Author Topic: Palmer Spreadsheet Error  (Read 6630 times)

Offline johnf

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Re: Palmer Spreadsheet Error
« Reply #45 on: December 19, 2010, 09:06:11 AM »
Another alternative to chalk would be the use of calcium hydroxide. Also known as pickling lime it is more soluble and also raises the pH while adding calcium to the mash. I haven't investigated it's behavior in the mash yet.

Kai

Good call. Easier to get and handle than potassium hydroxide, and it adds calcium.

I think I might do an experiment this spring. Brew the same beer back to back and set the mash at the same pH. One with chalk, one with calcium hydroxide. I'm sure both will work but I am interested in flavor differences. I would expect the pickling lime to be neutral and the chalk to have a flavor impact and this might clarify whether or not that flavor impact is positive.

Offline mabrungard

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Re: Palmer Spreadsheet Error
« Reply #46 on: December 19, 2010, 10:41:37 AM »
Slaked lime (aka Pickling Lime) is sometimes used to add alkalinity in drinking water.  In that case, air or CO2 are bubbled through the slaked lime solution to react the excess OH ions back down to HCO3 ions.  As some of you may know, my profession is in water engineering.

But given the fact that our primary concern in mashing dark grains is avoiding an excessive pH drop, we don't necessarily need to convert the acid consuming OH ions into less reactive (but still acid consuming) HCO3 ions.  The only thing with working with the slaked lime is that it will be far less forgiving.  This is just like working with an acid.  You would need to know what you're doing and add exact amounts.  

I'll work through the dosing quantification for slaked lime and get back to folks on this. OH and HCO3 are roughly interchangable as alkalinity producers, its just that OH is not a buffer and will automatically consume acid without moderation.  So there is no leeway.

Lime will get us away from the problem of limited chalk solubility.
« Last Edit: December 19, 2010, 11:34:03 AM by mabrungard »
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Online Kaiser

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Re: Palmer Spreadsheet Error
« Reply #47 on: December 19, 2010, 03:37:44 PM »
In a mash lime should be as forgiving as any other salt because the mash is a strongly buffered system. Adding x ppm of lime will raise the pH by y. And adding 2x will raise it by 2y. The same as baking soda does. This is because the 1 pka (buffer pH point) of carbonate is 6.4 which is sufficiently far enough from our mash pH targets.

Martin, I didn't realize that you are a water engineer. I guess I have to be extra careful about what I'm writing ;)

Kai

Offline mabrungard

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Re: Palmer Spreadsheet Error
« Reply #48 on: December 19, 2010, 03:52:43 PM »
The mash is buffered, but the hydroxide is not.  It will consume any proton available.  This is unlike the alkaline buffer, bicarbonate which doesn't have the power to consume the weaker acids.  Therefore, the pH will rise until all the hydroxide is consumed. 

I don't think it will really make a difference to a brewer who is careful and precise with their mineral and acid additions.  But it could make a difference to the brewer that adds stuff based on the TLAR theory (that looks about right). 
Martin B
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Online Kaiser

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Re: Palmer Spreadsheet Error
« Reply #49 on: December 19, 2010, 04:24:59 PM »
But at a pH of 5.4, 90% of the added HCO3 will neutralize acids. For lime it is 100% of the adden OH. There is not much difference between the two. Do I understand this right or is there something I missed?

Kai

Offline richardt

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Re: Palmer Spreadsheet Error
« Reply #50 on: December 19, 2010, 07:04:35 PM »
This is all very interesting.  Why isn't CaOH used more often in brewing?  Does it cost more?  Does it have unintended consequences when used for mashing or brewing?

If it turns out to work just fine, I sure hope all of you guys who write the spreadsheets (e.g., JP, Kai, EZWaterCalculator, BeerSmith) collaborate with water chemistry experts like AJ and Martin and help advance the predictive accuracy of these spreadsheets by taking into account the amounts of caramel and roasted grains in the gris, and listing the resultant pH and residual alkalinity.

From a practical standpoint, if CaOH does become a useful brew salt addition, then all the spreadsheets (JP's, Kai's, EZWaterCalculator, BeerSmith, etc.) will need to be updated to assist the brewer, and preferably in the most user-friendly manner (i.e., using units like grams, not ppm--although that can be simultaneously shown for those who desire that information).

I just hate making less than great beers because I followed a "spreadsheet."  I did that a while back on an AAA using just BeerSmith and JP's water calculator--I nailed all the ppms for each ion, but the mash pH was well under 5.2.  By then it was too late. 

Offline johnf

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Re: Palmer Spreadsheet Error
« Reply #51 on: December 19, 2010, 07:31:50 PM »
This is all very interesting.  Why isn't CaOH used more often in brewing?  Does it cost more?  Does it have unintended consequences when used for mashing or brewing?


Chalk and pickling lime are both stupidly cheap. Believe it or not the latter is used frequently in brewing to lower the alkalinity in brewing liquor. Yes, I know it is counterintuitive that calcium hydroxide is used to lower alkalinity.

I suppose chalk is used to raise alkalinity because that mirrors what happens in nature. There is no good reason (other than historical authenticity) to duplicate nature though.

Note that raising alkalinity is rarely required. Much more thought has gone into acidification as it needs to be done many times more often than the opposite.

As for unintended consequences, my guess is that calcium hydroxide is relatively flavor neutral. A lot of people believe that the flavor impact of calcium carbonate in dark beers is positive. I'm not convinced (that calcium carbonate has positive flavor impacts beyond downstream effects of pH changes) which is why I want to do a side by side.

Online Kaiser

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Re: Palmer Spreadsheet Error
« Reply #52 on: December 19, 2010, 08:44:29 PM »
Calcium hydroxide is a caustic alkali and needs to be handled with care. I guess that's why it wouldn't be my first choice. Kristin England has talked about using it in the mash before.

Kai

Offline gimmeales

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Re: Palmer Spreadsheet Error
« Reply #53 on: December 20, 2010, 02:42:07 PM »
So, having just started playing with the EZWater calculator, this is a timely discussion.  All the scientific analysis aside, I would like to know practically, if the tool (v2.0) good enough for the homebrewer just beginning to tweak his water?   Sounds like I'm in good shape if I don't add chalk (thankfully, doesn't appear I need to based on my water and desired ion profile for my next few beers).

Appreciate an input!

Offline mabrungard

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Re: Palmer Spreadsheet Error
« Reply #54 on: December 30, 2010, 10:32:59 AM »
The problem with chalk additions in some water programs is that they are calculating the amount of carbonate added to water with the chalk addition.  Since chalk is calcium carbonate, it seems perfectly logical that the carbonate number is the correct one.  Unfortunately, carbonate chemistry is a little more complicated than that.

First of all, in the typical drinking water pH range, carbonate (CO3) will mostly not exist in the water.  It naturally converts to the bicarbonate (HCO3) form in the typical drinking water pH range.  Many of you will recognize that the carbonate species exist in different ionic forms depending upon the pH of the system.  It exists as carbonic acid (H2CO3) at low pH, as bicarbonate (HCO3) at middle pH, and as carbonate (CO3) at high pH.  For the most part, our brewing is in the middle pH range and bicarbonate is prevalent.

The most important reason that we need to convert the carbonate concentration to its equivalent bicarbonate concentration is that the formula that we're using to calculate alkalinity assumes that everything is in the bicarbonate form.  So we have to convert our alkalinity producers to their equivalent bicarbonate concentration.

Since the milliequivalent concentration of the carbonate species will not change when they transform to its various forms, we can calculate what the equivalent amount of each species (in mg/L) is as it transforms and find that numerical conversion value.

Some important chemistry information:

milliequivalents per liter is equal to the ionic concentration divided by the ion's equivalent weight.  

The ion's equivalent weight is equal to the ion's molecular weight divided by the ion's charge.

For Carbonate, the eq wt = 60 mg/mole divided by its charge (-2), or 30 mg/mole
For Bicarbonate, the eq wt = 61 mg/mole divided by its charge (-1), or 61 mg/mole

I'm going to add another alkalinity ion for something else I'll present later.  The equivalent weight of hydroxide (OH) is 17 mg/mole divided by it charge (-1), or 17 mg/mole.

Since the milliequivalents per liter do not change when we convert from one form of carbonate ion to another, we can calculate what that numerical conversion from carbonate to bicarbonate is.  That conversion is simply the ratio of the equivalent weights of the ions.  In the case of carbonate and bicarbonate, that ratio is 61/30 or 2.033333333.  To convert a calculated concentration of carbonate ion to its actual concentration of bicarbonate ion at the typical drinking water pH range would be to multiply the carbonate concentration by 2.033.  

So for a typical 1 gram per gallon chalk addition, the calcium concentration would be 105.7 ppm.  But instead of the 158.4 ppm carbonate concentration, the bicarbonate concentration is actually 322.3 ppm (158.4 x 2.033).  Note that the mEq/L are equal:  158.4/30 = 5.28  and 322.3/61 = 5.28.  

The real problem with chalk is that it just isn't that soluble in water.  There are entire book chapters written on the subject of calcium carbonate solubility since it is critical to life and critical to potable water supply engineers like myself.  

At standard temperature and pressure (STP), the solubility of chalk is about 47 mg/L, which is not that much.  That equates to less than 0.2 grams of chalk in each gallon of water.  Those of you that use chalk know that it just doesn't seem to dissolve in water.  You can bubble air through the water to get it to dissolve faster, but if you're working with air at atmospheric pressure, then you're only going to get that 47 mg/L into the water.  That amount of chalk provides about 55 ppm HCO3 or about 45 ppm alkalinity, which may not be enough for the typical brown or black beer mash.

Work by Troester and DeLange have confirmed that chalk solubility in the mash isn't much higher.  Apparently, the acids present in the mash are pretty weak and cannot provide the protons needed to dissolve the chalk.  It takes extra effort in the form of adding CO2 to the water to get the chalk to dissolve in water.  

I have done tests with water and chalk added at a rate of 2 grams per gallon and have easily dissolved it when I added CO2 to the headspace of the soda bottle and pressurized to over 15 psi with a carbonator cap.  This improves the solubility by over 10 times, but that may not really be practical if your dealing with water needed for a 14 barrel mash.
  
To add alkalinity to mashing water we can also add baking soda (NaHCO3), but then we have to worry about a practical limit for sodium (150ppm, but it should really be kept below 100 ppm).  

So, we need another option to add alkalinity to their mashing water.

Pickling Lime (aka Slaked Lime) is calcium hydroxide (Ca(OH)2).  It is very soluble in water and does not face the solubility problems that chalk has. But I haven't seen anyone discussing how it should be added.

We need to go through the same milliequivalent/liter game that we went through with the carbonate/bicarbonate transformation. The ratio of equivalent weights between bicarbonate and hydroxide is 61/17 = 3.588.  

Therefore, the concentration of calcium added when 1 gram of pickling lime is added to 1 gallon of water is 142.8 ppm and the concentration of hydroxide is 121.1 ppm.  Converting that hydroxide concentration to its equivalent bicarbonate concentration is: 121.1 (ppm OH) x 3.588 = 434.7 ppm.  

As you might expect with a strong base like pickling lime, it has pretty high alkalinity producing potential.  When its added in the small amounts needed to control mash pH, it doesn't really convert into bicarbonate in the mash.  It just consumes any acid it comes in contact with, converting those OH ions directly into H2O when an acid (H) is encountered.  Since Alkalinity is defined as the measure of the capacity of a water to neutralize strong acid, it doesn't matter that the alkalinity is from carbonate, bicarbonate, or hydroxide.  But since our brewing chemistry analyses are based alkalinity calculated from bicarbonate content, it is important to perform the conversion of hydroxide to its equivalent bicarbonate concentration.  

Since the issue of errors in some water calculation programs was the genesis of this discussion, I should end with its discussion.  Those programs assume the carbonate concentration can be treated as a reduced concentration of bicarbonate.  Considering the limited solubility of chalk, its not a bad assumption.  Unfortunately, the severely limited solubility of chalk make even that assumption to optimistic unless the brewer is going to dissolve the necessary quantity of chalk under CO2 pressurization.  In addition, if the brewer does actually use CO2 to dissolve the chalk in the water, then the alkalinity calculated for the chalk addition would definitely be wrong with those water calculation programs. The real solution to adding alkalinity (without too much sodium) is to get brewers up to speed with using pickling lime for adding mash alkalinity and forget about chalk.

I trust this information will be helpful.    
« Last Edit: December 30, 2010, 10:43:07 AM by mabrungard »
Martin B
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Online Kaiser

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Re: Palmer Spreadsheet Error
« Reply #55 on: December 30, 2010, 03:30:14 PM »
Martin,

Thanks for taking the time to look into this again.

But what I still don't understand is how the mash can be at a pH of 5.4 while the chalk does not dissolve? If I make suspended chalk water and add a weak acid like lactic acid to keep the pH around 5.4 the chalk will slowly dissolve.

Also, why does only half of the chalk dissolve and why is there a saturation at which additional chalk won't raise the mash pH further?

These are questions that I have been thinking about for a while.

Kai

Offline richardt

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Re: Palmer Spreadsheet Error
« Reply #56 on: December 30, 2010, 06:23:44 PM »
I just brewed by BDS on the 28th using Sean's suggested salt additions (16 gallons RO water plus 4 gms each of CaCl, NaCl, and MgSO4, plus 8 gms of Chalk, and 16 gms of Baking soda).  My pH readings were around 5.0 with all the CaCl, NaCl and MgSO4 plus half the chalk and baking soda as initially recommended (it was 5.3, but, with additional stirring and time, it drifted back down to 5.0), and at 5.1-5.2 with the full additions. Yes, these are cooled sample temps (it was 50 F outside that day).   I hoping this beer tastes great!

Kai and Martin raise great points for further discussion.  Based on the prior post, I would have expected to observe a pH of 5.5, let's say, at ambient temps around 50-60 F (and not the pH of 5.1 - 5.2 that I got.)  Martin may be onto something here.  Just wanted to provide feedback on the recommendations given to me via the forum.  Thanks everyone.

Online Kaiser

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Re: Palmer Spreadsheet Error
« Reply #57 on: January 03, 2011, 10:22:08 AM »
I finally got around to testing the use of slaked lime (Ca(OH)2) and lye (NaOH) for mash pH adjustments. Lye behaved as expected. The slaked lime did better than chalk and it doesn’t seem to show the saturation that chalk additions tend to show. The pH slope for the slaked lime addition depends on the alkalinity neutralizing power that is assumed for the calcium. In the chart below I assumed that each mole of calcium neutralize 1/3.5 alkalinity equivalents. I.e. one mole of Ca(OH)2 adds  2-(1/3.5) Eq of residual alkalinity. The 3.5 comes from Kolbach’s residual alkalinity formula and may not necessarily correct in all cases.



Each series evaluated 2 mash thicknesses (2.5 and 5 l/kg) and the base additions were based on the grist weight (mEq/kg). I think the latter is a better way to think about any water treatments in the mash since the grain is the pH buffer and not the water.  The starting mash was RO water with a 90/10 mix of Munich II and CaraAroma. Not necessarily something that you would make into a beer but a somewhat realistic grist that is expected to give a fairly low mash pH.

There were some hick-ups in the Ca(OH)2 curves that are not visible in the NaOH data. But at this point it is possible that this is simply an error in the measurements.

Looks like a side-by-side experiment and spreadsheet support for Ca(OH)2 additions is in order.

Kai
« Last Edit: January 03, 2011, 10:27:12 AM by Kaiser »

Offline mabrungard

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Re: Palmer Spreadsheet Error
« Reply #58 on: January 03, 2011, 10:29:44 AM »
Excellent information!

Not a surprising result.  I'm cautious about adding lye, since it could boost the sodium content too high.  But on second thought, the amount added for pH adjustment would be tiny.  The next question is where would you get food grade lye from?  I know I can get food grade lime as pickling lime. 

Very interesting.
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Offline denny

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Re: Palmer Spreadsheet Error
« Reply #59 on: January 03, 2011, 10:33:57 AM »
Martin, I've been looking for pickling lime with no luck.  Where do you get it?  A grocery store?  That's where I've been looking.
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