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-   -   Would like to get some input from the water gurus, please. (http://www.homebrewtalk.com/f128/would-like-get-some-input-water-gurus-please-446487/)

mblanks2 12-06-2013 10:35 AM

Would like to get some input from the water gurus, please.
Ward Labs Report:
pH 7.9
Total Dissolved Solids (TDS) Est, ppm 126
Electrical Conductivity, mmho/cm 0.21
Cations / Anions, me/L 2.2 / 2.1
Sodium, Na 14
Potassium, K 2
Calcium, Ca 21
Magnesium, Mg 5
Total Hardness, CaCO3 73
Nitrate, NO3-N 0.4 (SAFE)
Sulfate, SO4-S 6
Chloride, Cl 10
Carbonate, CO3 < 1
Bicarbonate, HCO3 85
Total Alkalinity, CaCO3 69

Good, Bad, Indifferent? I do not dilute. I am using Bru'n Water for adjustments and trying to learn as much about water chemistry as possible. I seem to be able to hit my mash PH very closely if not dead on, every time. I am always able to get Ca, Mg, Na, SO4, and Cl in the "Recommended Ranges" for the styles, but my RA is always negative by the spreadsheet. What does this mean? What effects is this going to cause or is it an issue at all? Thanks in advance for your insight.

mchrispen 12-06-2013 01:04 PM

I am hardly a water guru... but at a glance that is very good water for brewing in general. For paler beers you may need to add some acidity, but I suspect with some mineral additions it may come in line just fine. Since you are familiar with Bru'n Water - that should not surprise you at all. I am quite jealous.

When I use RO water, I also get a negative RA number, and as long as it isn't huge, I pretty much ignore it as long as your pH prediction is inline with your expectations. If it is massive, I will likely need to add pickling lime or soda into the mash for alkalinity. I believe it is much more critical when you have a ton of alkalinity as bicarb that must be overcome. With your alkalinity and a few acid additions, it will drop below 0 quickly, as the acid from the grist and the mineral additions (Ca) will overcome it. In practice it should be relatively easy for you to manipulate your mash pH quickly should you need to (and I assume you have a calibrated pH meter).

A more detailed explanation of RA is on the Bru'n Water Knowledge page here https://sites.google.com/site/brunwater/water-knowledge in section 2.4.

mabrungard 12-06-2013 01:34 PM

That is a great starting point for brewing water. All flavor ions are low and the only thing of concern is the alkalinity. I can say that this water might be a better starting point than RO water is since there is that alkalinity in the tap water. That is an easy adjustment away. Just add an acid to neutralize in those mashes that don't need it. Of course, all sparging water needs the acidification since that amount of alkalinity is a bit too high for that usage. Almost any acid will work since the amount needed is small enough to generally avoid taste effects...even lactic acid.

As Matt mentions, there are mashes where you might need that alkalinity. He and I use RO and there is the need for baking soda or lime in the mash to keep the mash pH up in a proper range. This tap water might avoid that need in most cases.

mblanks2 12-07-2013 12:01 PM

Thank you very much for your comments. I have been using this water for all of my brewing and I do have a calibrated PH meter that I keep stored in storage solution.
The acid adjustments I make tend to be mostly 25% phosphoric with some salt additions such as Gypsum and Calcium chloride to bring everything listed above into the range of the selected profile.
It was just the RA being my main concern. I've hit Mash PH nearly perfectly every time I use the Bru'n Water spread sheet but have hit RA numbers as low as -90 as mg/L as CaCO3 or -33 as ppm as CaCo3. Which of these numbers are of concern and what effect will this have. Can there truly be negative alkalinity?
Again I am a complete novice when it comes to water and am just trying to understand. I am a "Type A perfectionist" which can be a detriment at some times, I just want it right and want to know why things are what they are.
The beer has been awesome by the way.

ajdelange 12-07-2013 01:34 PM

Can there be negative alkalinity? Absolutely. It is called 'acidity'. The formal definition of alkalinity is the amount of acid that you must add to a unit amount of substance (a liter of water or a kilogram of malt, for example) to bring its pH from the pH at which it is presented to you (intrinsic pH) to a target pH of interest (mash pH, for example). Water presents at some pH between, say, 6 and 9 and in mashing we need to reduce that to, e.g. 5.4 and we must add acid to it to do that. For your water we would have to add 1.26 mEq to each liter to bring its pH to 5.4. The alkalinity of your water with respect to mash pH of 5.4 is, thus, 1.26 mEq/L. The alkalinity with respect to pH 4.5 is 2.38 mEq/L which, multiplied by 50, gives 69. When the guy in the lab measured your water he added acid until the pH dropped to pH 4.5 then multiplied the mEq/L by 50 (half the molecular weight of calcium carbonate) as we do in North America.

The alkalinity of a base malt (Weyermanns Pils) that has a distilled water pH of 5.62 requires that 31.2 mEq of acid be added to each kg of it to lower it's pH to 5.4. It's alkalinity is 31.2 mEq/kg WRT pH 5.4. But Weyermann's 80L Caramel malt has a DI water pH of 4.77. To get its pH up to 5.4 you must withdraw protons from it. In fact you must withdraw 15.64 mEq/kg. It's alkalinity is, therefore, -15.64 mEq/kg WRT pH 5.4. In summary, alkalinity is the number of protons that must be added or subtracted to effect pH change. If the pH is from higher to lower the alkalinity is a positive number. If it is from lower to higher it is a negative number. The magnitude of negative alkalinity is called 'acidity'. Protons are withdrawn by adding a base which is anything which absorbs protons. The bases in a mash are 1) any malt with a positive alkalinity (proton deficit), 2) the bicarbonate in the water (water's positive alkalinity and positive proton deficit) and 3) any substances you add with a positive proton deficit (alkalinity) to increase alkalinity such as sodium bicarbonate, sodium carbonate, lime or lye. In the majority of cases the base malt and water bicarbonate absorb more protons than the colored malts donate at reasonable pH and you must add another source of protons (such as phosphoric acid, lactic acid, sauermalz or another highly colored malt) to have total donated protons equal number of absorbed protons at an acceptable pH. The one thing I have not mentioned so far is that calcium in the water reacts with malt phosphate releasing protons. Calcium, thus, appears to have a negative alkalinity associated with it and back in the early 1940's a German brewing scientist (Paul Kohlbach) proposed subtracting this acidity (adding the negative allalinity) to the alkalinity of the water. The result is the residual alkalinity. If you use RO water and add any calcium to it you will have a negative RA. This does not by any means indicate that you need to add base. That depends on the relative amounts of the various grains and their properties: DI mash pH's and, equally important, their buffering capacities. If you have these data it is a relatively simple matter to predict and control mash pH by toting up the proton deficits of each mash component. The problem is getting those data. Getting a set of data on a particular malt is an arduous process and there is no guarantee that your sack of Weyermanns Pils will measure the same as mine unless they are from the same lot number. This has led people that produce mash pH predicting calculators to try to derive malt parameter data from malt color and based on experimental data on a handful of malts measured by the guys that pioneered this work. The results are very approximate but still useful as long as one checks up on them by using a pH meter.

mabrungard 12-07-2013 03:25 PM

A negative RA or alkalinity value is not a surprise. Even a Pils malt mash in distilled water will need about 100 ppm of protons (aka: negative bicarbonate in Bru'n Water) to reduce its normal mash pH from about 5.7 to 5.4. Don't worry about those negative values when dealing with pale grists. It's only when you get into more acidic and darker grists that the need for negative RA water is not needed.

mblanks2 12-07-2013 03:48 PM

Thanks all. This has be very informative and reassuring regarding my water and the treatments I am currently working with. Thanks again, all. Excellent information.

ajdelange 12-07-2013 04:12 PM


Originally Posted by mabrungard (Post 5724194)
Even a Pils malt mash in distilled water will need about 100 ppm of protons (aka: negative bicarbonate in Bru'n Water) to reduce its normal mash pH from about 5.7 to 5.4.

Could you explain the units here please? For the Pils malt (Weyermanns) I did measurements on I found that it would take 15 mEq of protons to lower the pH of 1 kg of this malt from its DI mash pH (5.62) to 5.32 (0.3 units as in your example). In another post you spoke of proton deficit of water as being 100 ppm and I assumed it meant as CaCO3 i.e. 100/50 = 2 mVal (2 mEq/L) but that doesn't match up to 15 mEq/kg in any way I can figure out.

mabrungard 12-07-2013 08:52 PM

For each excess bicarbonate ion, there needs to be a hydrogen proton to neutralize it. To simplify the presentation in Bru'n Water, that is shown as a negative bicarbonate concentration. Sorry for not converting it to a real concentration.

ajdelange 12-07-2013 09:37 PM

Still confused. I get that you are expressing acid as negative base and that the base is bicarbonate ion. Then 100 'parts' (mg) of bicarbonate would equate to 100/61 = 1.63 mEq protons i.e. 100 mg of bicarbonate absorbs 1.63 mEq of protons and -100 mg of bicarbonate would yield 1.63 mEq of protons. OK on the 'parts'. But I'm confused about the 'per million' - per million what? Given that it takes about 15 mEq of acid to shift 1 kg of Pils malt 0.3 pH 1.63 mEq would shift a bit more than 100 grams. 100 mg/100 grams is 1 ppt or 1000 ppm. So if you had said '1000 ppm as bicarbonate' I'd probably have been able to figure it out but it would be much clearer if you said "15 mEq/kg" (or whatever your model gives) or "915 mEq/kg as bicarbonate" or "915 parts bicarbonate equivalent per million parts malt". I still don't understand the factor of 10 though.

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