My Stout water profile. Does it seem ok?

[RKi]

I've been having some problem with my dark beers lately, and would love to some input on the changes i've made.

Basically, i live in a very soft water area:
Total hardness as CaCO3: 32 --all in ppm
Calcium : 8.82
Magnesium : 2.43
Chloride : 11.59
Sulphate : 15.86
Alkalinity as CaCO3 : 33

I've been using the excellent bru'n water spreadsheet to great effect on my pale beers, but that was always going to be relatively easy with my water to be honest.

My recent dark beers have all been awful and i think i finally found out why. I'd been idiotically using Sodium Carbonate by mistake instead of Sodium Bicarbonate (Baking Soda) to increase the alkalinity of my mash. I carried out a small experiment where i added the same amount of Baking Soda and Sodium Carbonate to 2 seperate pints of water and found that the Sodium Carbonate pint tasted absolutely awful, making me retch. I actually found out that its often referred to as Soda Ash and is often used in the manufacturing process of washing poweder for clothes? The Baking Soda sample was merely a bit weird and salty. Basically my Stouts brewed with Sodium Carbonate would have massively muted flavours, awful head retention and deteriorate over time as opposed to improve. I'm 90% sure this is why my Stouts suck, does this seem like what's likely caused it?



Right, now on to the changes i've made. Obviously i've changed the Sodium Carbonate for Sodium Bicarbonate (so embarassing). I've elected to target a water profile similar to London but with added CaCl2:

Ca:68
Mg:2
Na:65
Cl:95
SO4:45
HCO3:278

Heres the grist:

Maris Otter 3L : 1.85kg (62.4%)
Flaked Oats 2.2L : 372g (12.5%)
Extra Dark Crystal Malt 160L : 268g (9%)
Chocolate Malt 357L : 238g (8%)
Brown Malt 65L : 134g (4.5%)
Black Patent Malt 525L : (3.5%)

I use a grainfather and the calculator recommended 11.5L for the mash and 7L for the fly sparge. (11L Batch Size)

I used 4.4g Baking Soda and nailed my mash pH of 5.5 exactly(i was doing that with the Sodium Carbonate too though....)

Basically i'd just love feedback about the above and whether my water profile looks good for a stout / porter etc. Also, thoughts on whether the Sodium Carbonate was likely causing my beer to be undrinkable.

 

[mabrungard]

Yep, chemicals are unforgiving that way! Sorry you ruined batches when using the wrong chemical. Sodium carbonate is a much stronger caustic instead of basic buffer like sodium bicarbonate.

That profile looks similar to the water quality encountered from the Chalk wells in London that the Porter brewers historically used and should produce a decent Porter.

 

[RKi]

Thanks for the reply Martin. Do you switch up your water profile much between Stouts and Porters generally?

 

[mabrungard]

Yes, a bit. The softer character of the roast used in Porters does enable the use of more sodium. However, I find that the sodium is less suited in more roasty stouts. I also caution on the use of sulfate in stouts since the dryness imparted by the stronger roast notes in stout, may not need much or any more drying from sulfate in the water. 45 ppm sulfate should be fine in a Porter, but MIGHT be too drying in a stout.

 

[ajdelange]

No problem really. Sodium carbonate is a buffer and sodium bicarbonate is a buffer with the difference being that sodium carbonate buffers first at pH 10.38 and then at 6.38. It thus, in the course of getting to mash pH, absorbs a little over twice as many protons (1.9/.9 = 2.111) per mole as sodium bicarbonate (at pH 5.4). Given this you may certainly use sodium carbonate instead of sodium bicarbonate. Just use
(.9/84)/(1.9/106) = 0.597744 (60%) as much by weight.

This assumes that the program knows that a mmol of bicarbonate ion absorbs 0.9 mmol of protons. Most (the most popular ones) don't. Their authors have been made aware of this but whether any of them have fixed their programs or not is unknown. They can comment on this here.

If you are not certain that the program handles this properly assume that when it tells you to use x grams of sodium bicarbonate it is telling you it wants x/84 Eq of proton absorbing power. As you are really only getting 0.9*x/84 with you should increase the sodium bicarbonate weight to x/0.9. To use sodium carbonate you would want 60% of x/0.9: (x/0.9)*(.9/84)/(1.9/106)=(x/84)/(1.9/106)

Note that these numbers have been edited as I forgot the 2nd sodium in N2CO3 yesterday. Also, freed from the strictures of trying to respond on a cell phone, I have reworded for what I hope is a clearer presentation.

 

[RKi]

Unfortunately i was using it in the same volumes you would Sodium Bicarbonate. Probably due to the fact i thought i was using Sodium Bicarbonate :[

 

[ajdelange]

The densities of the two salts are a bit different and measuring by volume is, at best iffy, anyway. But if you follow No. 5 (which, please note, has been edited) then you can look up the densities of the two salts and see what the ratios would be by volume.

The important point is that there is absolutely nothing wrong with using the carbonate as opposed to the bicarbonate as long as you adjust the amount of the latter to reflect its greater alkalinity and greater molecular weight.