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Old 01-28-2012, 12:39 AM   #1
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Default Brewing with Low Alkalinity Water

RO, distilled, and rain water are examples of low alkalinity water. Brewing with low alkalinity water is almost always a desirable thing. But, there are some mash grists that demand a little more alkalinity to keep the mash pH from dropping too low. Increasing percentages of roasted and crystal malt and grain make it more likely that alkalinity will be needed to moderate those more acidic grains.

An option for reducing the impact of those acidic grains in the mash is to steep them separately or add them at the latter part of the mash. These are workable alternatives.

Adding alkalinity to mash water can be problematic. Chalk is an unreliable alkalinity provider since you have to properly dissolve it with an acid to achieve its full alkalinity potential. Baking soda use is limited by the fact that you're adding sodium to your water and there are definite flavor impacts when added in excess. Pickling lime is a good alternative in that it adds calcium and dissolves fully, but it is a strong caustic and demands careful measurement and dosing.

It has come to my attention that there may be another option for reducing the need for alkalinity in mashing. We know that adding calcium and magnesium to the mash decreases the Relative Alkalinity (RA) of the mash water. We also know that we want a minimum concentration of calcium in our wort to promote yeast health and beer clarification.

My suggestion is that in the case of mashing with low alkalinity water, reserve any calcium or magnesium salt addition from the mash and add that directly to the kettle. In this way, the alkalinity deficiency of the mash water is not made worse by adding those salts to the mash.

This is especially true when working with a highly mineralized water profiles like Burton, Dortmond, or a Pale Ale water. For those waters, the desired sulfate or chloride concentration is often added with calcium or magnesium cations. These water profiles end up needing more alkalinity due to the elevated Ca and/or Mg and the resulting reduction in RA.

So when a program like Bru'n Water indicates that more alkalinity is probably going to be needed, try a recalculation of the mash pH by taking out the calcium and magnesium salt additions. If the mash pH prediction increases into a more desirable range, just reserve those original Ca and Mg mineral additions from the mash and put them directly into the kettle when you boil.

Enjoy!



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Old 01-28-2012, 08:27 PM   #2
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A thought provoking post. Here are a couple of the thoughts (not, for the most part new).

It is quite possible to dissolve chalk in water by following mother nature's way and thus achieve the full alkalinity potential of the salt. The simplest method is to suspend the desired amount of calcium carbonate in the water, use a pump or stirrer to keep it in suspension and bubble CO2 through it until the water turns clear and the pH reaches a reasonable value (less than 8.3). This method takes a long time (a day or more) and, thus, uses a lot of CO2. Calculation of the amount of calcium hardness and alkalinity is trivial if you do this and keep the pH close to 8.3. It's 1 mg/L calcium hardness and 1 mg/L alkalinity for each mg/L of chalk added.

The process can be accelerated if the partial pressure of CO2 is increased as by putting water and chalk in a Cornelius keg under a couple of atmospheres CO2 pressure and shaking. The chalk will dissolve much faster. The calcium bicarbonate solution thus prepared is added to the water being treated but this must be done quickly as the calcium bicarbonate solution is super saturated both WRT CO2 and CaCO3. Over time CO2 will come out (in bubbles if enough pressure was applied) and chalk will precipitate. Again calculation of the added calcium hardness in simple and depends on the amount of CaCO3 effectively added (e.g. if you put 200 mg CaCO3 into 4 liters of water and dissolve and then add 2 of those liters to your water you have effectively added 100 mg/L) CaCO3 to your water, the final volume and the pH of the final (mixed) volume. As I have given the formula in at least 2 recent posts, I will not repeat it here.

If time is not of the essence you can suspend CaCO3 in water and bubble air through it. Air contains a wee bit of CO2 and will dissolve chalk to the extent of 50 ppm as CaCO3 alkalinity. In this case, an excess of chalk is suspended and it will not all dissolve. The idea is to get the system into equilibrium. In a system in equilibrium with CO2 and CaCO3 the alkalinity, pH and hardness are controlled by the partial pressure of CO2. Increasing that will increase the amount of alkalinity and hardness. If, for example, 25% beer mix were bubbled through and the container covered so that the gas over the liquid is in equilibrium with the beer mix, we would obtain 561 ppm alkalinity and 568 ppm calcium hardness (both as CaCO3) at 20 °C. Just by increasing the temperature to 40 °C that can be reduced to 395 ppm alkalinity and 400 ppm hardness.

So it's possible to control akalinity to almost any level desired but the nagging question is "Is it worth it?" That, of course, depends on why you are doing it. If you are brewing a dark beer with available low alkalinity water and the pH goes low then you need to raise it. It seems, in such a case, much simpler to add some calcium carbonate to the mash (or some other salt or base) than to go through the elaborate procedure with CO2.

Now here I'll wax philosophical. You need base because you need to neutralize the acid from dark malts which the original brewer of the style had to use to neutralize base in his water. Therefore, you shouldn't need to add more base than was in the original water. Water at equilibrium with the CO2 in air and chalk will be at about 50 ppm as CaCO3. Surface water usually is not higher in alkalinity than 80 - 100. Waters of higher alkalinity probably came from wells the point being that these waters were likely supersaturated (CO2 and CaCO3). If this was, indeed, the case, then as soon as the water was heated chalk would drop and the alkalinity would go down. I can attest from personal experience that if I go to the trouble to prepare Burton synthetic water using the CO2 method that this is the case as soon as the heat is turned on in the HLT. OTOH chalk is not dropped when water of alkalinity and hardness of under 100 are heated (unless nucleation sites and excess calcium are added). So the straw man thesis here is that no beer that evolved into a style that survived was brewed with water more alkaline than about 100 and that, therefore, no more than 2 mEq/L acid from dark malts was ever used to combat it and that, therefore, you should never need more than 2 mEq/L base in brewing a dark beer whose dark malt component is based on a traditional style. A related statement is that it isn't sufficient to know what (e.g) Burton water is like but that one must know how the brewers at Burton treated it. If they doughed in cold, the alkali would precipitate out in the mash. If they heated the water first it would be left behind in the HLT. I'm guessing it was the latter but I am guessing. It is a waste of time to add the minerals necessary to provide the alkalinity of Burton water as they are coming back out as soon as the water (or mash made with it) is heated. What I'm coming to is that I suspect that if you require more than 2 mEq/L alkalinity you are using more dark malt than you should if you are trying to emulate one of the common styles. That much alkalinity can be had from 2 mmol/L NaHCO3 which would contribute 44 mg/L sodium. Not too much except in cases where the base water is already high in sodium. In fact I suspect that if you need more than 1 mEq/L you are using too much dark malt. This conclusion is bolstered by the results of my own brewing in which even fairly dark beers (most recently a barley wine at 30.7 SRM and a stout at about 70) require acid when using water with alkalinity below 1 mEq/L.

Now if you wanted to brew beer near Wadi El Natrun (or some other alkali flat) you would have much higher alkalinities than 2 mEq/L to deal with and much more dark malt would be required to deal with it. But AFAIK no style we emulate today originated in a place like Wadi El Natrun (yes, Stella is bad beer but not that bad). But as a home brewer you are, of course, free to do anything you like e.g. brew an Irish stout with 40% roast barley instead of the traditional 10%. In such a case you would need lots more alkalinity than normal and in such a case I think you will just have to bite the bullet and add alkali. Calcium carbonate is problematical because it reacts slowly - not because it is a weak base. It is, technically, a weaker base relative to calcium hydroxide or lye or potassium hydroxide but with respect to bringing mash pH to 5.4 or thereabouts each adds the same number of mEq alkalinity per mEq of the base added (slightly less for bicarb/carb but only a few %).

Finally, WRT witholding calcium - yes, should work but calcium is not that powerful an acidifying agent. 100 mg/L calcium only swings pH 0.12 units. In addition to which WRT the Burton example I strongly suspect that the calcium level that went into the mash tun was not more than about 1 mEq/L because of precipitation.



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Old 02-02-2012, 06:35 AM   #3
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I have NaOH on hand for making lye dipped pretzels. My past 2 mashes I've adjusted my PH up with it. The first time I used 1/4 tsp in my 5 gallon batch and it was a much larger jump than I expected. The second time I just added an eighth at a time till my PH was where it needed to be.

It's not a practical solution for most people, but I had the stuff on hand and am familiar with handling it so it worked nicely for me.

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Old 03-02-2012, 04:13 PM   #4
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I went down the same road of removing calcium from the mash, but you actually still want around 50 PPM in the mash itself for alpha-amylase stability and mash efficiency, so if you have too little calcium, you're also causing problems for yourself.

I'm going to try calcium hydroxide (pickling lime) in my next batch.

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Old 03-02-2012, 06:56 PM   #5
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thegerm and Hop: when you need to increase pH what styles of beer are you brewing, what's the water like and how are you measuring pH.

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Old 03-02-2012, 08:20 PM   #6
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ajdelange:

My water is very soft. It measures at ~5.5 pH with colorpHast strips at room temperature. If Braukaiser is correct that those strips have a systematic error of 0.3, my water starts at 5.8 pH. I've measured with two other (cheaper) strips with pretty much the same results. My terrible mash efficiency since starting to use this water at my new house would indicate that the pH is correct.

If I brew anything above ~12-14 SRM, I have to start adding quite a bit of calcium bicarbonate and sodium bicarbonate to get the pH up to 5.2.

It's been plaguing me ever since I moved to Rhode Island (I've been brewing for over a decade and this is the first time I've had low pH problems with anything below ~25-30 SRM).

I've started steeping virtually all 100+ Lovibond grains and put almost exactly 50 PPM Calcium in the mash to mitigate acidification.

Even doing this, my pH needs to be at least adjusted with chalk/baking soda, and I get to a point at which I become uncomfortable adding more salt.

Hence the desire to try something more extreme like adding calcium hydroxide.

Any other suggestions are more than welcome because I'm all out of ideas.

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Old 03-02-2012, 09:03 PM   #7
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I rather suspected this would be the response. In Kai's experiments the strips he tested showed a bias of about 0.3 but I've seen others post discrepancies between strip readings and pH meter readings larger than that. Always low.

The only clue I've got as to what is happening is that a gentleman here posted a picture of the strip he had immersed in wort and the bottle with the legend. The color of any pixel is easily measured on a Mac (and probably also a PC) and so I thought I could measure his test strip, interpolate between patch colors and come up with a more accurate pH estimate (I'm color blind so this is my only option). What I found was that the color of his test strip did not lie between the colors of the swatches on the legend. Little surprise, therefore, that we can't read pH with these. Strips stained with wort appear to lie in a different part of the color space than the legend.

In any event I am guessing that if you obtain a pH meter and use it to check mash you will find that you do not need to add alkali except for very dark beers. The strips have lead more than just you down this path.

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Old 03-02-2012, 09:30 PM   #8
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Hop: I'm sorry that you're having that much trouble. As AJ says, you don't want to add any more alkalinity than necessary and you're trying to follow that advice. But your measurement method might be letting you down.

Do you know your water profile and have you tried a program like Bru'n Water? That will get you in the ballpark if you are weighing your mineral additions carefully. A program like that might be a better alternative to pH strips, but a calibrated pH meter is the best check.

I do like the option of reserving your roasted grain to keep the pH up. It works well. You can also consider reserving the crystal malts too if the pH is not meeting your target. Right now, I'd say that the strips might not be giving you good information and that is going to be an impediment.

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Old 03-05-2012, 04:31 PM   #9
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The water pH as reported by my local water supplier is actually 5.7, which corroborates what I see when measuring tap water at room temperature (a colorpHast measurement of ~5.5 + 0.3 systematic error). My water is very soft (everything in it is quite low) with a crazy low pH and alkalinity listed as 12 mg/l.

I'm pretty sure all of this madness is reality.

I've used the same strips for years and only started having the low pH numbers after moving to Rhode Island less than a year ago.

I tried just letting it sit or adding a few salts for alkalinity and the pH always read low and efficiency was terrible. I upped the salts considerably and the pH got a little higher (as did efficiency), but it's still too low (mash efficiency is still below 70% and I used to hit closer to 80% with my other water).

That's why I'm now looking for more extreme solutions like calcium hydroxide.

I brewed a 14 SRM beer and got bad efficiency and low pH readings with 1 tsp of calcium carbonate and 1 tsp of sodium bicarbonate. It's insane! I also brewed a 28 SRM beer with similar results (and needed more brewing salts for the same fairly poor results).

I thought perhaps my thermometer was off in addition to the pH strips being utterly incorrect (to account for the poor efficiency), but it is still properly calibrated (212 at boiling in water, plus it is within a couple of degrees of some other thermometers I had lying around).

I've been building my water (started doing this a couple years ago) with a modified version of Palmer spreadsheet (using some things from Braukaiser and some from Bru'n Water).

At this point, I really do want to send in a sample of my water just for a final stamp from Ward Labs (when the wife lets me spend the money), but I've used nearby water reports from other homebrewers as well as data from the local water authority (and my own pH measurements and mash observations) to arrive where I am now.

My real questions at this point are:
- Will calcium hydroxide impact the flavor or otherwise negatively affect the final beer?
- How much do I need to raise the pH by some number of points (that I can use as the basis for calculations. e.g. if 1/8 tsp raises it by something crazy like 1.0 pH, that'll be useful to know beforehand so I don't overcompensate by accident)

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Last edited by Hop; 03-05-2012 at 04:37 PM. Reason: Added some clarification
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Old 03-05-2012, 04:51 PM   #10
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Calcium hydroxide (pickling lime) is a pretty strong base and I'm very cautious in its addition. You mention teaspoon measurement and this is a chemical that this sort of measurement is not good for. The amount you might need is typically very small and under that condition, a volumetric measure could easily miss the mark. I strongly recommend using a scale that can read down to the tenths of a gram. In 5 gal of RO mash water for my batches, I might add less than a gram of lime and its a teeny amount of that powder. The exact amount varies in accordance with the grist. It would be so easy to screw that up with a teaspoon and the degree its packed (or not packed) into the spoon.

From my experience, I don't think that lime affects flavor (assuming its not overdosed). Calcium is relatively flavorless and hydroxide is flavorless. If the wort pH is overly low, the lime addition should be flavor beneficial in that the tart edge would be taken off the beer. Just be very careful, its better to have a little too low a pH than too high.

Bru'n Water has a calculation built in for using Lime. Its all based on the total acidity added by the grist and the total alkalinity added by the water. That balance is what drives mash pH.



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