Mash: Okay to add ONLY Sodium Bicarbonate to Distilled?

Fri Apr 09, 2010 7:03 pm

Something I've always wondered that would help me with mashes for very dark beers:

Is it okay for me to add nothing but Baking Soda (Sodium Bicarbonate) to the mash to raise the mash pH in a very dark beer?

Does the mash actually need Calcium, or can I add my Calcium Sulfate, Calcium Chloride, etc. after the mash and in the boil kettle?

I guess the base question is: Does the mash need any specific minerals, or just a specific pH?

Example:
Strike Water: 4 gallons
Total Grist Weight: 10.5 lbs
Estimated SRM: 41.6
Roasted Mat % of Specialty Grains: 43%

To get a pH of 5.3, I'd need a Residual Alkalinity of 295+. To get there with just Sodium Bicarbonate in the mash, I can add 7.4g of Baking Soda.

However, I also need at least 50 ppm Calcium. And, I want 100 ppm Chloride and 50 ppm Sulfate. To get all of that and still maintain a pH of at least 5.3 during the mash, I'd need: 1.94g Epsom, 3.15g Calcium Chloride, 7.58g Baking Soda, 3.03g Undissolved Chalk.

If I'm lucky and all I actually care about during the mash is pH and not the actual mineral content, then I can get away with: 7.4g Baking Soda in the mash; 1.94g Epsom, 3.15g Calcium Chloride in the boil kettle. Those numbers are calculated for 4 gallons rather than 5, but you get the point.
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Re: Mash: Okay to add ONLY Sodium Bicarbonate to Distilled?

Fri Apr 09, 2010 8:32 pm

If I remember correctly the calcium is for the yeast health...so I am guessing as long as you add enough into the boil you may be ok....but I have just gotten into doing water chemistry
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Re: Mash: Okay to add ONLY Sodium Bicarbonate to Distilled?

Sat Apr 10, 2010 4:30 am

Hop wrote:Something I've always wondered that would help me with mashes for very dark beers:

Is it okay for me to add nothing but Baking Soda (Sodium Bicarbonate) to the mash to raise the mash pH in a very dark beer?


A bicarbonate (HCO3-) ion contributes half as much alkalinity as a carbonate (CO3--) ion. Thus 100 mg/L CaCO3 yields 100 mg/L alkalinity as CaCO3 (no surprise there). 100 mg calcium carbonate contains 2 "milliequivalents" of proton absorbing carbonate ion. 100 mg of sodium bicarbonate, OTOH, contains only 1.2 meq proton absorbing bicarbonate ion and thus 100 mg/L sodium bicarbonate increases alkalinity by but 60 mg/L as CaCO3. Thus you need more of it.

Hop wrote:Does the mash actually need Calcium, or can I add my Calcium Sulfate, Calcium Chloride, etc. after the mash and in the boil kettle?

No as is indicated by the fact that some of the worlds finest beers (Bohemian Pilsners, Munich Helles...) are brewed with water that is low to very low in calcium. If you are concerned that mash pH will be too low you certainly do not need it for pH reduction. Calcium has other benefits to enzymes (including those active during mashing), trub formation, yeast metabolism all the way down to scavenging oxalate from the finished beer so calcium is beneficial but it can be added in the kettle as the chloride. Except in rare circumstances don't want to add it as the carbonate because it will raise pH. The rare circumstances are where you have somehow attained a lower pH than desired.[/quote]


Hop wrote:...Estimated SRM: 41.6...To get a pH of 5.3, I'd need a Residual Alkalinity of 295+.


Unlikely unless you are adding so much roast malt that the beer would be, to my taste anyway, undrinkable. To give you some perspective, I use 10% roast barley in my Irish Stout. My water has an RA of about 60 and the mash goes to pH 5.5. The color of the beer, which really has very little to do with this, comes out to between 60 and 80 SRM. In laboratory experiments with distilled water (RA 2.5) and Maris Otter ale malt it required 30 % roast barley to get a pH as low as 5.2.


Hop wrote:However, I also need at least 50 ppm Calcium. And, I want 100 ppm Chloride and 50 ppm Sulfate. To get all of that and still maintain a pH of at least 5.3 during the mash, I'd need: 1.94g Epsom, 3.15g Calcium Chloride, 7.58g Baking Soda, 3.03g Undissolved Chalk.


If you added all that to 5 gal of distilled water you would, with 10-20% roast grains, most likely come up with a pH much higher than desired.

Hop wrote:If I'm lucky and all I actually care about during the mash is pH and not the actual mineral content,


That really is where most of your concern should lie. In some beers the minerals are part of the taste profile and you want to take some care to get them into the right range at least but in most cases it is mash pH that should drive your mineral additions or lack thereof. I don't know what your water is like out of the tap but were I you I would make a test mash with the grist you intend to use and check the pH. It may be fine or, if your water is alkaline it may be higher than you want (in which case you would need to add calcium and/or acid) and it may be too low. In my experience the last is the least likely but it could happen if you use lots of really acid roast malts. In this case you can add some calcium carbonate to the mash until pH falls into the right range. Scale the addition up to full size, mash away and be sure to check pH in the mash tun. Adjust additions in future brews until you are hitting mash pH every time.
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Re: Mash: Okay to add ONLY Sodium Bicarbonate to Distilled?

Sat Apr 10, 2010 5:22 am

Thanks, A.J.

With regard to my water, I use distilled because my local water is extremely variable (in any given day, it can come from one of two, or both, places).

As for this particular recipe, 15% of the grist is made from De-bittered Black, Pale Chocolate, and Carafa Special (Dehusked). Another 15% is made up of Caramunich, Crystal, and Dextrine Malt. This is actually a new variation on my normal recipe because I previously used normal Black, normal Chocolate, and normal Carafa at around 10% of the grist, but I wanted to try to pull even more toasty/roasty/coffee/chocolate flavors without increasing the astringency.

With roasted malts at 10% of the grist (and caramel at 15%) and distilled water, I could dip down below 5.0 according to the strips I was using. Because of this, I've always tried to add baking soda and/or calcium carbonate in the mash to make sure I had both calcium and some buffering power.

I previously would also calculate all of my desired ion concentrations and get those into the mash, which could lead to some annoyances because all of the brew sheets in the world tell me to get my residual alkalinity very high for very dark beers (I find that Brau Kaiser's is actually more comprehensive than Palmer's now with his research on roasted vs. caramel malt effects on pH. Whether either is accurate is still a big question mark).

It sounds like the calcium is, in fact, not important during the mash, which is a nice revelation. That means I can indeed stop calculating my water so painstakingly before the mash, and adjust as necessary based on pH tests instead. Then, I can add the proper ppm of minerals during the boil.

Thank you again for being a fount of knowledge over here.
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Re: Mash: Okay to add ONLY Sodium Bicarbonate to Distilled?

Sat Apr 10, 2010 5:37 am

ajdelange wrote:A bicarbonate (HCO3-) ion contributes half as much alkalinity as a carbonate (CO3--) ion. Thus 100 mg/L CaCO3 yields 100 mg/L alkalinity as CaCO3 (no surprise there). 100 mg calcium carbonate contains 2 "milliequivalents" of proton absorbing carbonate ion. 100 mg of sodium bicarbonate, OTOH, contains only 1.2 meq proton absorbing bicarbonate ion and thus 100 mg/L sodium bicarbonate increases alkalinity by but 60 mg/L as CaCO3. Thus you need more of it.

Tangential question from this: Isn't this only true for chalk that has been dissolved with CO2, rather than undissolved chalk added directly to the mash?

According to my calculations here, 100 ppm of dissolved chalk will contribute 101.6 mg/L alkalinity as CaCO3 and 100 ppm of undissolved chalk will contribute 50.8 mg/L alkalinity as CaCO3.
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Re: Mash: Okay to add ONLY Sodium Bicarbonate to Distilled?

Sat Apr 10, 2010 7:18 am

That is a factor. Undissolved chalk (or sodium carbonate or magnesium carbonate....) contributes the most alkalinity. Once dissolved it takes one proton (hydrogen ion) to convert the carbonate ion to bicarbonate and another to convert the bicarbonate to carbon dioxide (alkalinity is approximately the amount of acid needed to convert any carbonate or bicarbonate to CO2). With powdered sodium bicarbonate ony one proton is needed. In a solution the alkalinity depends on the total amount (carbonic, bicaronate and carbonate) of carbonyl in the solution and the pH.

With distilled water I'd start with 2 grams of CaCl2.2H2O per 5 gal. treated. This would give you 30 mg/L Ca++ and 53 mg/L Cl- which seems a reasonable place to start. If you want some sulfate for hops character you can add some gypsum.

I think it's very difficult to predict mash pH from water chemistry without knowing the titratable acidity and buffering capacity of the malts being used. This needs to be determined by experiment. Or you can do a test mash which is equivalent but does not require calculating either titratable acidity or buffering capacity - just observing the resulting pH.

Unfortunately, many brewers seem to be lead astray by test strips. Kai's experiments found that they seem to read 0.3 pH low in brewing applications. If this is indeed correct then your reading near 5 would indicate pH 5.3 and I would expect a 10% roast malt grist to fall around 5.4 - 5.5 with DI water. The good news is that reasonably priced, quite accurate pH meters are now available and sold by HB suppliers. The bad news is that you can still be lead astray (there is some learning curve) and that the meter will have to be replaced (or at least the elctrode, which is 90% of the cost of the things, will) every 2 years assuming you treat it properly - sooner than that if you don't.
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Re: Mash: Okay to add ONLY Sodium Bicarbonate to Distilled?

Sat Apr 17, 2010 12:17 am

It sounds like the calcium is, in fact, not important during the mash, which is a nice revelation. That means I can indeed stop calculating my water so painstakingly before the mash, and adjust as necessary based on pH tests instead. Then, I can add the proper ppm of minerals during the boil.


You may have embraced that concept a little to enthusiastically. Sure, you can mash nicely in low calcium water, as anyone who has brewed in Melbourne can attest (our water makes Pilsen water look hard as rocks) - but that doesn't mean it isn't nicer for the mash to actually have a little of the stuff. Enzymes like a bit of it.

So for sure you can fret a little less about the profile of your water and just concentrate on getting your pH right - just remember to take all of AJ's wisdom to heart and use CaC03 to tweak up your Ph (if you actually need to) and leave the sodium bi-carb in the cupboard.

And you certainly need to add Calcium to the boil if there isn't much of it about - AJ touched on all the good things it does - just be aware that some homebrewing texts will quote you the desired ppm for ions on the assumption that you will be adding the salts to the mash ... where-upon a goodly half or so of them could be lost during the mash boil process. So they whack enough in at the start to ensure the right amount at the end of the boil.... If you are adding during the boil, you will lose significantly less. So you just need to be aware of the issue and determine whether you are working from a figure that is talking about ppm in the beer, or the fermenter, or the strike water before you settle on an amount to add.

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Re: Mash: Okay to add ONLY Sodium Bicarbonate to Distilled?

Sat Apr 17, 2010 12:12 pm

Thanks. Yeah, I'm uncomfortable not having calcium in the mash myself, and ended up figuring out a way to go about getting the best of both worlds. In short, in my next sweet stout, I'll steep the roasted games separately from the mash. I posted a long summary on my site and on the forums here: viewtopic.php?f=2&t=20115
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