Adding Mash and Kettle salts all into mash to adjust PH

[Rivenin]

Weird title, i apologize!

So i brew with all RO water, so i build everything from scratch.
However, with the batch coming up this weekend, i forgot to buy the acid malt and do not want to go to the LHBS to get 4oz of acid malt.
So i was playing with Bru'n'water and came up with this conclusion.

i do the pale ale profile, i'll add 2g/g of gypsum, .5 g/g calcium chloride and .6g/g baking soda to get the water profile i'm after. However, the mash PH is at 5.5 and of course, i'd like it at 5.2 or there about.

So i changed it up and doubled everything going into the mash and nothing in the kettle (except for the baking soda) (the mash and sparge water are the same amounts as well) so in theory everything is still the same, just going into the mash.

If i do this, my alkalinity is up around the 80s and my mash PH is at 5.2 where it should be, then i can sparge and add nothing to the kettle.... would that work??

 

[mabrungard]

Why are you adding acid malt to a mash in which you are adding baking soda? They counteract each other!!

In addition, since you are apparently trying to brew a hoppy beer, why are you targeting a mash pH of 5.2? Hop expression and bittering are enhanced by shifting the mash pH slightly higher to 5.4.

 

[Rivenin]

Ah, had no idea 😊 was trying to up the alkalinity. Doing this made my ph jump a bit. Never read the baking soda and acid malt issue... it was aiming for 5.2 because I've heard that is optimal ph for mash conversion... but alas I trust your opinion! 😄
Spreadsheet is at work, but if I recall correctly I would just need to add some of the kettle gypsum to the mash to get it to 5.4... so that works for me!

 

[ajdelange]

Actually 5.4 - 5.5 is a fine pH for mashing. 5.2 (as measured at room temperature) would be below the lower limit of the desired range as pH at mash temp would quite possibly be under 5. Not sure that the consequences of a pH as low as 5.2 would be disastrous but 5.4 - 5.5 is a better target. Now how you get that depends on your water, your malts and what you add to the water/mash. You didn't give a lot of information about any of those but some general remarks can be made based on a few assumptions. Assuming a mash pH of about 5.4, the 4 Oz of sauermalz and 0.6 g/g baking soda just about offset one another (with the bicarbonate raising pH by about 0.1 and the sauermalz lowering it by about 0.1) so there is no point in using both unless you want the flavor from the sauermalz (which would be very subtle indeed and not typically sought after in an ale). The implication of this is that if you don't want to go to the LHBS to get 4 Oz sauermalz you can achieve the same effect by simply eliminating the bicarbonate.

The next observation would be that the bicarbonate probably shouldn't have been in the formulation in the first place. But of course I don't know that you aren't using a relatively acidic base malt with some very acidic colored malts. For example, if I wanted mash pH of 5.4 and used a base malt with pHDI of 5.6 and a 60L caramel with pHDI of 4.8 and wanted a mash pH of 5.5 I would need a bit over 2 grams of bicarbonate (assuming typical malt buffering). OTOH if I use a base malt with pHDI 5.8 and a 20L caramel I would need 2% sauermalt to hit 5.4. So as you can see it depends a lot on malts.


The next observation is that you have a lot of gypsum - enough to give sulfate of almost 300 ppm. That's a lot of sulfate but I know a lot of people like that and if it what you are after then by all means do it. The high gypsum plus calcium chloride means high calcium to the extent that it will lower pH by about 0.15 i.e. its pH control effect is more than that of either the baking soda or the sauermalz.

Finally, a distinction needs to be drawn between mash pH which determines malt related flavors. It is to optimize those that mash pH needs to be in the 5.4 - 5.6 region. Then there is kettle pH which determines, to some extent, hops utilization. The higher kettle pH the higher hops utilization as hops bittering substances are acids and the higher the pH the more dissociated they are and the more dissociated they are the more they isomerize. So if you goal is to save money on hops, then you would add bicarbonate (or some other base) to the kettle to raise the boil pH. Prudence would then dictate that you add acid towards the end of the boil in order to get the final wort pH into the range that is more suitable for knockout wort (5 - 5.2?). Commercial brewers are, of course, interested in saving on their hops costs and strike kettle pH compromises (or make pH adjustments) but for a home brewer who wants more hops bitterness buying a couple $ more hops is a much easier solution.

I know all this must seem terribly complicated and I wish I could give some simple advice which I could guarantee would work for you. Your 2g and 0.5 g additions of, respectively, calcium sulfate and calcium chloride will probably work assuming you have reasonable base and caramel malts by relying on the high calcium level for pH reduction. I'd guess you would have a pH between 5.32 and 5.54 and anything in that range should be OK (though within that range it is probable that some subrange would be best) both for malt conversion and hops utilization. If not bitter enough, use more hops.

 

[fogley]

AJ,
I have seen you do calculations like you have above many times. How do I go about learning how to do that ? Can you point me to some references or resources?

I see you referencing pHDI (that's pH in distilled?) and calculating pH and subsequent necessary acid/sauermalz additions. Also seems you know how to calculate pH drops caused by salts. I would like to be able to figure this stuff out and am willing to study the methods/equations.

thanks!

 

[Rivenin]

Perfect, thanks gents!

AJ, thank you VERY much for the lengthy response. Had to read it twice, but it all made sense :beer:
The water book IS currently at my desk as well, thats on the docket to read after a few other beer titles... so i'll be reading your words shortly!

 

[ajdelange]

I have seen you do calculations like you have above many times. How do I go about learning how to do that ?

By learning to count protons. It really turns out to be a bookkeeping problem.

Can you point me to some references or resources?

You can try http://wetnewf.org/pdfs/estimating-mash-ph.html. That article lays out the procedure in pretty concise format. The problem is that it may be too concise. While it is directed at people with no or little background in chemistry those that have some will be able to say "Oh yes, I see what he is doing." At the samse website you will find a spreadsheet that implements all the math in the article and a set of slides from an MBAA presentation on this very subject. I'd say look at that stuff and, if you are at sea, start with general inorganic chemistry and work up until you understand Henderson-Hasselbalch. That's what it is all based on.

I see you referencing pHDI (that's pH in distilled?)

Yes, that is the pH of the single grain in a mash made with de-ionized water.

..and calculating pH and subsequent necessary acid/sauermalz additions

Sauermalz is treated just as any other malt is. That's described in the article.

Also seems you know how to calculate pH drops caused by salts.

Kolbach (you'll find a translation of his paper at wetnewf.org as well) observed that 3.5 mEq of calcium could cancel 1 mEq of alkalinity. This implies that when calcium reacts with phosphate each mEq releases 1/3.5 mEq of protons. These go into the balance sheet with protons absorbed and released by other sinks/sources. The equivalent number for magnesium is 1/7 mEq/mEq.

I would like to be able to figure this stuff out and am willing to study the methods/equations.

It took me a long time to figure this stuff out. I would hope that some of the insight I have gained over the years may be of help to you. The proton counting, while it is an old concept in chemistry in general, was something that I only fairly recently thought of as having application to brewing mash chemistry hence the fairly recent date on the MBAA presentation. Some of these ideas got into Palmer's water book so you might want to read that too.