Author Topic: undissolved vs. dissolved chalk  (Read 2216 times)

Online Kaiser

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undissolved vs. dissolved chalk
« on: November 23, 2009, 10:38:02 PM »
I finally published the report about the use of undissolved and dissolved chalk in two batches of my Schwarzbier.

As a background. A while back I noticed that most water spreadsheets don't handle chalk additions correctly when calculating alkalinity. That sparked some experiments including the mash pH experiments that I published a while back. The result was that undissolved chalk has only a limited ability to raise mash pH. At low chalk levels (less than 300 ppm) it seemed that undissolved chalk has only half the alkalinity potential of dissolved chalk.

I wanted to test that in a side-by side and brewed one batch of Schwarzbier with chalk simply suspended in the water and the other one with half that amount of chalk but dissolved with CO2 pressure. The results can be found here:

http://braukaiser.com/lifetype2/index.php?op=ViewArticle&articleId=132&blogId=1

I also updated my water spreadsheet to include dissolved chalk:

http://braukaiser.com/documents/water_calc_v15.xls

Going forward I plan to expand this spreadsheet based on the results of my mash experiments but I have to test that first with my own data. My intention is to make the spreadsheet versatile yet easy to use. Less commonly used or more complicated options would be further down or grayed out.

Check it out and let me know what you think. In particular where there is confusion or something is less intuitive than it should be.

Kai

Offline akr71

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Re: undissolved vs. dissolved chalk
« Reply #1 on: November 24, 2009, 08:28:53 AM »
I know you haven't been able to taste the fruits of your labors yet, but what are the advantages of using dissolved chalk?  You state that dissolved chalk only requires half the normal, undissolved addition and the dissolved chalk seems to affect the pH to a greater degree (even though there is less of the salt).  Are there any other practical advantages?  Does more calcium make it into the fermenter (for yeast heath/nutrition)?

Another great article and experiment!  Unfortunately, I do not have the means to put this into practice (I don't keg yet, so I don't have the CO2 necessary for the dissolving).  I think the homebrewing community owes you a huge thanks for all the experimentation you've done and documentation you've provided us!!
Andy

Amherst, NS - Canada

Online Kaiser

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Re: undissolved vs. dissolved chalk
« Reply #2 on: November 24, 2009, 08:52:42 AM »
I don’t think I can show a big benefit to using dissolved chalk at this point. Brewers have made excellent beers with undissolved chalk and will continue to do so. It’s not that using dissolved chalk is the secret to making a great Schwarzbier. Using dissolved chalk is like using naturally hard water from the tap which brings me to one question I have:

Are there brewers that noticed a difference in beer quality between a dark beer (porter, stout, RIS) that was brewed with naturally highly alkaline water vs. one brewed with water build from scratch by using lots of chalk? I doubt that there will be many who would know that but mabe some brewers with RO systems and alkaline water have brewed similar beers with both waters.

At this point I just want to encourage interested brewers to give this technique of building water a try. Just to get more experience and hopefully a better idea of the benefits and drawbacks. In particular since it is more work.

I’m especially interested in experiences with brewing. My experiments with chalk and other surces of alkalinity showed that undissolved chalk is only able to raise the pH by about 0.2 units before it “stalls”. This seem to means that if the distilled water mash pH of a RIS grist for example is 4.9, you would not be able to get it above 5.1 w/o the use of baking soda, dissolved chalk or naturally alkaline water. I know John Palmer was mentioning that you should not try to build a water with a RA of more than 250 ppm as CaCO3. The question is, what if you build the water with dissolved chalk and are able to raise the mash ph closer to 5.5. Would that improve the quality of the beer or does it not matter anyway. Maybe the malts in a RIS grist aren’t acidic enough to begin with to yield a distilled water pH of < 5.0.

I think I have to brew a RIS myself. I had one at a fellow club member’s house and it was a fantastic beer.

As always, a lot of questions remain.

Kai

Offline crabber

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Re: undissolved vs. dissolved chalk
« Reply #3 on: November 24, 2009, 07:42:40 PM »
Kai, I know I've asked this before, but can you provide any recommended concentrations for creating a chalk brine? 

Online Kaiser

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Re: undissolved vs. dissolved chalk
« Reply #4 on: November 24, 2009, 07:49:46 PM »
Kai, I know I've asked this before, but can you provide any recommended concentrations for creating a chalk brine? 

I have yet to find a formula that determines how much CO2 pressure is needed to hold a known amount of chalk in solution. But I know that you can get about 800 ppm CaCO3 dissolved with about 20 psi.

Kai

Offline tom

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Re: undissolved vs. dissolved chalk
« Reply #5 on: November 24, 2009, 08:20:39 PM »
What happens when the pressure is released?
Brew on

Online Kaiser

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Re: undissolved vs. dissolved chalk
« Reply #6 on: November 24, 2009, 08:26:38 PM »
What happens when the pressure is released?

The excess CO2 will come out of solution, but the chalk should stay dissolved for a while. Once you put that water into the much larger strike/brewing water volume the temporary hardness (which dissolved chalk is) will be low enough that it won't precipitate for a few days even if the CO2 gases out.

Kai

Offline bonjour

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Re: undissolved vs. dissolved chalk
« Reply #7 on: November 24, 2009, 09:13:57 PM »
Again,  some great technical info

Thanks Kai

Fred
Fred Bonjour
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Offline stout_fan

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Re: undissolved vs. dissolved chalk
« Reply #8 on: November 27, 2009, 06:53:04 AM »
Kai,
So for the dense folks here (that would be me) the recommended chalk additions like promash give us to get proper water mineral levels will be off as some of the chalk will stay undissolved. I guess that's why some folks add it directly to the mash.
OTOH, if I take a carbonator cap and add my chalk in the PET bottle, throw in some distilled and gas it, the stuff will go into solution?
I take it has nothing to do with the pressure, but rather the formation of carbonic acid in the water?
Presuming I shake the snot out of the PET bottle, how long will this process take?
Please straighten me out here, thanks.
I'd say something witty down here, but I'm at a bit of a disadvantage in that department.

Online Kaiser

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Re: undissolved vs. dissolved chalk
« Reply #9 on: November 27, 2009, 11:58:13 AM »
So for the dense folks here (that would be me) the recommended chalk additions like promash give us to get proper water mineral levels will be off as some of the chalk will stay undissolved. I guess that's why some folks add it directly to the mash.

Adding chalk to the mash or to the water w/o dissolving it is the same.

(most) Spreadsheets and water calculators will calculate the amount of undissolved chalk necessary. This calculation seems to work until about 300-400 ppm chalk concentration and it assumes that chalk contributes only half its alkalinity potential. You can check that by entering 100 ppm chalk (0.1 g in 1 l water or 0.38 g in 1 gal water). The resulting alkalinity as CaCO3 (i.e. as chalk) will only be 49 or 50 depending on the used formula. Not 100 ppm as you would expect.

While this is not as intuitive as it should be, it seems to work when it comes to predicting mash pH through residual alkalinity.

If chalk is dissolved it does not have this odd behavior and it is also able to raise the mash pH more than just 0.2-0.3 pH units over the distilled water pH of the grist. I.e. the pH that you would get with very soft water.


Quote
OTOH, if I take a carbonator cap and add my chalk in the PET bottle, throw in some distilled and gas it, the stuff will go into solution?
I take it has nothing to do with the pressure, but rather the formation of carbonic acid in the water?
Presuming I shake the snot out of the PET bottle, how long will this process take?
Please straighten me out here, thanks.

I don't exactly know why dissolved chalk behaves so much different in brewing compared to undissolved chalk. If I test the alkalinity of a dissolved and a suspended chalk solution, of the same chalk concentration, I get the same alkalinity. I.e. the neutralizing power towards an acid is the same.

The dissolved CO2 will form carbonic acid which lowers the pH and converts the carbonate of the chalk to bicarbonate. That makes the chalk much more soluble. If the concentration of chalk that should be dissolved is fairly large, simple atmospheric CO2 pressure is not enough and you need to force carbonate the water. Do that by shaking. Then let it stand and you'll notice that the liquid  starts to clear up. I still have to do some searching for a formula that gives me the minimum CO2 pressure that is needed to dissolve a given concentration of chalk.

If you want to give this a try, I'm glad to help. I also started to test my spreadsheet that allows for grist and water based mash pH prediction. I used it for the Doppelbock I brewed today and the prediction was only off by 0.01 pH units. Now that may have been luck, but for other beers in the past It has been off by less then 0.05 pH units which is the precision I was hoping for.

Kai


Online Kaiser

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Re: undissolved vs. dissolved chalk
« Reply #10 on: November 29, 2009, 10:14:25 PM »
I looked a little further into the CO2 pressure needed to dissolve chalk. I took the data from Wikipedia and plotted it into chart with logarithmic x and y axes. Ther formula that approximates the data well in the range that is of interest for us is

[p in kPa] = 8.71e-8 *  [CaCO3 in ppm]^3.24

This means that there is a dramatic increase of the pressure needed as the concentration of chalk that needs to be dissolved is increased. In practical terms this limits the chalk that can be dissolved by the soda bottle or keg method to about 880 ppm and with it sets a minimum amount of water that is needed to practically dissolve the chalk. I'm adding this calculation to my spreadsheet. To dissolve that concentration of chalk about 3 bar or 45 psi of CO2 are needed. This includes the ambient pressure which means you would have to set your regulator to at least 2 bar or 30 psi.

Here is a chart I made that illustrates the relationship



It also shows the chalk that can be dissolved by the CO2 in ambient air and a pure CO2 environment at atmospheric pressure.

Kai