[Kaiser]

One of the things I found in my mash pH experiments is that dissolved chalk is able to contribute more alkalinity than chalk simply added to water or to the mash. I don't know why this is by I have been able to confirm than in 5 gal batches.

A side-by-side experiment with a Schwarzbier still awaits official side-by-side tasting but having tapped the 2nd keg a while back I don't taste any significant difference.

However, I decided to write up a description for a fairly practical method of dissolving chalk and building brewing water from it ( http://braukaiser.com/wiki/index.php?title=Building_brewing_water_with_dissolved_chalk) in case others want to try this.

Check it out. It has a fairly lengthy explanation of what happens when one adds CO2 to water to dissolve chalk.

Kai

[1vertical]

Kaiser,
That is a good method thank you again...I still have not messed with my water
chemistry, but I am nearing a pilsner brew day and might consider doing so...

[Kaiser]

That is a good method thank you again...I still have not messed with my water
chemistry, but I am nearing a pilsner brew day and might consider doing so...

If you are just getting into water chemistry and water adjustment, see this as an FYI. To this point there is no proven advantage of actually dissolving chalk. You may give it a try later, when you have brewed a number of beers with chalk simply added in the mash.

I'm not trying to discourage brewers from trying something new though. Maybe at some point we will figure out a valuable practical benefit other than being able to adhere to the German purity law.

Kai

[1vertical]

Well I gotta say I have dissolved chalk two times using the CO2 method you describe
Kai, and then used it in the brew water. The water came from a machine that claims
to DI,UV, & RO treat the water. I asked the attendant and he gave me a little tour of
the inside of the machine. Seems real enough, and if so then the mineral content should
be mostly gone from this water allowing me to add back salts and minerals to custom
taylor brewing water.
The 1st time the beer was very tasty. Second one is still lagering and will
be due to sample in May....prolly cinco de mayo and it is of course a Maibock.
If I can hold myself back that long. 

[Pawtucket Patriot]

Kai,

Have you conducted any experiments to see how soluble chalk is in water and/or wort?  If so, is there a general rule of thumb?  I know Martin's Bru'n Water calculator indicates that chalk is only soluble in water/wort up to around 50 ppm (~.19g/gal).

[narvin]

Has anyone ever pre-mixed their chalk with the roasted malts in the grain bill and added a little of the strike water before adding to the rest of the mash?  Seems like the pH would be a lot lower and perhaps dissolve the chalk better, but I've never tried it.

[Tim McManus]

Here's a pretty good discussion of chalk and the mash.  Lots of links to follow in it too.

http://www.homebrewersassociation.org/forum/index.php?topic=5040.0

[Pawtucket Patriot]

Here's a pretty good discussion of chalk and the mash.  Lots of links to follow in it too.

http://www.homebrewersassociation.org/forum/index.php?topic=5040.0

Great information!  I forgot about that thread.

As a follow-up question, I am still a little confused about whether and how much Ca chalk adds to wort.  If anyone has data on the rate of Ca contribution up to chalk's saturation point, it would be helpful.

[Kaiser]

As a follow-up question, I am still a little confused about whether and how much Ca chalk adds to wort.  If anyone has data on the rate of Ca contribution up to chalk's saturation point, it would be helpful.

I'm touching on that in one of my recent blog posts: http://braukaiser.com/blog/blog/2011/02/27/i-think-we-figured-out-whats-the-problem-with-chalk/

If it is true that chalk does not completely dissolve in the mash we should assume that only the part that contributes to raising pH contributes Ca to the mash.

Kai

[Pawtucket Patriot]

Thanks, Kai.  It's interesting data.  Do we assume then that the chalk that doesn't get dissolved simply precipitates out of the wort/beer at some point along the brewing/fermenting process?  What I'm getting at is whether the residual undissolved chalk will have an effect on the clarity or taste of the finished product.  I can't say I've noticed any impact when using chalk in the past to achieve a mash pH shift or to add flavor ions.

In any event, I think I'm going to limit my chalk additions in the future.  I'm going to try not to use chalk at all to adjust pH.  Instead, I'll just rely on NaHCO3 to raise and lactic acid or acid malt to lower.  As for flavor ions, I think I'll try to get my calcium from either CaSO4 or CaCl.  If the sulfate or chloride levels get out of hand, only then will I use chalk as a calcifier, and only up to around 50 ppm (chalk's approximate saturation point in water/wort).

I suppose that raises another question though: when using chalk as a calcifier, does it only contribute half its calcium potential after reaching saturation?  Or is it more linear than that?

[Kaiser]

Do we assume then that the chalk that doesn't get dissolved simply precipitates out of the wort/beer at some point along the brewing/fermenting process?  

I assume that it is left behind in the spent grain.

I suppose that raises another question though: when using chalk as a calcifier, does it only contribute half its calcium potential after reaching saturation?  Or is it more linear than that?

I found that in most cases only 50% of the undissolved chalk dissolves in the mash. There is little science behind this 50% number, just an observation. I also found that there might be a point at which more chalk won't raise the pH further. Since I think it makes sense that only the part that dissolves and raises the mash pH contributes Ca, I assume that once saturation is hit neither Ca nor alkalinity are provided to the mash. But to confirm that I would have to be able to test Ca in the wort for which I don't have the analytical tools.

Kai

[Tim McManus]

I was just reading Noonan's book, "New Brewing Lager Beer" and on pages 55-56 he talks about a bunch of things including calcium.  I'm not a chemist nor do I claim to know anything about chemistry other than how to spell it, but he states that:

"The serveral salts that may be formed by the acid anions with any given metal may vary in solubility and acid or alkaline reaction according to the electronegative valence of the particular anion involved.  A weak metal and a weakly alkaline anion in solution have very little attraction for each other and stay in solution.  The same metal with a moderately alkaline anion may be precipitated out of solution under certain conditions.  With a strong base, the metal may even be insoluble.  Thus, calcium chloride is freely soluble, calcium sulfate is of limited solubility, and calcium carbonate is nearly insoluble."

You'll have to go back to the rest of the book to put this in better context, but does this explain why chalk doesn't react like other brewing salts?

Oh, I reserve the right to be completely wrong because as I stated before, I claim to know nothing about chemistry.   

[Kaiser]

Chalk is able to dissolve in acidic environments where the carbonate is quickly converted to bicarbonate. Given time I would expect chalk to fully dissolve in the mash.

If you bring chalk in an even lower pH environment that mash you’ll see that it dissolves very quickly.

Kai

[Pawtucket Patriot]

Chalk is able to dissolve in acidic environments where the carbonate is quickly converted to bicarbonate. Given time I would expect chalk to fully dissolve in the mash.

If you bring chalk in an even lower pH environment that mash you’ll see that it dissolves very quickly.

Kai

pH is lower in the boil kettle right?  And IIRC, the pH continues to decrease throughout the boil. Is the boiling wort environment acidic enough to for chalk to fully dissolve?  The reason I ask is because I have used chalk in the past to add Ca flavor ions.  I am wondering how much was actually dissolved.

[Kaiser]

pH is lower in the boil kettle right?  And IIRC, the pH continues to decrease throughout the boil. Is the boiling wort environment acidic enough to for chalk to fully dissolve?  The reason I ask is because I have used chalk in the past to add Ca flavor ions.  I am wondering how much was actually dissolved.

The pH in the BK tends to be higher than mash pH. How much higher depends mostly on the alkalinity of the sparge water. I have seen anywhere from a 0.1 to a 0.3 pH difference. During the boil it tends to fall by about 0.1 pH.

If chalk is present in the boil it should not be able to dissolve at least partially. What doesn’t dissolve shouldn’t settle fast enough and you are likely to get it into the beer where it will have much more time to dissolve.
I don’t think that there is much value to adding chalk to the BK. You generally want to lower your boil pH and not raise it further. If your boil pH is too low, chances are that your mash pH was too low as well.

Kai