Water adjustment for dark beers

[Auger]

I've been getting a specific off-flavor in all of my stouts and porters, which I'm thinking is due to a drop in mash pH from using dark grains. I don't have a pH meter. I don't get this flavor at all in lighter beers, and have good success with bitters and kolsch brewing. I sent in a sample ot ward labs:



Which, as I understand it, roughly corroborates my theory (as much as possible without actually testing mash pH, anyway). My water has pretty low alkalinity and mineral content, good for lighter beers, less so for dark beers with heavier roasted grains.

I'm not trying to replicate any specific water profile, and honestly I'd rather not mess with water additions if at all possible; or as necessary, as little as possible. I'm a little stuck now with how to improve from here. Using Bru'n Water, it looks like I need to add some base to my mash, but not sure how to go about it. It sounds like chalk is going to be too much work to mess around with dissolving under pressure. Here's the water adjustment sheet set up for "black malty" profile:



Am I on the right track, or should I be looking elsewhere?

 

[ajdelange]

The dark beers are tricky because the dark malts have a proton surfeit as opposed to the deficits of the lighter malts. People often think of dark beers as originating with brewers that had high carbonate water to deal with and that's more or less true but what people don't think of is that as soon as that brewer's water hit the HLT a lot of the carbonate dropped out so that the dark malts weren't really furnishing that much acid. If, therefore, you use reasonable amounts (what the original brewers of those beers used) of dark malts you aren't likely to need an alkalinity addition to your mash. As an example of this you could have, with your water, as much a 41% 300L roast barley in a stout before the mash pH dropped below 5.3. That would be a pretty horrible stout. In a more reasonable case with 10% roast barley the mash pH would be about 5.6 and many would argue you actually need acid.

Not fiddling with profiles is good advice but if you do be cautioned that lots of the ones out there (including the Black Malty you are looking at) seem to suffer from a common flaw. They demand more calcium and sodium than you can get from gypsum, table salt and calcium chloride without going over on the chloride and sulfate specs. Most people in fiddling with salt additions would probably never discover this but that profile can be realized exactly by adding
CaCl2.2H2O 189.57
NaCl 21.05
MgCl2.6H2O 146.21
CaSO4.2H20 186.47
MgSO4.7H20 14.67
H2O (DI) Liters 0.00
CaCO3 329.42
NaHCO3 246.38
CO2 0.00
HCl 0.00
Ca(OH)2 0.00
Na2CO3.H2O 0.00
Sodium Lactate 0.00
Potassium Lactate 0.00
Lactic 829.23
Sulfuric 0.00
88% Lactic ml/Gal 0.7819

to a gallon of RO water. Or

Salt/Acid/Base mg/gal Synth
CaCl2.2H2O 165.61
NaCl 29.40
MgCl2.6H2O 88.83
CaSO4.2H20 124.00
MgSO4.7H20 45.84
H2O (DI) Liters 0.00
CaCO3 334.78
NaHCO3 82.22
CO2 0.00
HCl 0.00
Ca(OH)2 0.00
Na2CO3.H2O 0.00
Sodium Lactate 0.00
Potassium Lactate 0.00
Lactic 802.39
Sulfuric 0.00
88% Lactic ml/Gal 0.7566

to your water.

Should a brewer find these exact solutions he will note that alkalinity is required not to cancel malt acidity but to supply calcium and sodium from sources that don't contain sulfate or chloride. These are bad profiles!

 

[Auger]

Not fiddling with profiles is good advice but if you do be cautioned that lots of the ones out there (including the Black Malty you are looking at) seem to suffer from a common flaw. They demand more calcium and sodium than you can get from gypsum, table salt and calcium chloride without going over on the chloride and sulfate specs.

This is kind of what initiated my question - in trying to bump up the Ca and bicarb, it was pushing my sodium way too high unless I use chalk, which isn't going to be a viable option.

I'm wondering if the problem wasn't that the sparge water was too hot. If the water profile looks reasonable for a normal grain bill (no, I'm not brewing stouts with 40% dark roasted grains) then maybe I need to look elsewhere for the problem.

 

[ajdelange]

You should never try to match the bicarb in striving to match a profile.

Be wary of using too much roast malt. People tend to get carried away with it.

 

[mabrungard]

Your results are likely due to overly low mash pH which echos into the kettle wort pH. Most dark styles have improved flavor when the mash and kettle pH are kept above 5.4. Many brewers report a preference for the mash pH to be in the 5.5 to 5.6 range which mellows the roast flavors.

As you mention, chalk is not easy to work with in the brewery since it requires special measures to dissolve. Pickling lime is a decent alternative, but its purity and strength is sometimes in question. The easiest and surest way of adding alkalinity to the mash is via baking soda addition. Its readily available and its purity and strength is reliable. The minor amount of sodium that you add to the mash in achieving a proper pH is diluted when the sparging water (which does have any baking soda) is added to the wort. Sodium at low level, is a desirable flavor ion in dark beers.

 

[ajdelange]

As noted in #2 it is unlikely that he would need to add any alkalinity for a stout or a porter but I will reserve final judgement on that until he tells us his grain bill.

 

[Auger]

This was the recipe for the milk stout I did recently.

Recipe Specifications
--------------------------
Boil Size: 7.74 gal
Post Boil Volume: 6.24 gal
Batch Size (fermenter): 5.50 gal   
Bottling Volume: 5.00 gal
Estimated OG: 1.054 SG
Estimated Color: 34.4 SRM
Estimated IBU: 40.8 IBUs
Brewhouse Efficiency: 72.00 %
Est Mash Efficiency: 78.9 %
Boil Time: 90 Minutes

Ingredients:
------------
Amt                   Name                                     Type          #        %/IBU         
7 lbs                 Pale Malt (2 Row) UK (3.0 SRM)           Grain         1        60.7 %        
1 lbs 8.0 oz          White Wheat Malt (2.4 SRM)               Grain         2        13.0 %        
1 lbs 2.1 oz          Caramel/Crystal Malt - 80L (80.0 SRM)    Grain         3        9.8 %         
13.6 oz               Chocolate Malt (350.0 SRM)               Grain         4        7.4 %         
9.1 oz                Roasted Barley (300.0 SRM)               Grain         5        4.9 %         
7.8 oz                Milk Sugar (Lactose) (0.0 SRM)           Sugar         6        4.2 %         
1.00 oz               Magnum [12.00 %] - Boil 60.0 min         Hop           7        40.8 IBUs     
1.0 pkg               Denny's Favorite (Wyeast Labs #1450) [12 Yeast         8        -

 

[ajdelange]

With that grain bill likely mash pH would be about 5.57 in an alkalinity free water which is probably OK but a little acid to nudge it down to 5.5 probably wouldn't be a bad idea (this of course subject to the usual caveats about the models of the malts I put into the spreadsheet not exactly matching the actual malts you use). So as I said in #6: no alkali.

 

[Auger]

So if I'm getting grainy/husky off flavors in darker beers, it may be due more to a too-hot sparge vs. water chemistry?

 

[ajdelange]

It's my conviction that if one has off flavors in a dark beer it is usually because too much dark grain has been used. It doesn't take much to load a beer with lots of flavor and color. Recognizing that there may be special cases if pressed I' say 10% for the black malts is about as high as you would want to go. That's based on the observation that 10% seems to be enough to get a pH < 6 with water of alkalinity of 1 mEq/L or less.

 

[mabrungard]

I agree that too much roast malt in the grain bill can produce off flavor. Other causes can be too low kettle wort pH and too high kettle wort pH. Thin and acrid roast flavor is typically a result of the pH being too low. Astringent and harsh roast flavor is typically a result of high pH.