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Old 04-11-2011, 10:13 PM   #1
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Default RA or Mash pH? Which is most important to get in a certain range

I am trying to build my water for a Black IPA. It's going to be very high in IBU (about 100). Grain bill will be fairly straightforward (15.5# of 2-row, 1# of Crystal 60, 1# of Carafa III). SRM estimate is 38.

Here is my water profile
Ca 56
Mg 26
Na 23
Cl 10
So4 9 (adjusted because it is SO4-s)
HCO3 302

I have been using the spreadsheet put together by -TH- to determine how to treat my water. I'll be using 6 gallons of mash water with a dilution of 2:1 distilled:my tap water (67% for purposes of the spreadsheet). I do this primarily to cut the alkalinity of my water and reduce my RA.

The precision on my pH meter is only .1, however, I have noticed that my pH readings are generally pretty close to what the sheet estimates.

With this dilution and no other mineral additions, the spreadsheet anticipates a mash pH of 5.03. However, it still puts my RA at 63 and my Ca, SO4 and Mg are all below the recommended ranges for brewing.

If I add Gypsum, CaCl, and perhaps a tiny amount of Epsom salt in order to bring my RA down and move my minerals into acceptable ranges, that works, but it further drives down my already low mash pH.

I have also tried looking at a smaller dilution% of distilled, but while that helps raise the estimated pH a bit, I have to add a large amount of minerals to bring my RA in line. This in turn starts to throw my ppm measurements on the various minerals out of whack (and again starts bringing the pH fairly low).

I seem to have this thing on a scale that I can't balance. I tip too far one way and it throws the other out of whack. I can either get mash pH into the 5.2-5.5 range or bring RA below 50. But I am having trouble doing both. I have thought about one of the pH raising mineral additions and it only serves to drag RA with it.

At this point, my only other option is to reduce the amount of either crystal or carafa and bring the SRM down and the pH up a bit.

Any ideas?

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Old 04-11-2011, 10:22 PM   #2
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I just tried the last part. I took the crystal and carafa to 3/4# each and replaced that with a half pound of 2 row. It changes the SRM to 32. Plugged into the spreadsheet with the 67% dilution and an addition of 4 g gypsum, 2 g cacl and 1 g epsom yields a mash pH of 5.08 (still a touch low) with an RA of 15. Better. What do you think?

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Old 04-12-2011, 12:01 AM   #3
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It is possible to adjust pH without significantly altering your ion profile. I've always done this using analytical grade (i.e. food grade) potassium hydroxide, or if not available, analytical grade sodium hydroxide. Adjust your waters ionic makeup, then adjust the pH to the desired pH using KOH/NaOH. Both KOH and NaOH are highly caustic, so handle with care.

I work in a lab, so I have no idea what the availability of these products are in the real world. None-the-less, you cannot be the first brewer whose had this issue, and I'd be highly doubtful if a strong base of some sort was not available for the purpose of adjusting pH.

Bryan

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Old 04-12-2011, 01:11 AM   #4
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Lab grade KOH and NaOH are easy to get, check out essential depot.

I use lactic acid as sauermalz to adjust pH down and chalk in the past to adjust it up. I intend to use KOH in the future but since making that decisions I am through a dozen batches with no need to raise pH.

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Old 04-12-2011, 01:16 AM   #5
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The ONLY thing that matters is mash pH. RA provides a rough guess of what the mash pH will do with a straight pale malt grist. You cannot rely on RA to predict your mash pH since some grains have differing levels of acidity and the resulting mash pH can be all over the place eventhough the beer color says it should be OK.

Forget about RA and aim for a proper mash pH and your beer will be better. The lowest mash pH you should think about aiming for is 5.2 and I suggest that even that is too low. The optimum mash pH range is 5.3 to 5.5.

You can learn more about mashing water chemistry and how to properly adjust it by downloading and reading Bru'n Water at the link in my signature line.

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Old 04-15-2011, 08:58 PM   #6
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Quote:
Originally Posted by mabrungard View Post
The ONLY thing that matters is mash pH. RA provides a rough guess of what the mash pH will do with a straight pale malt grist. You cannot rely on RA to predict your mash pH since some grains have differing levels of acidity and the resulting mash pH can be all over the place eventhough the beer color says it should be OK.

Forget about RA and aim for a proper mash pH and your beer will be better. The lowest mash pH you should think about aiming for is 5.2 and I suggest that even that is too low. The optimum mash pH range is 5.3 to 5.5.

You can learn more about mashing water chemistry and how to properly adjust it by downloading and reading Bru'n Water at the link in my signature line.
Yep. I think this RA nonsense came from a BYO article years back?
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Old 04-15-2011, 09:47 PM   #7
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Its not nonsense, its just that it can't be well correlated to beer color as was attempted in the past. RA is still very valid, it just isn't a good predictor for mash pH under some conditions.

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Old 04-16-2011, 02:57 AM   #8
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RA is excellent for its intended purpose: comparing water supplies. It has been turned into nonsense by some in the HB community who have assayed to hang the entire design of mash/beer on it. It wasn't intended for that and it isn't very good for that.

One of the most interesting aspects of it is that its oft cited correlation with mash pH is not what Kolbach described. He spoke of a correlation with wort knockout pH. Now that, of course, correlates with mash pH and so there is a correlation between mash pH and RA but it isn't probably very tight (low Pearson's r).

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Old 04-16-2011, 01:15 PM   #9
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I have been working to get both the RA in line and the mash pH in the 5.2-5.4 range for a couple of reasons:

1. In many of my discussions with ajdelange here, my RA was at issue, primarily because the water I begin with is so highly alkaline. Per the report from ward labs, my bicarbonate comes in at 302 with a total alkalinity of 247.

2. Although it was brought into question a couple of posts above this, I did recently read an article in BYO (I can pull the exact issue when I get back to my house if needed) where the writer says that for basic brewing water, you should try to bring your RA down to 50 or lower for most styles.

Much of the confusion I have right now stems from using the spreadsheet built by -TH- any available in this forum. When I add the grains, my base water and enter the predicted SRM for this beer in his sheet, I get a predicted mash pH of 5.27, but an RA of 192. That's with no mineral additions and no dilution with RO water

If I add minerals or dilute my water to bring the RA down, it pushes my mash pH below 5.2.

I once asked aj what I would expect with a high RA; how I would know that any flavor contributions to a beer were from alkaline water. He told me to dissolve a small amount of baking soda in a glass of water and taste it and see how I liked the flavor. I was not happy with the results of that test.

So I find myself back at my original question, which is going to be the most important for this beer? The recipe as it stands alone with my house water will be in the right pH range (just over 5.2) with an RA of nearly 200.

If I dilute my mash water with 50% distilled and add 3g each of Gypsum and CaCl, the sheet shows that I should expect an RA of 49, but that my expected mash pH would be 5.12.

Not to muddle the argument any further, but I am running into the same problem with a stout recipe I have on deck after this Black IPA. I can either get the RA in range and the mash pH lower than 5.2, or I can get the mash pH in the 5.2-5.4 range and the RA will be over 150

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Old 04-16-2011, 02:54 PM   #10
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The advice to keep RA below 50 in most cases is good advice. It is seldom that alkalinity brings anything to the party. The only exception to this would be where a lot of dark malt is being used and pH is at or below the low end of acceptable. It has been my experience that one can make some very dark beers with water with an RA of 50 or less without going too low but that assumes that the dark/roast malts are in what are, to my taste, reasonable proportion. If you are using dark malts beyond this point then there is the possibility of low mash pH. You usually want to compensate for this by adding some alkali (chalk, lime) to the mash as opposed to trying to increase the RA of the water.

Under no circumstances should you accept an indication that RA needs to be set at a given level based or beer color nor should you pay any attention to a change in SRM based on a mineral addition or dilution that changes RA. The connection between beer color and SRM is tenuous.

The best thing for you to do here, IMO, is prepare RO/DI water with 1/2 - 1 tsp calcium chloride per 5 gal. This will give you very low alkalinity and negative RA. Swap gypsum for half the calcium chloride if you want assertive hops (which it appears you do). Mash in and check mash pH. If it is too low, add some chalk or picking lime. There is a good chance that mash pH will not be too low. It really depends on the base malt and the particular colored malts.

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