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Old 11-18-2010, 09:52 PM   #31
ajdelange
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Originally Posted by funkswing View Post
What does a negative RA mean?
RA = alkalinity - (calcium_hardness + magnesium_hardness/2)/3.5

It is the alkalinity which is not "neutralized" by hydrogen ions released when calcium (and, to a lesser extent magnesium) reacts with malt phosphate. Distilled water has no alkalinity (well, it does actually have a wee bit but that's a technicality arising out of how it is defined and measured) so if you add even a small amount of calcium chloride or calcium sulfate these could react with malt phosphate to produce hydrogen ions which could neutralize more bicarbonate than is present. Thus, the RA is < 0.
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Old 11-18-2010, 10:04 PM   #32
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Originally Posted by ajdelange View Post
RA = alkalinity - (calcium_hardness + magnesium_hardness/2)/3.5

It is the alkalinity which is not "neutralized" by hydrogen ions released when calcium (and, to a lesser extent magnesium) reacts with malt phosphate. Distilled water has no alkalinity (well, it does actually have a wee bit but that's a technicality arising out of how it is defined and measured) so if you add even a small amount of calcium chloride or calcium sulfate these could react with malt phosphate to produce hydrogen ions which could neutralize more bicarbonate than is present. Thus, the RA is < 0.
So do my numbers look okay in my posts above? My final water profile is this: calcium level is right around 100. Chloride and sulfate both around 80. Magnesium is below 5. Sodium is below 10. RA is negative and effective hardness is 68.
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Old 11-18-2010, 10:50 PM   #33
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ajdelange - that's what I assumed. But...

Quote:
which could neutralize more bicarbonate than is present.
Doesn't make sense, because if the HCO3 isn't present, then it isn't going to be neutralized. So a -RA is bogus in application. It means that your mash pH is going to drop, yes (because of H+ going into solution), but negative alkalinity is not something that actually exists. That's why I asked.


Ben_Persitz - you are prolly doing everything right with the spreadsheet (but its a spreadsheet; use it as a guideline. Its not a mechanistic aqueous speciation model).

Looking at your water data, I wouldn't even dilute with distilled water. But I guess your hardness is a bit high.

Just brew it the way you want to brew it. Then post back here with your results. Your salt additions aren't going to ruin the pale ale. But we would all love to hear your results.
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Old 11-18-2010, 11:00 PM   #34
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ajdelange - that's what I assumed. But...


Doesn't make sense, because if the HCO3 isn't present, then it isn't going to be neutralized. So a -RA is bogus in application. It means that your mash pH is going to drop, yes (because of H+ going into solution), but negative alkalinity is not something that actually exists. That's why I asked.


Ben_Persitz - you are prolly doing everything right with the spreadsheet (but its a spreadsheet; use it as a guideline. Its not a mechanistic aqueous speciation model).

Looking at your water data, I wouldn't even dilute with distilled water. But I guess your hardness is a bit high.

Just brew it the way you want to brew it. Then post back here with your results. Your salt additions aren't going to ruin the pale ale. But we would all love to hear your results.

It'll be awhile, but will do!
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Old 11-18-2010, 11:03 PM   #35
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Please take your time. Remember, "Tasty, not hasty" (copyright 2010)

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Old 11-19-2010, 04:02 AM   #36
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Doesn't make sense, because if the HCO3 isn't present, then it isn't going to be neutralized. So a -RA is bogus in application. It means that your mash pH is going to drop, yes (because of H+ going into solution),...
Neutralize in this context is not the same as in the usual meaning (that's why I put it in quotes) but it is similar. In the usual meaning, to neutralize means to add enough acid or base to a solution to bring it's pH to the point where the solvent is dissociated to the point where there are equal numbers of its cations and anions in solution i.e. 7 for water at 25 °C. In the context of RA "neutralize" means to add as much acid or base to a mash made with the water in question as is necessary to bring its pH to the pH of a mash with the same grist but doughed in with distilled water. If a water contains a lot of bicarbonate but little calcium or magnesium it will take acid to do this and we call the RA positive. If the water contains a lot of calcium and/or magnesium it will take base to get to the pH of a distilled water mash - not that we would want to do that but if we did, that's what we would have to do. Addition of base is the same as the subtraction of acid. Each OH- added combines with an H+ to form water or, if HCO3- is used as the base, to form H2CO3 (a small adjustment is needed for the effects of pH shift) and so we call the RA negative if the mash pH with the water in question is less than the DI water mash pH. It is perfectly valid to have water with negative RA and the best example of water that does is the water of Burton on Trent but Dortmund, Edinburgh and Vienna (according to commonly available water reports for those cities) also do. There is a chart at http://www.pbase.com/agamid/image/57446374 that plots several well known brewing cities by effective hardness vs. alkalinity. Lines of constant RA are drawn on this chart from which one can determine the RA associated with any combination of effective hardness and alkalinity.

RA is, of course, ultimately a model and a model is valid if it allows us to predict something. RA is validated because it predicts, at least approximately, the pH of a base malt mash and it does this equally well when RA is negative as it does when it is positive. If it didn't, it would not represent a valid model and we wouldn't be talking about it.

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but negative alkalinity is not something that actually exists. That's why I asked.
I'm sure you meant to say that negative residual alkalinity doesn't exist but just in case you did mean alkalinity I'll point out that it is possible to have negative alkalinity for the same reason that it is possible to have negative RA. Alkalinity is defined as the amount of acid that must be added to a sample to lower its pH to some agreed upon pH. Unfortunately, there is more than one agreement out there so in brewing I use 4.3 irrespective of the water's composition. The other approach is to titrate until the number of hydrogen ions is equivalent to bicarbonate. Using 4.3 as the titration end point it should be clear that any sample with pH > 4.3 at the outset will require the addition of acid to lower the pH to 4.3. Such samples have positive alkalinity. But any sample with an initial pH < 4.3 (don't brew with such water!) would require the addition of base to raise the pH to 4.3 and such a sample would be said to have a negative alkalinity. You will never see negative alkalinity (water chemists would titrate with base to pH 7 and call the result acidity) but in terms of being able to calculate the actual sample chemistry of a carbo only system, a negative alkalinity or a positive acidity are equally informative.

Maybe another way to look at it is in terms of your bank balance which can be (but we hope is not) negative. A positive bank balance is the amount of money you can take out to bring the balance to 0. A negative balance is the amount of money you have to put in to avoid a nasty call from the bank manager. No, there are no dollars in the account when the balance is negative but you certainly had better not ignore a negative balance on this basis.
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Old 11-19-2010, 04:03 PM   #37
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ajdelange - I will read your post later (too busy), but thanks for taking the time to explain. So, "RA" is a brewing "chemistry" term and not a general chemistry theory?

That's cool, it just didn't make sense for me in theory. Mathematical of course it does, but math isn't theory or reality, its a tool.

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Old 11-19-2010, 04:07 PM   #38
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Yes, the term is due to Kolbach.

The paper where Kolbach introduced RA is available for download on AJ's website.

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Old 11-20-2010, 06:39 AM   #39
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Can anyone answer this question? As the poster mentioned, it would be extremely helpful to those of us that aren't into the chemistry.

Is it impossible to answer appropriately or something? All we need is a baseline to work from and a list to cover most basic styles.

The IKEA reference is perfect

Quote:
Originally Posted by ghpeel View Post
Ok I've re-read that, still not groking it 100%, but here's a stab at another way of listing itL:

Pilsner or soft water styles: 1/2 tsp calcium chloride, 3% sauermalt
American Pale Ale: 1 tsp calcium chloride, 1 tsp gypsum, 2% sauermalt
British Pale Ale: 2 tsp calcium chloride, 1 tsp gypsum, 2% sauermalt
Hoppy/Strong British Ale: 4 tsp calcium chloride, 2 tsp gypsum, 2% sauermalt
Porter or Stout: 1 tsp calcium chloride (no sauermalt)
Cascadian Dark Ale (hoppy): 1 tsp calcium chloride, 1 tsp gypsum (no sauermalt)

Are these right? What about Hefe's, do they fall into the soft water style?

What about: Wits, Belgians, or Irish Red's where do they fall?

A listing of all the BJCP styles and the adjustments needed to RO water to get a proper baseline would really be helpful to a lot of folks. Water chemistry is (to me anyway) by far the most complex part of brewing I've had to deal with.
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Old 11-20-2010, 04:15 PM   #40
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Thanks for the info!

Regarding the learning aspect... I learn much easier when I have the basics laid out... At least when I start out. It will give me and a lot of other folks a great foundation to start experimenting from.

I would personally be happy with with a short list, maybe 'ipa, light ale, porter and hefe'. I/we are not asking for a final answer on this... Just a starting point so we don't make 10 'dumpers' right of the bat.

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It would not be impossible to provide a list of additions for each entry in the BJCP style guidelines but if someone were to do that

1. There would be conflicts because, for example, the Belgian Abbey beers are made with water ranging from very soft to very hard. Weizens are brewed all over Germany and Austria with water which is quite diverse.

2. You wouldn't learn anything if someone just laid it out for you

3. Within a given style there can be a fair amount of variation.

4. What suits your palate within a given style may not suit mine.

The guidelines were never intended to replace a cookbook nor to cover every situation. As they make quite clear they represent a starting point. You must tweak the recommendations until you are happy with the result.

If the problem is not understanding what to do with a Weizen, for example, because it is not specifically mentioned in the sticky you might try the following approach. Go to http://www.pbase.com/agamid/image/57446374 and find a city where Weizen is brewed. Munich is an obvious choice but so is Vienna and they probably brew it around Dortmund and Köln too. Identify the style that is in the sticky that is brewed in one of those cities. In this case, most are lager cities (clearly excepting Köln). Start out with the lager profile. You should also research the beer you are brewing. Though many of the AHA monographs are short on water information (in Warner's Weizen for example it isn't even mentioned). A great source is Ray Daniels "Designing Great Beers" (I think it is). And of course you can also garner information by posting questions like "I'm contemplating brewing a Weizen. How do you all treat your water for this style?" to forums like this one.
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