SRM to RA analysis

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Kaiser

Kaiser

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This is in continuation of an off-topic discussion that was started in this tread (https://www.homebrewtalk.com/f128/side-side-water-modification-test-139577). The last post is here: https://www.homebrewtalk.com/f128/side-side-water-modification-test-139577/#post1718157

SpanishCastleAle said:
If you don't have alkaline enough water for dark brews, would there be a benefit to adding the dark roasted grains in Stouts/Porters toward the end of the mash?
Click to expand...

I’m not sure if that will always work that well. The roasted grains will pull down your wort pH and you may end up with a boil wort pH that is too low for good protein coagulation and hop utilization. I believe that, if they are necessary, the salts are needed one way or the other.

Kai
 
Thanks Kai. I'm making an Oatmeal Stout very soon (hopefully Sunday) so I'll try it again and be sure to measure the pH after the dark grain addition. If it goes too low I'll add some chalk (or baking soda?).
 
One quick question about measureing pH of dark beers. I have the paper pH strips. Every time I measure a dark beer, it just stains the strip dark brown. Is there something I'm missing, or is a meter a must?
 
Edcculus said:
One quick question about measureing pH of dark beers. I have the paper pH strips. Every time I measure a dark beer, it just stains the strip dark brown. Is there something I'm missing, or is a meter a must?
Click to expand...

If you are using the colorpHast strips try blotting them with a paper towel.

Kai
 
I am brewing a big RIS tomorrow (~1.100 & 2# black barley) via partigyle... I was hoping to get the RA up to ~200, I am concerned with your comments about undissolved chalk; how exactly do I dissolve it? I thought the mash ph would help to dissolve it during the mash, is that incorrect?

edit:
nevermind, I found it

https://www.homebrewtalk.com/f36/undissolved-vs-dissolved-chalk-148581/
 
nealf said:
I am brewing a big RIS tomorrow (~1.100 & 2# black barley) via partigyle... I was hoping to get the RA up to ~200, I am concerned with your comments about undissolved chalk; how exactly do I dissolve it? I thought the mash ph would help to dissolve it during the mash, is that incorrect?
Click to expand...

This is an odd thing that I found when I evaluated how undissolved chalk reacts in the mash to raise mash pH. I have no explanation for that but once you add more than 300-400 ppm (0.3 – 0.4 g/l or 1.2-1.6 g/gal) it won’t raise the pH anymore. In addition to that, the mash pH rise that I could get from chalk was only about 0.2 pH units above the distilled water mash pH of the tested grists. This lead me to the comments about dissolved chalk which. A few brewers actually reported something similar where they kept adding chalk but the pH was not moving.

As a result I started advocating using more baking soda until the sodium levels start to become a concern. I think as long as you stay below 50 ppm Na+ you should be fine. Baking soda didn’t show the pH raising limit that I saw with chalk.

The same goes for dissolved chalk. But here you have to keep in mind that most water spread sheets out there are not able to correctly account for dissolved chalk. When chalk is dissolved it has twice the alkalinity power of undissolved chalk. My spreadsheet (http://braukaiser.com/documents/water_calc_v15.xls) has been updated to include support for dissolved chalk and will also give you the CO2 pressure needed to dissolve it if you enter the volume of water you are going to dissolve it in.

How much crystal vs. roasted malts are you using in the RIS. If you are using mostly roasted specialty malts I’m inclined to say that you may not need a RA (residual alkalinity) of 200 ppm.

Over the weekend I want to take some pictures and write a tutorial on practical ways of dissolving chalk in the brewing water. It’s not that complicated, but seeing pictures helps.

Kai
 
Estimated Color: 56.4 SRM

26.00 lb Pale Malt (2 Row) US (2.0 SRM) Grain 76.4 %
2.75 lb Black Barley (Stout) (500.0 SRM) Grain 8.1 %
1.90 lb Special B Malt (120.0 SRM) Grain 5.6 %
0.85 lb Caramunich Malt (56.0 SRM) Grain 2.5 %
0.85 lb Chocolate Malt (350.0 SRM) Grain 2.5 %
0.85 lb Pale Chocolate (200.0 SRM) Grain 2.5 %
0.85 lb Victory Malt (25.0 SRM) Grain 2.5 %

Total Grain Weight: 34.05 lb
----------------------------
Name Description Step Temp Step Time
Mash In Add 42.56 qt of water at 165.9 F 154.0 F 60 min
Click to expand...

I am only putting 2# of the Black Barley into the primary mash, I was planning to add the .75# after the first runnings were drained. I am not sure if "Special B" counts as a crystal malt... if it is not then the crystal malt additions are rather low in the grand scheme of things.

If this looks weird for a RIS, the first 5G of runnings will be the RIS and the second runnings will go into another smaller beer. This probably makes the mash pH more manageable due to the reduced SRM... or maybe it doesn't affect it at all; I have no idea!
 
nealf said:
I am only putting 2# of the Black Barley into the primary mash, I was planning to add the .75# after the first runnings were drained. I am not sure if "Special B" counts as a crystal malt... if it is not then the crystal malt additions are rather low in the grand scheme of things.

If this looks weird for a RIS, the first 5G of runnings will be the RIS and the second runnings will go into another smaller beer. This probably makes the mash pH more manageable due to the reduced SRM... or maybe it doesn't affect it at all; I have no idea!
Click to expand...


Special B is indeed a Crystal malt. Usually in the 115-130 range.

With the many subsequent runnings involved in partigyle brewing I would think you are going to get increasing pH with the more water you run through, since the mash will be losing it's buffering ability if you will against the extremely high volume of water.
 
I've had several conversations with Mike McDole on this topic.

I was brewing his Brown Ale and he gave me his water profile:

Me - "I got my water pretty close. I just can't get my Sodium down to your target. Yours is 17 and mine's 58 ppm. Are you using straight RO water or dilluting?:

Mike - "RO"

Me - " how in the world do you keep your sodium down? I've got the NaHCO3 jacked up to bring up my RA, which is where I'm getting all my Sodium from. My RA is 129. I'm not using any Chalk to raise the RA because my Calcium's so high from the Gypsum to reach the 350 ppm you have. Is your RA lower than mine?"

Mike-"That's the difference, I don't adjust the carbonates. My only Na addition is from NaCl. So yes, my RA is probably much lower than yours."

Me - "So no matter your SRM you don't adjust the carbonates?"

Mike - "I don't adjust the carbonates but that in no way says I shouldn't. I always check the Ph of the mash for dark beers, including the Janet's Brown, and it's always 5.1 or 5.2. Your results may vary."


No matter how much I wanted to believe him, I couldn't adjust the salts to bring my RA down below the suggested SRM of the beer. I did bring my sodium down.

So how important is it?
 
chefchris said:
I've had several conversations with Mike McDole on this topic.

I was brewing his Brown Ale and he gave me his water profile:

Me - "I got my water pretty close. I just can't get my Sodium down to your target. Yours is 17 and mine's 58 ppm. Are you using straight RO water or dilluting?:

Mike - "RO"

Me - " how in the world do you keep your sodium down? I've got the NaHCO3 jacked up to bring up my RA, which is where I'm getting all my Sodium from. My RA is 129. I'm not using any Chalk to raise the RA because my Calcium's so high from the Gypsum to reach the 350 ppm you have. Is your RA lower than mine?"

Mike-"That's the difference, I don't adjust the carbonates. My only Na addition is from NaCl. So yes, my RA is probably much lower than yours."

Me - "So no matter your SRM you don't adjust the carbonates?"

Mike - "I don't adjust the carbonates but that in no way says I shouldn't. I always check the Ph of the mash for dark beers, including the Janet's Brown, and it's always 5.1 or 5.2. Your results may vary."


No matter how much I wanted to believe him, I couldn't adjust the salts to bring my RA down below the suggested SRM of the beer. I did bring my sodium down.

So how important is it?
Click to expand...

I've been reading some of A.J. Delange's posts and lately he's been telling brewers to just adjust water for your sulfate/chloride ratio and worry about mash ph when you're actually measuring it. If it needs to go down, then add lactic acid/sauermalz. If it need to go up, then add chalk. From what I understand, the relationship between SRM and mash ph is not as black and white as popularly perceived. IIRC, even some of Kai's experiments have shown that crystal and higher kilned base malts(Munich and such) pull down ph more than roasted grains do. So I would believe Tasty.
 
I’m familiar with A.J.’s approach of adjusting pH after testing it. But I do think that the relation between grist composition and water chemistry are predictable enough that one can design water to get close enough to the desired mash pH. The target for mash pH is fairly large and it takes quite significant water or grist changes to be off far enough to warrant a fix. I like the fact that I can predict my mash pH when I design the recipe and don’t have to mess with pH adjustment after dough-in. This is easier for my style of brewing but it may not be easier for other brewers.

As for using water with an RA or close to 0, this will work for more beers than you think. Just look at figure 1 of the article. Most beers had a distilled water mash pH (RA=0) that was either in the preferred range or in the acceptable range. I don’t know how Tasty measures pH, but I consider a room temp mash pH of 5.1 – 5.2 a bit low. Beer quality should be the determining factor but from a technical point of view you may run into problems with the amylases once the pH drops below 5.2. Especially when you use lots of the enzymatically weaker Munich malts.

One of the motivations of this work was to provide an updated formula for the SRM based RA estimation that John Palmer made popular with his spreadsheet. In addition to that it also provides insight into why so many beers can be brewed w/o the need for water adjustment.

Kai
 
Kai.

First time seeing your xls. Want to play with it to see how th result fare against another sheet I have been using. How would I modify the acids section to accomodate 75% phosphoric?
 
Phosphoric acid is a difficult acid to incorporate due to the fact that it reacts with calcium and precipitates some of calcium phosphate salt. But that already happens anyway and not all of the Ca you have in the water ends up in the wort. I would have to experiment with phosphoric acid to see if I can simply accommodate it like any other acid.

But there is an unintended consequence with phosphoric acid that most brewers are not aware of. While it allows you to lower your mash pH, it strengthens the buffer capacity of the wort and as a result the yeast may not be able to lower the beer pH as much as it would be able to do otherwise. This concern is raised in some of the technical books I have where the added phosphates don’t come from phosphoric acids but acid rests or low pH mashes. But it should be the same for phosphoric acid additions. It would be interesting to evaluate the beer pH from 2 beers brewed with the same mash pH but one used phosphoric acid and the other used lactic acid.

Kai
 
Kaiser said:
Phosphoric acid is a difficult acid to incorporate due to the fact that it reacts with calcium and precipitates some of calcium phosphate salt. But that already happens anyway and not all of the Ca you have in the water ends up in the wort. I would have to experiment with phosphoric acid to see if I can simply accommodate it like any other acid.

But there is an unintended consequence with phosphoric acid that most brewers are not aware of. While it allows you to lower your mash pH, it strengthens the buffer capacity of the wort and as a result the yeast may not be able to lower the beer pH as much as it would be able to do otherwise. This concern is raised in some of the technical books I have where the added phosphates don’t come from phosphoric acids but acid rests or low pH mashes. But it should be the same for phosphoric acid additions. It would be interesting to evaluate the beer pH from 2 beers brewed with the same mash pH but one used phosphoric acid and the other used lactic acid.

Kai
Click to expand...

Interesting. I found taht I had to get away from Lactic Acid because on the lighter beer I find myself brewing as of late I was getting a twang in the finished product. Even the wort carried this twang.

Which went away once I started using Phosphoric acid. My, undereducated, guess is that I was using so much LA to get to my pH target that the flavor threshold was surpassed.

Of course, I also treat my sparge water. I was finding that it took sveral ml of Lactic Acid to go from 9.3 to a pH of 7 whereas it takes but a couple ml with the phosphoric.
 

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