Zeroing out alkalinity

[logdrum]

OK, so I'm brewing a cream ale & can easily drop the alkalinity to zero with a small amount of phosphoric acid. (Starting CaCO3=86) My question: what pH should the actual mash water reach? (starting @ 7.6) I trust Bru'nWater's numbers, but also have a decent pH meter & would prefer to measure & titrate.

 

[billl]

5.2 for the mash . The ph of the mash water isn't important and can't be used to predict the mash ph.

 

[Yooper]

OK, so I'm brewing a cream ale & can easily drop the alkalinity to zero with a small amount of phosphoric acid. (Starting CaCO3=86) My question: what pH should the actual mash water reach? (starting @ 7.6) I trust Bru'nWater's numbers, but also have a decent pH meter & would prefer to measure & titrate.

Use the phosphoric acid in the sparge water to get it to 6.0 or a bit lower. Use the phosphoric acid to bring the project mash pH to 5.3 or so, according to Bru'nwater. That should get you close.

The mash pH is the target, not the water pH. Once you lose the water's alkalinity, though, the mash pH should be easily achieved with minor adjustments depending on the ingredients.

 

[mabrungard]

For mashing pale grists, the alkalinity of the brewing liquor can actually be less than zero. Zeroing it out, might not be good enough.

 

[logdrum]

Thanks for the replies. What I'm getting at though is, in the process of removing the alkalinity from the brewing liquor using phosphoric acid, how can I be sure I won't end up with a mash pH that's too low? When brewing this beer today, the strike water measured pH 5.8 (adding the 2.3 ml acid required to remove my alkalinity) but my mash ended up @ pH 5.2 when I was targeting pH 5.4. Is it a matter of trial & error, or is there a more predictable method?

 

[billl]

Sure - the more predictable method is Bru'nWater

You really can't predict mash ph from your strike ph - even with a known water profile. The mash PH will vary substantially with different grain bills.

 

[Sadu]

Bru'nWater does a great job for me.

Enter your grain bill, punch in how much CaCl2 and Gypsum you need to hit your Calcium / Sulfate / Chloride targets, then calculate how much saurmalz or acid you need to bring the mash pH the rest of the way.

Take good readings and good notes of your actual pH and you should start to get a feel for how much adjustment is needed for different styles of beers. I think if you start off lightly with the acid additions there should be little chance of overshooting and ending up too low.

 

[ajdelange]

OK, so I'm brewing a cream ale & can easily drop the alkalinity to zero with a small amount of phosphoric acid. (Starting CaCO3=86) My question: what pH should the actual mash water reach?.

The water should be acidified to a pH equal to the pH you want for the mash. Your job is to get the mash to a target pH and a very reasonable approach is to do that by determining how much acid is needed to get the water to that pH and how much is needed to get the grain to that pH (most beers will require some additional acid for the grains but some won't and, in some cases, you may even have to absorb some acid from the high colored grains if you have enough of them.

If you are using a spreadsheet you can tell it that the water has zero alkalinity if you have treated it with acid to mash pH. It will then estimate the amount of acid (or base) necessary to bring the grains to mash pH (including the phytin/calcium effect if that's at play).