What substance to use to change mash pH

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mew

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I've heard of people using CaCO3 to make a mash more basic, but is that the only option? and what about making the mash more acidic?
 
I bought a tub of the 5.2 PH Buffer, but I keep forgetting to add it to the mash. That's supposed to do a kick-ass job of keeping you in the right range and improving efficiency.
 
There's a lot more to water chemistry than just acidity/alkalinity. My tap water is quite alkaline (pH 7.9), but much of that alkalnity comes from bicarbonate. I use 88% lactic acid (about 1.5 tsp/8 ml per 4 gal of water) to reduce the amount of CO3 in my water, and subsequently lowering the pH of my mash to acceptable levels.

I recommend getting a water profile report from your local utility, and playing around with the water profile spreadsheet on howtobrew.com.
 
And let's not forget the good old acid malt. Weyerman says that 1% of acid malt lowers the mash ph by 0.1. But unfortunately this is rather dependent on the buffering capacity of the mash.

And yes, trying to understand water and mash PH would be a very good start. As texasgeorge pointed out, Palmer is a good source for that. It recently had to start worrying about that and it took me quite a while to understand the concept.

Kai
 
Hmmm... David_42 and a few others swear by it. I did get it added to the porter, but didn't remember it until late in the mash, so we'll see.
 
pH 5.2 does not add a "funky flavor", it's just phosphate compounds. As far as I can tell, it has no flavor whatsoever.
 
What should I use to make the mash more acidic?
 
mew said:
What should I use to make the mash more acidic?

Acid, but it depends on your water profile.

Lactic acid works for me because I have an excess of CO3 in my water. You want to be careful adding Sulfuric acid or Phosphoric acid because, as the names imply, they will add sulfur or phosphorus, respectively, to your water. Hydrochloric will add chlorine as well.

Go to your city's website and you should be able to find a recent (2006) water profile report. Post your city's levels of Ca, Mg, Bicarbonate (CO3), sodium, chloride, sulfate, and the nominal pH level and that'll get us started. Most of these measurements are in ppm, which is synonomous with mg/L.

Finally, it's important to know what kind of beer you want to make. More alkaline water is preferrable for dark stouts, where as a more acidic, low CO3 profile is better for lighter brews.
 
mew said:
I've heard of people using CaCO3 to make a mash more basic, but is that the only option? and what about making the mash more acidic?

Some excellent intro articles from Zymurgys past escape me so I'll paraphrase from data from Fix's "The Principles of Brewing Science"...

Calcium tends to acidify the mash.... so adding Calcium chloride and/or Calcium Sulfate (in its hydrated [gypsum] or unhydrated forms) will acidify the mash... the reason is that the calcium reacts with the hydrogenated phosphates to precipitate calcium phosphate (the white-ish residue on the bottom of your brewpot after a long boil).

Ca2+ + HPO42- --> H+ + Ca3(PO4)2
(calcium cation)+(phosphate anion) --makes-->(acid)+(precipitated salt)


Unlike calcium chloride and calcium sulfate (which contain anions that are the conjugate bases of strong acids), Calcium carbonate contains the carbonate anion which is by itself a weak base.... therefore carbonate can react with those H+ acids released by the reaction of calcium and phosphate and neutralize the effects of added calcium...

The trick with using CaCl2 and CaSO4 is not to add too much ions to the mix. Ions in excess can add off-flavors. Fix recommends if acidification is really needed... that food grade acids such as lactic acid can be used (he even states that some breweries use sulfuric acid.) So I guess my question is.... (after the rambling...)

...is how acidic are we talking here? If you post the concentrations of CO32- [carbonate] and bicarbonate [HCO3-] from your water source and if you tell me a desired pH, I can post the amounts of lactic acid, phosphoric acid, or sulfuric acid you would need to add to get there... or... the previously mentioned buffer can take you all the way to 5.2!

Peace,
kalTOrak
 
I've requested a water report in the mail, but online all it said was that the water is very soft and there are few metallic ions in it. It also has a small amount of chlorine. Thanks for the help.
 
Your city/local municipal water district may have it's water report on it's website. Here in LA I just looked up on the LADWP site and found the annual water report all there ready to print out. Easier than the phone or mail.
 
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