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Old 08-08-2012, 12:20 PM   #11
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Okay, this will probably only muddy the waters. I am planning water adjustments in Bru'n Water for a Marzen I plan for this weekend.
Using the amber malty profile it suggests an RA of 45.
After some Gypsum and Calcium Chloride additions my estimated mash PH is 5.3 and the finished water profile shows an RA of -18.
If I add a little baking soda I get the RA to the 45 and my estimated mash PH is 5.6.
Heres the question, do I or don't I care what the RA is?
No! RA is not a criterion for beer production. Only mash pH matters.

I uploaded a new version of Bru'n Water last week with revisions to the color-based water profiles that are stock in the program. Those profiles were created based on an assumption of creating a beer at the upper end of the color range. That produced estimates for a higher starting guess for the bicarbonate content for each profile. The revised profiles assume the production of a beer at the lower end of the color range and the starting guess for the bicarbonate content is much lower now. Correspondingly, the RA for those profiles is now lower too.

Since a lower than optimal mash pH range tends to make better beer than a higher than optimal mash pH range, this revision is less likely to lead a brewer astray. More importantly, a brewer should remember that their mash pH estimate is the primary goal and RA is not. Adjust the bicarbonate content of the mashing water to produce an acceptable mash pH.
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Old 08-08-2012, 12:23 PM   #12
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No! RA is not a criterion for beer production. Only mash pH matters.

I uploaded a new version of Bru'n Water last week with revisions to the color-based water profiles that are stock in the program. Those profiles were created based on an assumption of creating a beer at the upper end of the color range. That produced estimates for a higher starting guess for the bicarbonate content for each profile. The revised profiles assume the production of a beer at the lower end of the color range and the starting guess for the bicarbonate content is much lower now. Correspondingly, the RA for those profiles is now lower too.

Since a lower than optimal mash pH range tends to make better beer than a higher than optimal mash pH range, this revision is less likely to lead a brewer astray. More importantly, a brewer should remember that their mash pH estimate is the primary goal and RA is not. Adjust the bicarbonate content of the mashing water to produce an acceptable mash pH.
Off topic here, Martin, but does the update include an option for pounds/ounces/gallons instead of liters/kilograms? My math skills stink, and I'm perpetually stuck in the US measurements.

One thing I've been happy with is concentrating on mash pH. Once in a while, I'm a little on the low end in a new batch, but overall I have been ignoring the RA and concentrating on a pH of 5.3-5.5 with good results.
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Old 08-08-2012, 02:42 PM   #13
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Off topic here, Martin, but does the update include an option for pounds/ounces/gallons instead of liters/kilograms? My math skills stink, and I'm perpetually stuck in the US measurements.

One thing I've been happy with is concentrating on mash pH. Once in a while, I'm a little on the low end in a new batch, but overall I have been ignoring the RA and concentrating on a pH of 5.3-5.5 with good results.
What part of the spreadsheet are you talking about? Are you sure you didn't download the SI version as opposed to the US version?
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Old 08-08-2012, 04:38 PM   #14
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What part of the spreadsheet are you talking about? Are you sure you didn't download the SI version as opposed to the US version?
I didn't think so- but anything is possible! I'm going to update anyway, so that should fix whatever I did.

Thanks!
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Old 08-09-2012, 04:03 AM   #15
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No! RA is not a criterion for beer production. Only mash pH matters.
Thanks Martin. I just used version 1.13 to plan this weeks Marzen brew.
How do we reconcile the theory that RA is not important with Plamers video above? He suggests RA makes a difference in the complexity of the flavors.
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Old 08-09-2012, 01:02 PM   #16
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RA is an important factor, but it is not more important than mash pH.

I appreciate John's sentiment regarding RA and getting the mash water RA in the proper range is important for getting the mash pH in range. But I have a disagreement that the finished beer color can be used to decide what that RA value should be. The grist composition can play havoc with the mash pH and that can throw that color-based RA correlation out of kilter. So, mash pH is actually the criterion that is more important to control.

Regarding complexity and RA. That can be a problem too. Look at 2 water profiles (Pilsen and Burton) that have nearly identical RA values (around zero) and it should be no problem to see that these waters would impart totally different character to beer. So, that argument can be subverted.

On the other hand, I have experienced beers that were brewed with RA levels that did not produce appropriate mash and kettle pH. Their 'complexity' (taste quality) was lacking in comparison to beers brewed with appropriate water. At a general level, RA is important. It's just that it is not THE thing that the brewer should use to assess if their water is suitable.

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Old 08-09-2012, 01:22 PM   #17
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John is still a little hung up on RA but I think he is coming around. I'm actually starting to feel a little vindicated in all this.

If you desperately need something to hang onto in this turbulent sea of brewing water chemisty, and we do, you are likely to grasp at anything that floats. RA/SRM and Cl/SO4 are a couple of things that have been tried. What happens is that a correlation is observed. In particular here presumably John brewed a couple of beers and found a relationship between something he likes and RA. Let's say I brew a bunch of stouts and adjust the RA's and submit the beers to a competition and receive a set of scores like those shown in this picture:
http://www.homebrewtalk.com/photo/fa...ion-56032.html

You have to click on it to see the details. In any event these data show that clearly increasing RA increases one's score. I did not brew these beers this is synthetic data for illustration purposes. The scores and RA are, in this picture, completely independent random variables. There is no correlation between them (even though Pearson's r for this set is fairly high). Were I to take enough data from this model the lack of correlation would become apparent. The point is that random chance can make things appear to be correlated when in fact they are not and I suspect that may be what is responsible for John's comment (though to be honest I haven't listened to the talk).

Another thing that bites people is confusion of correlation with causation. It was observed, for example, that when the US lowered its speed limit to 55 during a fuel crisis highway deaths went down substantially and it was assumed, quite reasonably, that lowering the speed limit lead to safer driving. But traffic deaths also went down in Germany where they didn't lower their speed limits. Lower deaths and lower speed were correlated but the causative factor was that there were fewer people driving because fuel was in short supply. In the brewing context if one adds more and more calcium chloride to his beers they are likely to taste better (up to a point) because of the chloride's sweetening and smoothing effects. But RA is also going down as calcium chloride additions are being increased. So RA and beer quality are correlated but it is in fact the increased chloride that is responsible. Again I'm not suggesting that this is the actual explanation for John's comments but just pointing out there are several ways in which he could have been lead to his conclusion.

Then there is our ancient foe cognitive bias. Once you (or anyone) decides on something he tends to clearly see and remember anything that supports his belief in this something and not notice nor long remember anything that contradicts it. This has not only ruined a lot of beer but destroyed a lot of investors' portfolios and caused plenty of misery in general.

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Old 11-13-2012, 04:33 PM   #18
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I'm going to resurrect this thread because I just learned something that cleared the whole thing up for me, so I thought I'd post here in case the same thing can occur for others.

I was reading a thread on water pH on the AHA website, got confused, so asked this question:
"Oh my. There is so much I don't know. This statement at my current level of understanding makes no sense. Alkalinity is just one side of the sliding scale we call pH, isn't it? Alkalinity is just the opposite of acidic on this scale isnt it?"

To which I got a couple of great responses: first from NATEO:
"Think of alkalinity as the water's resistance to acidification. Think of the pH spectrum as acidic to basic. Alkalinity represents the water's ability to neutralize an acid, and has no direct impact on pH.

My water, for instance, has insanely high alkalinity but typically has a pH of 7.4. Since it has a lot of alkalinity, it takes a lot of acid to move the pH downward, as the alkalinity is "consumed" by the acid. Once the acid eats all the alkalinity, there is nothing in the water to stop the acid, and so any more acid drops the pH by a lot."


Then MABRUNGARD added to this by saying:
"There is a definition of alkalinity that presents it as the opposite of acidity. Unfortunately, that is not the definition in use here. Alkalinity is a measure of the buffering capacity of the liquid or resistance to acidification as Nate mentions. In typical drinking water, alkalinity is the measure of carbonate and bicarbonate ions in the water. They are the ions primarily responsible for alkalinity. Therefore, alkalinity is not equivalent to pH. They can be quite different."

That obviously changes my whole understanding of what Residual Alkalinity means. I love epiphanies like this!

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Old 11-13-2012, 04:41 PM   #19
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To continue, I was getting frustrated chasing my tail trying to get the RA to be anywhere in the ballpark of where it was supposed to be. I finally gave up and just followed MABRUNGARD's advice and just attended to mash pH.

The big part of the problem was that I use RO water, in which there is presumably NO RA - no buffering capacity. So to get the RA where "it should be" meant that I had to raise the pH to where it shouldn't be.

I am certain I still have something incorrect in my mental map of all this, but I'm pretty certain a big foundation stone was just put in place.

Steve

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Old 11-13-2012, 05:22 PM   #20
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I'm not sure about that. I've never found RA to be a good indicator. It was always frustrating to try and get the RA where it needed to be with my water. Way too much alkalinity.

I just focus on pH and try to get the various minerals to their recommended ranges for yeast health and flavor. The chloride:sulfate ratio helps me choose which minerals to add to raise or lower pH and target a balanced flavor. I'm not convinced I've found that the chloride:sulfate ratio is all that important if you get a mix of minerals that promote yeast health and target a good pH.

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