[jlap]

Besides having enough Ca for good conversion, I noticed a big difference in the clarity of my wort after hot break and final beer when I started boosting Ca levels into the 50-75ppm range in the kettle.  Not sure of a cause-effect but maybe someone else can say something about that...

[Pawtucket Patriot]

Hmm. I don't have much calcium in my water and haven't had any conversion issues. I suppose there's probably some calcium in the grain itself though.

[tomsawyer]

Besides having enough Ca for good conversion, I noticed a big difference in the clarity of my wort after hot break and final beer when I started boosting Ca levels into the 50-75ppm range in the kettle.  Not sure of a cause-effect but maybe someone else can say something about that...

I've observed this too.  Might be more due to the pH issue than the presence of calcium.  Bring the pH closer to the isolelectric point of a protein and it helps it drop.

[Kaiser]

I read about positive correlation between calcium and protein coagulation via a mechanism that is different from simply changing the pH.

The first chapter on this page of Brigg's book makes a mention of a correlation between calcium and protein coagulation. But that's all I was able to find so far.

When it comes to beer clarity, the formation of calcium oxalate in the beer can also create haze. Calcium oxalate is not sufficiently precipitated in the fermenter when there are inadequate levels of calcium present in the beer.

Kai

[tomsawyer]

Could also be that the proteins are in fact charged and the salts screen these charges, allowing more hydrophobic interaction that results in coagulation.

All I know is, when I started just adding a couple grams of calcium chloride I got much more of that egg drop soup look in my kettle.  The effect was quite dramatic, and pushed me into learning more about water chemistry (which I was purposely avoiding for a long time).

[denny]

All I know is, when I started just adding a couple grams of calcium chloride I got much more of that egg drop soup look in my kettle.  The effect was quite dramatic

I experienced exactly the same thing.  I made a pils recently where I really concentrated on the water, and it was the nicest looking break I've gotten in nearly 400 batches.

[Pawtucket Patriot]

Another follow-up question: Is residual alkalinity (RA) really most important during mashing?  How concerned should I be about it with regard to my final, post-boil wort?

[Kaiser]

Mash and boil pH matter. But if the mash pH is optimal, the boil pH is generally fine as well. The boil pH can end up much higher than the mash pH if you use lots of high residual alkalinity sparge water.

Kai

[tomsawyer]

All I know is, when I started just adding a couple grams of calcium chloride I got much more of that egg drop soup look in my kettle.  The effect was quite dramatic

I experienced exactly the same thing.  I made a pils recently where I really concentrated on the water, and it was the nicest looking break I've gotten in nearly 400 batches.

I can believe that, pils malt in general seems to have the most protein of any base malt I've used.

[denny]

I can believe that, pils malt in general seems to have the most protein of any base malt I've used.

I'd agree with that.  But I'd used several bags of the same malt from the same lot and hadn't experienced a break like that until I got my water dialed in.

[mabrungard]

I'm finding that residual alkalinity is only a component to understanding and predicting a desirable mash pH.  The beer color versus residual alkalinity recomendations that I've made in the past and many water calculators use, are woefully inadequate. 

It turns out that the variation in grain acidity that Kai deciphered over a year ago is very key to the refinement in our ability to assess what might happen in the mash before we actually brew.  To brewers that don't have pH meters and the time or inclination to fine tune their brewing water, there is the potential that better water calculators can be devised. 

Another thankful property of our brewing grists appears to be its tendency to buffer the over application of either gypsum or calcium chloride and not push mash pH too low.  I've complained in the past about brewers that espouse creating water with negative residual alkalinity.  My research suggests that the mash buffers prevent these mineral additions from pushing pH down.  So, that doesn't matter too much.  If you want to create negative RA brewing water, it is OK, but it doesn't really do anything extra for the mash. 

Mash water chemisty is still very complicated, but hopefully we will move beyond the misinformation that is out there now and devise tools that a regular brewer can apply.  I'm trying and I know there are others.

[Kaiser]

My research suggests that the mash buffers prevent these mineral additions from pushing pH down.  So, that doesn't matter too much.

That sounds interesting. But i did find that calcium and magnesium salts do lower the pH. Maybe not at the rate suggested by the residual alkalinity formula but still fairly linear up to at least up to a calcium hardness of 800 ppm as CaCO3, which is well above what brewers would add.

Kai

[mabrungard]

Kai,

That is an interesting finding, but possibly I'm misunderstanding you.  You're telling me that you're depressing the residual alkalinity to around -400 (this assumes there is maybe 150 ppm HCO3) and the pH continued to drop?  Did the slope of the pH per RA relationship became much shallower around the low 5 range?  I would be surprised to hear that the phosphate buffer system would allow the pH to drop like it does in the upper 5 to 6 range (ie, the slope of that line is the same in the upper range as the low 5 and under range). 

[Kaiser]

The data is here: http://braukaiser.com/documents/effect_of_water_and_grist_on_mash_pH.pdf

Page 7, Figure 10.

Kai

[mabrungard]

Unfortunately, the figure does not disprove what my original contention was.  Possibly I stated it incorrectly. 

The buffer system in the mash prevents the pH from dropping much lower than the low 5 range.   Adding a bunch of calcium or magnesium in order to reduce RA into the negative range has little effect.  That is a good thing. 

Maybe Kai could continue the experiments he presented in that excellent paper and see if my contention is incorrect?  I think that something other than a Ca or Mg vs. phosphate buffer interaction is needed to bring the pH lower than the low 5 range (ie acid). 

The point I'm trying to make is that it appears to me that a normal mash is naturally incapable of dropping below about 5 without adding an external acid.  (PS: I see that some dark cyrstal & roast malts do have enough acidity to drop below 5, but those are used sparingly in a normal mash).

Good work, Kai.