75 replies to this topic

[MtnBrewer]

I had a discussion with AJ awhile ago about ion additions and how they lower pH. Calcium in the mash reacts with  phytin in malt. This allows the enzyme phytase to to dissociate  phytin into calcium, magnesium phosphates, and phytic acid which lowers mash pH. I believe the enzyme phytase is deactivated after the mash so the BK addition shouldn't affect pH too much (if any) My discussion with AJ: Me: Is it just in the mash that these salts will drop pH?  AJ: That is correct. The calcium and magnesium react with the phytins in the malt to create an acid that actually does the pH reduction. That does not apply in the sparge water or kettle. To acidify in those instances, you have to add an actual acid like phosphoric or lactic.

That makes perfect sense.

[Big Nake]

That makes perfect sense.

It really does and it answers the question too.  Adding CaCl and/or CaSO4 to the mash lowers the mash pH because of the interaction with the malt.  But adding a bunch of this stuff to the kettle does not lower the pH of the wort because there is no malt interaction.  Very interesting.  So you could add however much to the mash to keep the pH in check and add however much to the kettle as "flavor" additions and if you really needed to lower the wort pH, an acid would be necessary.  Lightbulbs just went on.  Lightbulbs.

[neddles]

I had a discussion with AJ awhile ago about ion additions and how they lower pH. Calcium in the mash reacts with  phytin in malt. This allows the enzyme phytase to to dissociate  phytin into calcium, magnesium phosphates, and phytic acid which lowers mash pH. I believe the enzyme phytase is deactivated after the mash so the BK addition shouldn't affect pH too much (if any)

 

My discussion with AJ:

 

Me: Is it just in the mash that these salts will drop pH?

 

 

AJ: That is correct. The calcium and magnesium react with the phytins in the malt to create an acid that actually does the pH reduction. That does not apply in the sparge water or kettle. To acidify in those instances, you have to add an actual acid like phosphoric or lactic.

Yeah good stuff here. Will definitely put this to use.

 

*Paging Chris Colby, Mr.Colby you have a phone call*

 

And FWIW I think that conversation you had was actually with Martin not AJ.

[MtnBrewer]

It really does and it answers the question too.  Adding CaCl and/or CaSO4 to the mash lowers the mash pH because of the interaction with the malt.  But adding a bunch of this stuff to the kettle does not lower the pH of the wort because there is no malt interaction.  Very interesting.  So you could add however much to the mash to keep the pH in check and add however much to the kettle as "flavor" additions and if you really needed to lower the wort pH, an acid would be necessary.  Lightbulbs just went on.  Lightbulbs.

It's not because there is no malt interaction. It's because the phytase has been denatured. So that would mean that there's some pH drop but maybe not much. As the wort heats up in the boiler it will get to a temperature at which phytase is denatured. Until then, it will still be doing its thing and lowering the pH. Therefore if you add salts after that point you won't get any pH drop.

[Steve Urquell]

And FWIW I think that conversation you had was actually with Martin not AJ.

I had to go dig that thread up. Over 2 years ago. Wow, you are correct. It was Martin.

 

Reason I misremembered was AJ initiated the convo regarding sparge ion additions saying:

 

Adding these salts would have no effect on water pH if they were really CaCl and CaSO4. But a lot of "calcium chloride" contains some calcium hydroxide and so will raise the pH slightly.Unless you want more of these salts in the boil for some reason there is little point in adding them to the sparge water.

 

https://www.homebrew...ay-pics-244963/

Edited by chils, 21 November 2013 - 12:24 AM.

[positiveContact]

It's not because there is no malt interaction. It's because the phytase has been denatured. So that would mean that there's some pH drop but maybe not much. As the wort heats up in the boiler it will get to a temperature at which phytase is denatured. Until then, it will still be doing its thing and lowering the pH. Therefore if you add salts after that point you won't get any pH drop.

 

i've been adding in kettle additions before the boil gets going.  how about you guys?

[Steve Urquell]

i've been adding in kettle additions before the boil gets going.  how about you guys?

I add equal amounts to the mash and sparge assuming there is still enough phytase active to lower sparge pH. I've read plenty about RO water not needing acid additions to keep it below pH 6.0, but IME most of my sparges will come in at 5.8-6.0 without an acid addition. THB, I throw 1-1.5 tsp of 10% phosphoric acid in the sparge depending on the grist color anymore and forego the sparge pH check.

 

I'll also state that I don't particularly like the taste of large additions of gypsum with 80-100 ppm SO4 being the high end for me in IPA and APA, 30-45ppm in German Pils, 50-75ppm in British ales, and 0 ppm in malty beers or Czech lagers.

[positiveContact]

i haven't pushed beyond 150 ppm on SO4 yet and so far i'm liking it.  i'm at least planning to go close to 300 ppm but probably not over that for now.

[Big Nake]

I haven't added anything to the kettle in a long time.  The next time I make a beer where I would like a little extra crispness, I'm going to add some gypsum to the kettle and see how I like the results.  I am making my Signature Ale as I type and the mash went very smoothly with my meter and I will hoist a beer (at a more appropriate time) to you guys who have helped bring all of this into focus.  I was just thinking this morning about all of the things I look at when I'm preparing the mash and how much more detailed I'm getting with my beers.  Control is getting better, beers are getting better, toolbox is filling up with tools and all is good in Beerville.  Cheers Brothers.

[MtnBrewer]

HODE UP!!!Water says differently.

The phosphate is primarily bound up as malt phytin and is hydrolyzed during the mash. Phytin is a mixed potassium and magnesium salt of phytic acid. This hydrolysis is (or would be) catalyzed by the enzyme phytase, but phytase is readily denatured by kilning in all but the lightest malts. Fortunately, the hydrolysis occurs anyway and the various phosphate ions are available for reaction with calcium.

[Brauer]

I had a discussion with AJ awhile ago about ion additions and how they lower pH. Calcium in the mash reacts with  phytin in malt. This allows the enzyme phytase to to dissociate  phytin into calcium, magnesium phosphates, and phytic acid which lowers mash pH. I believe the enzyme phytase is deactivated after the mash so the BK addition shouldn't affect pH too much (if any)

 

My discussion with AJ:

 

Me: Is it just in the mash that these salts will drop pH?

 

 

AJ: That is correct. The calcium and magnesium react with the phytins in the malt to create an acid that actually does the pH reduction. That does not apply in the sparge water or kettle. To acidify in those instances, you have to add an actual acid like phosphoric or lactic.

 

HODE UP!!!Water says differently. 

 

That sounds like the classic acid rest reaction.  That is usually considered to be a very slow reaction.  Also, phytase is thermally unstable (optimal temp for an acid rest is 86-126F), I was also under the impression that little phytase survived kilning in all but the palest of malts.   Doesn't calcium reduce pH as effectively for pale malts as it does more darkly kilned malts?

 

Phytate (phytic acid), however, is another component of the mash that reacts with calcium, releasing hydrogen ions and lowering pH.  That occurs in both the mash and the kettle (Briggs, Malting and Brewing Science).

 

Inorganic phosphate reacts with calcium, causing it to precipitate, decreasing the phosphate buffering capacity trying to keep the pH high, and releasing the acid tied up by the buffer.  Anyone who has ever tried to add calcium to a phosphate buffer in the lab is familiar with that reaction.  That would probably occur in the kettle as well as the mash.

 

I don't make kettle additions, though, so I don't have any practical experience with adding calcium at that point.

[neddles]

HODE UP!!!Water says differently. 

Funny I just read that myself. Wish Martin were still around to pick his brain.

[MtnBrewer]

That sounds like the classic acid rest reaction.  That is usually considered to be a very slow reaction.  Also, phytase is thermally unstable (optimal temp for an acid rest is 86-126F), I was also under the impression that little phytase survived kilning in all but the palest of malts.   Doesn't calcium reduce pH as effectively for pale malts as it does more darkly kilned malts? Phytate (phytic acid), however, is another component of the mash that reacts with calcium, releasing hydrogen ions and lowering pH.  That occurs in both the mash and the kettle (Briggs, Malting and Brewing Science). Inorganic phosphate reacts with calcium, causing it to precipitate, decreasing the phosphate buffering capacity trying to keep the pH high, and releasing the acid tied up by the buffer.  Anyone who has ever tried to add calcium to a phosphate buffer in the lab is familiar with that reaction.  That would probably occur in the kettle as well as the mash. I don't make kettle additions, though, so I don't have any practical experience with adding calcium at that point.

Yes, this is essentially saying the same thing as the section I quoted. Phytase helps the reaction but it will take place anyway without it. Here's a summary equation for the reaction but there are a lot of intermediate steps that are left out:10Ca⁺² + 12HCO₃^- + 6H₂PO₄^-1 + 2H₂O -> Ca₁₀(PO₄)₆(OH)₂ + 12CO₂ + 12H₂O  + 2H⁺¹

 

It's the two protons that cause the pH drop. That big mineral is hydroxyl apatite and it precipitates out.

[Big Nake]

I like beer. 

[denny]

i've been adding in kettle additions before the boil gets going.  how about you guys?

 

Yep.  That way I don't forget.

[MtnBrewer]

Yep.  That way I don't forget.

Same. I weigh out the mash additions, dump them into the mash tun then weigh out the kettle additions and dump them into the kettle. I do all that while the strike water is heating.