Distilled Water for Porter - do I HAVE to add carbonates?

[TrojanAnteater]

I'm brewing a small batch of robust porter (2'ish gallons)... if I plug my grist into E-Z water calculator, with no salt additions of any kind, it gives me a room temp mash pH of 5.63 (references optimal as being between 5.4-5.6). This is using plain old distilled water.

The grist is:
4.75 lb Marris Otter (80%)
0.38 lb rolled oats (6.3%)
0.25 lb Crystal 60L (4.2%)
0.50 lb Chocolate Malt (8.4%)
0.06 lb Black Patent (1%)

The minerals I would plan to add in are Ca, Cl, SO4.
Adding enough CaCl2 and CaSO4 to get the following levels brings my mash pH down to 5.58 (and residual alkalinity of -77)

Ca: 97
Cl: 113
SO4: 82

Obviously I don't want to make the pH go up any higher, so I don't need to add carbonates, right? Basically, the water would be completely carbonate free. Is that ok in this situation?

Thanks and Cheers
Steve

 

[ajdelange]

We might have a discussion about the accuracy of the pH prediction (EZ is reputed to come in high) but in principle, no, you don't necessarily need bicarbonate to make a dark beer. Whether you do or not depends on whether the proton surfeits of the dark malts are greater than the proton deficits of the base malts. This depends, of course, on how much of each malt is used and on the surfeits/deficits of each malt. We might argue here that you need acid rather than bicarbonate in order to nudge the pH down a bit. This acid could come from more dark malt or it could come from sauermalz or it could be added lactic or phosphoric acid.

In general it is perfectly OK to have bicarbonate free water in brewing. Bicarbonate brings nothing to the table other than the ability to absorb protons in cases where the dark malt proton load is greater than what the base malts can absorb. In absorbing these protons bicarbonate is converted to CO2 gas and leaves the mash (or most of it does anway).

 

[Yooper]

The minerals I would plan to add in are Ca, Cl, SO4.
Adding enough CaCl2 and CaSO4 to get the following levels brings my mash pH down to 5.58 (and residual alkalinity of -77)

Ca: 97
Cl: 113
SO4: 82

Obviously I don't want to make the pH go up any higher, so I don't need to add carbonates, right? Basically, the water would be completely carbonate free. Is that ok in this situation?

Thanks and Cheers
Steve

I used to use EZ water, but it always predicted high for me and sometimes it was as high as .3 over the actual pH, so consider that.

I would NOT go with such high Cl and So4 numbers. That profile will be quite "minerally" and not at all necessary. You can take out the sulfate completely, and reduce the chloride to under 100 ppm. A mash pH of 5.3-5.6 is good.

 

[TrojanAnteater]

Thank you guys, I'll probably start playing around with Bru'n Water then which I already had downloaded anyway. And appreciate the recommendation to lower the minerals. Will give that a try! Thanks

 

[mabrungard]

If you can keep the mash pH in the 5.4 to 5.6 range, that tends to smooth the roast character of beers like porter. If you are starting with distilled water, you don't have any alkalinity and there is the potential that the combination of the roast malts and any calcium or magnesium salts added to the mash could depress the pH lower than desirable. You have several options to avoid low pH: Add alkalinity, don't add calcium or magnesium salts to the mash, reserve the dark grains from the main mash and add them late.

In the case of not adding those salts or the dark grains to the mash, their pH lowering effect will be suffered in the kettle. So you can't avoid the effect if there is insufficient alkalinity in the mashing water. I recommend getting the mashing water alkalinity correct for that reason. Since you are starting with the blank slate of distilled water, using baking soda or pickling lime are very good options for adding alkalinity. Don't use chalk since it does not dissolve in a timely manner.

Enjoy!

 

[TrojanAnteater]

You guys were very right, when plugging all this info into Bru'n Water, my pH would be down around 5.2 @ RT (0.3 lower than what EZ Water said). So I'm decreasing the Cl And SO3 a bit and adding in a bit of Sodium Bicarb plus a little Chalk to the mash to boost my Calcium level (and RA, without getting too much Sodium) a little bit. Gets it up to 5.5 pH.

@Mabrungard - Re: chalk dissolving.... I normally treat my water the night or morning of brewing.... but with the chalk (which I have but haven't used in a loooooong time), it'll dissolve fairly readily after dough-in right?

 

[ajdelange]

No, it won't. I call it the 'gift that keeps giving'. As most of the spreadsheets in the old days didn't understand how to model the bicarbonate system they would advocate adding twice the chalk that the stoichimetry called for. The good news was that it wouldn't dissolve in the mash (in which case the mash pH would have zoomed high). The bad news was that the undissolved part went on into the lauter tun and, apparently, a fair part of that went on into the kettle and even into the fermenter. Thus, as it absorbed acid, it continued to cause a rise in pH. The result was, unsurprisingly, pretty bad beer.

Carbonate is slow to react in mash and I think this may be because of the pH as if you pour concentrated acid over, even vinegar, it fizzes right up. You would do well to avoid chalk in brewing (unless you are taking steps to insure that it is getting completely dissolved). You can use Ca(OH)2 for alkalinity where it is needed with the assurance that it will react quickly.

 

[mrwizard0]

Aj, pickling lime is not on bru'n water spreadsheet. Is there any way to show its effects so we can add the right amount? I know you don't make that program but you are the water chemistry master

 

[IKR]

The version of Bru'n Water I use (1.6, I think) definitely has pickling lime included in the program. Just an FYI.

 

[mabrungard]

I'm hoping you are using version 1.16 and not 1.6. There have been many worthwhile changes. Yes, pickling lime is one of the mineral choices. If your starting sodium content in your water is very low, then another good choice for alkalinity addition is baking soda. Remember, it is ALWAYS better to brew with too LITTLE alkalinity than too much. If in doubt...leave alkalinity out!

 

[ajdelange]

Aj, pickling lime is not on bru'n water spreadsheet. Is there any way to show its effects so we can add the right amount? I know you don't make that program but you are the water chemistry master

Sure. I'm going to spell out the reasoning here because I have to go through it anyway and perhaps it will be instructive. At mash pH sodium bicarbonate is almost but not quite a strong base. In being taken to pH near mash pH one mmol (61 mg) of bicarbonate absorbs about w = 0.9 mEq of protons. Values for other pH's can be obtained from w = 1.894 - 0.184 pH. If you want to be more precise still use w = -3.0083+ 1.6539*pH -0.17208*pH*pH for any mash pH value between 5 and 5.7. Thus it takes 61/w mg of sodium bicarbonate to absorb 1 mEq of protons.

Calcium hydroxide is a strong base. One mmol of it (74.1 mg) absorbs 2 mEq of protons at any mash pH. Thus it requires 74.1/2 mg of calcium hydroxide to absorb 1 mEq of protons. Calcium hydroxide is therefore
(61/w)/(74/2) times as potent a proton absorber in terms of weight and for each gram of baking soda calculated one should use (74.1w/122)= grams of calcium hydroxide. For w = 0.9 this is 0.54 grams Ca(OH)2 for each calculated gram of NaHCO3. As a function of pH it is 1.15037 - 0.10452*pH grams/gram

 

[IKR]

My mistake. I rattled off what version I thought it was but missed a number It's definitely Version 1.16 and I'm happy with it.