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-   -   Does RA really matter at all? (http://www.homebrewtalk.com/f128/does-ra-really-matter-all-349338/)

disney7 08-22-2012 09:34 PM

Does RA really matter at all?
 
I'm new to water adjustments and have read the primer and it has worked well in my brews so far. However, I'm trying to understand more about water adjustments.

Palmer seems to advocate that Residual Alkalinity (RA) makes a big difference in your results and should be adjusted for in different beer styles, particularly light colored hoppy beers and dark malty beers.

My water is very soft, quite similar to a Pilsen water profile. Here is my local water profile:

pH 7.8
Total Dissolved Solids (TDS) Est, ppm 59
Electrical Conductivity, mmho/cm 0.10
Cations / Anions, me/L 0.7 / 0.7

Sodium, Na 5
Potassium, K < 1
Calcium, Ca 7
Magnesium, Mg 2
Total Hardness, CaCO3 26
Nitrate, NO3-N < 0.1 (SAFE)
Sulfate, SO4-S < 1
Chloride, Cl 8
Carbonate, CO3 < 1
Bicarbonate, HCO3 28
Total Alkalinity, CaCO3 23
Total Phosphorus, P 0.94
Total Iron, Fe < 0.01

If I add enough slaked lime, baking soda, or chalk to get my RA up into the suggested ranges for a dark beer, it jacks (according to EZ Water calc, which I've found to be fairly accurate when I test with a meter) my pH up and requires acid addition to get it back down.... which lowers my RA.

Palmer's spreadsheet doesn't seem to worry about mash pH at all.

So, I can't raise my RA without dealing with a mash pH that is too high.

Should I forget about RA and just worry about mash pH and the Chloride/Sulfate ratio?

Thanks for any pointers

ajdelange 08-22-2012 11:53 PM

Quote:

Originally Posted by disney7 (Post 4353045)
So, I can't raise my RA without dealing with a mash pH that is too high.

Doesn't that answer your question?

Quote:

Originally Posted by disney7 (Post 4353045)
Should I forget about RA and just worry about mash pH and the Chloride/Sulfate ratio?

Yes, indeed - concentrate on mash pH. Don't let anybody tell you that you need a particular RA for a particular color beer. You need as much acid or alkalinity as are necessary to set the mash pH properly. Usually you will need acid. Sometimes you will need alkali. There are those who will tell you that a dark beer needs alkali because if you don't supply it the beer will taste sharp and thin. If you get pH in the range 5.4 - 5.6 and it tastes sharp and thin to you then you might want to go to higher pH but if it doesn't then don't. pH is like any other variable. You have to learn what gives you beer you like and shoot for that.

Chloride/sulfate ratio is an attempt to compress 2 variables into 1. Don't fall for this one either. A beer brewed with 1 mg/L SO4 and 1 mg/L chloride will be very different from one brewed with 150 mg/L of each even though the ratio is the same. You cannot 'fix' a beer that isn't 'malt forward' enough which contains 75 mg/L SO4 by adding 215 mg/L chloride. You must learn the effects of sulfate and the effects of chloride and adjust each for the best, by whatever criterion of optimality you choose, beer.
[/QUOTE]

JLem 08-23-2012 12:09 AM

The point of RA is so that your mash pH is in the proper range. The RA itself doesn't really matter. You need a higher RA for darker beers because the darker grains will lower the pH more than lighter grains. But in the end it is the mash pH that matters.

FWIW I am of the opinion that too high a mash pH is a much, much bigger problem than too low a pH. If the pH is too high, you'll extract a lot of tannins and have an unpleasant astringency in the final beer. This is why I tend to worry about my lighter beers much more than my darker beers. I'd be hesitant to add a lot of salts to the mash to raise the RA/pH for a dark beer. I doubt you'll need much if any to get a proper mash pH. RAs above about 200 are pretty much pointless anyway.

Do what you need to do to dial in your mash pH, but if you have to, err on the low side. The thought of adding slaked lime to my mash would give me pause.

cyberwollf 08-23-2012 12:14 AM

You can always mash only your light grains without worrying about RA then add the dark grains at vorlouf

ajdelange 08-23-2012 12:59 AM

Quote:

Originally Posted by JLem (Post 4353391)
The point of RA is so that your mash pH is in the proper range.

RA was conceived for comparison of brewing water through characterization of probable mash pH in base malt only lager beers. For comparing waters it is valuable. When people try to make it do more than that is where we get into trouble.



Quote:

Originally Posted by JLem (Post 4353391)
FWIW I am of the opinion that too high a mash pH is a much, much bigger problem than too low a pH. If the pH is too high, you'll extract a lot of tannins and have an unpleasant astringency in the final beer.

I agree with this sentiment (except that I'd describe the flavors of beer brewed at too high a pH as dull, lifeless) but then somehow I have never managed to achieve too low a pH despite people telling me that I must be doing so because I don't enhance the alkalinity (RA) of my water when brewing stout.

mabrungard 08-23-2012 01:01 AM

RA only matters because it has a strong influence on mash pH. But as mentioned above, pH is the target in brewing, not RA.

Wynne-R 08-23-2012 03:28 PM

AJ, Iím sure youíre right about the mash pH. However, it is important to point out that sparging with that water will extract tannins.

My alkalinity is 100-125 and I brew mainly pales. When I switched to RO sparge, the difference was HUGE. I went 50/50 on the mash and the difference was much less pronounced.

Since I got a pH meter, I have been adding calcium chloride and lactic acid. I havenít bottled that one yet.

ajdelange 08-23-2012 04:19 PM

Quote:

Originally Posted by Wynne-R (Post 4354827)
AJ, Iím sure youíre right about the mash pH. However, it is important to point out that sparging with that water will extract tannins.

You are absolutely right to be concerned about this but the water in question has an alkalinity of 23 and it would be unlikely that tannins would be extracted if the brewer stopped collecting at 3 -4 įP.

Quote:

Originally Posted by Wynne-R (Post 4354827)
My alkalinity is 100-125 and I brew mainly pales.

Now that's a different story. Were you to sparge with water this alkaline you would certainly run into tannin extraction much earlier.

But again, it is the pH which is the most important thing. You could sparge with your untreated water if you monitored the runoff pH and terminated collection when it reached 6. You might not like the amount of extract you were leaving behind and of course the solutions are dilution or acid treatment (if you are willing to live with the acid cation).

The OP, even with his low alkalinity water, should check runoff pH to determine where he should stop collecting.

Wynne-R 08-23-2012 04:32 PM

Oops! My mistake, I thought it was 123.

Anyway, thanks for explaining it so much better than I did. Iím sure your advice will be useful for brewers doing pales with 100+ alkalinity.


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