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NanoMan 01-17-2013 10:58 PM

Recipe calls for water hardness
 
This is a question of water hardness. My understanding is that water hardness is largely determined by the ppm of Ca++, and to a lesser degree, Mg++. So if a recipe calls for setting brewing water to a hardness of 100 ppm, are they essentiall saying set the Ca++ to 100 ppm?


NanoMan

Hermit 01-18-2013 12:26 AM

My guess, and it is just a guess, is they would mean total hardness.

I got this recently to at least get me started.
http://www.apifishcare.com/products/product.aspx?productid=74
The "G" would be for general hardness.

ajdelange 01-18-2013 12:48 PM

Total hardness is the sum of the calcium and magnesium hardnesses. When someone says the water has a hardness of 100 they haven't told you the whole story as that could mean calcium hardness of 1 and magnesium hardness of 99 or magensium hardness of 1 and calcium hardness of 99 or anything in between. If you are trying to replicate a recipe that says 'hardness 100', which recipe I would be suspicious of because of this very uncertainty, I would use 40 mg/L Ca++ (equivalent to 100 ppm hardness) because calcium is twice as effective at lowering mash pH as magnesium and magnesium doesn't taste very good.

mabrungard 01-18-2013 12:50 PM

That is a dumb way to describe the water quality needed for a recipe. But, I would say that they may be referring to hardness as CaCO3. If you assume that all of that hardness is due to calcium, the calcium concentration is 40 ppm. That is just barely adequate for normal brewing conditions, but you can brew with it.

Now if the recipe had called out a particular Residual Alkalinity for the brewing water, that could be OK and would be more descriptive. Unfortunately, even that description is not definite and can be produced with a wide range of hardness and alkalinity. A recommendation for RA of your brewing water is still kind of stupid, but it would more likely lead to an appropriate mash pH. To illustrate how dumb this is, look at Pilsen and Burton water. Both have RA's of approximately zero. But the level of mineralization will greatly affect the finished beers. Make an IPA with Pilsen water and its nowhere near as bold as expected. Make a Pilsner with Burton water and you wouldn't recognize it.

A wiser recipe description for recommended water conditions would be to provide approximate concentrations for each of the 6 major ions we are interested in for brewing.

ajdelange 01-18-2013 01:51 PM

Quote:

Originally Posted by mabrungard (Post 4798712)
A wiser recipe description for recommended water conditions would be to provide approximate concentrations for each of the 6 major ions we are interested in for brewing.

That jogs a memory: I used to include chlorine/chloramine on the list and refer to them as The Significant Seven.

NanoMan 01-18-2013 05:48 PM

Thanks for the info. I am hesitant to speak to the merit of this approach in setting brewing liqour as it is the method Mitch Steele of Stone Brewing Co. is using for his recipes in his new IPA book.

AJ Delange, can you explain a bit how 40 mg/L Ca++ is equivalent to 100 ppm hardness?

Cheers!

mabrungard 01-18-2013 06:34 PM

Quote:

Originally Posted by NanoMan (Post 4799747)
Thanks for the info. I am hesitant to speak to the merit of this approach in setting brewing liqour as it is the method Mitch Steele of Stone Brewing Co. is using for his recipes in his new IPA book.

Ahh! I see.

Well, Mitch is a former Anheuser Busch brewer and that is probably a way they taught him. Of course when brewing mega lager, those other ions are typically low and are never increased for brewing. The ions they care about are calcium and bicarbonate. As long as the rest of them are low, its good brewing water for them. Its interesting that he uses 100 ppm hardness as his criterion. I had come to a similar conclusion that 40 ppm calcium was the minimum desirable concentration in brewing water for oxalate precipitation and yeast health.

Hardness is still not a very useful descriptor of water requirements for brewing, though.

ajdelange 01-18-2013 07:01 PM

Quote:

Originally Posted by NanoMan (Post 4799747)
AJ Delange, can you explain a bit how 40 mg/L Ca++ is equivalent to 100 ppm hardness?

100 ppm means that there are 2 milliequivalents of charge per liter. Thus each 50 ppm as Calcium Carbonate is eqivalent to 2 milliequavalents per liter. An equivalent is Avogadro's number of electrical charges. Twenty milligrams of calcium carries 1 mEq of charge. Thus the 'equivalent weight' of calcium is 20 g/equivalent or 20 mg/mEq. For magnesium it is 12.15 mg/mEq. In measuring alkalinity we measure the number of milliequivalents of acid required to neutralize all the carbonate and bicarbonate. By doing everything in mEq/L we can compare the effects of calcium, magnesium and bicarbonate/carbonate in the same units. In Europe they do this. In the US we observe that if 100 mg of calcium carbonate (1 millimole) is dissolved in water using carbonic acid in imitation of the way limestone gets dissolved in nature, there will be 2 millimoles of positive charge on the calcium ions and 2 on bicarbonate ions. Thus we can put everything in terms of calcium carbonate by saying that 100/2 = 50 mg/L calcium carbonate is equivalent to 2 mEq.

Thus, anytime you see 'as calcium carbonate' divide by 50 to get milliequivalents and then multiply by the equivalent weight of whatever it is you are interested in to get mg.

NanoMan 01-18-2013 07:31 PM

Time to dust off my inorganic chem books. Better get a beer first....

Cheers!

ajdelange 01-18-2013 09:42 PM

The stuff about equivalent weights you will find in any beginning chem book. The 'as CaCO3' is a peculiarity of the US water industry (just as the as CaO is a peculiarity of the German....).


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