, the 'split system' of lime softening will remove about half the magnesium. The idea is to treat about 2/3 the water with lime sufficient to decarbonate the entire volume. The extra lime increases the pH to the point where Mg(OH)2 precipitates. One then decants the reduced magnesium water and neutralizes the excess lime with the 'acid' bicarbonate in the remaining third. Clearly the best that can be done here is 2/3 reduction but in practice that high a reduction won't be realized. To do it right requires careful calculation of the lime dose and a pH meter to monitor the neutralization. The treated water then needs to be tested to see if the desired magnesium and alkalinity reductions have in fact been attained. DeClerck suggests small scale tests with the calculated lime amount and the calculated amount ± 10%.
 

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Yes, the 'split system' of lime softening will remove about half the magnesium. The idea is to treat about 2/3 the water with lime sufficient to decarbonate the entire volume. The extra lime increases the pH to the point where Mg(OH)2 precipitates. One then decants the reduced magnesium water and neutralizes the excess lime with the 'acid' bicarbonate in the remaining third. Clearly the best that can be done here is 2/3 reduction but in practice that high a reduction won't be realized. To do it right requires careful calculation of the lime dose and a pH meter to monitor the neutralization. The treated water then needs to be tested to see if the desired magnesium and alkalinity reductions have in fact been attained. DeClerck suggests small scale tests with the calculated lime amount and the calculated amount ± 10%.
Thanks for the clarification, AJ!
 
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What effect does lime softening have on the calcium levels of the water? My calcium is about 100 ppm. If the lime soft precipitates calcium carbonate how much will this lower my calcium levels?

Sorry, chemistry is my weakest science and I don't even pretend to understand the numbers behind these reactions.
 

ajdelange

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As indicated in #10 you really have to experiment and test for best results (with 'best' usually meaning maximum reduction in alkalinity) but as a rule of thumb the smaller of the calcium hardness and alkalinity will be reduced to 1 mEq/L (50 ppm as CaCO3). Both calcium hardness and alkalinity are reduced by the same amount in units of mEq/L or ppm. Thus if calcium hardness is 110 ppm (2.2 mEq/L, 44 mg/L) and alkalinity 150 ppm calcium hardness (the smaller) will be reduced to 50 by loss of 60 ppm and alkalinity then will also be reduced by 60 to 90 ppm. In such cases one simply supplements the calcium to make the hardness number greater. In this case the brewer might add CaCl2 or gypsum to get calcium hardness equal to the alkalinity i.e. to 150 ppm. Lime softening (or boiling) would then reduce both alkalinity and hardness to 50 ppm. Adding even more calcium (enough to get it appreciably larger than the alkalinity) makes it possible to get alkalinity to less than 1 mEq/L (50 ppm).
 

mabrungard

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What effect does lime softening have on the calcium levels of the water? My calcium is about 100 ppm. If the lime soft precipitates calcium carbonate how much will this lower my calcium levels?

Sorry, chemistry is my weakest science and I don't even pretend to understand the numbers behind these reactions.
The practical limit for Ca concentration is around 12 ppm and that requires that there is enough alkalinity content in the water to match the Ca that is precipitated out.

In other words, if the water has high temporary hardness and low permanent hardness, lime softening can probably get your calcium content down into the 12 to 20 ppm range. Your technique has an effect on how low you can get the Ca level.
 

ajdelange

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The practical limit for Ca concentration is around 12 ppm and that requires that there is enough alkalinity content in the water to match the Ca that is precipitated out.
In #13 I indicated that one could decarbonate below 1 mEq/L by increasing calcium. This works because

[Ca++][CO3--] < 10^-8.45

Thus the more Ca++ is in solution the less carbonate can be present before precipitation of CaCO3 occurs.

One can, of course, turn this around if the goal is to decrease calcium (soften) the water and increased alkalinity is tolerable. This is rarely the case. Calcium is usually considered beneficial and alkalinity is usually a problem though there are some cases where it is needed. In such cases one usually wants to preserve calcium though there are beers where very little calcium is traditional.

If one really wants to get rid of calcium the best bet (other than RO) is to add PO4---. This used to be commonly done with 'washing soda', Na3PO4 but is no longer because of the bad environmental effects of phosphates on rivers and streams. Ca10(PO4)6(OH)2 is extremely insoluble (much less so that CaCO3) and so phosphate scavenges calcium very effectively.
 
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