Tuesday, 9 July 2013

German brewing waters

I'd been meaning to write about this for a while, but was delayed, as usual, by my sloth. I wanted to make a comparison with British brewing waters and that required effort. First, to find the right analyses and second to translate the units of measurement. All the British ones are in the very non-SI grains per gallon format.

The quotes are, once again, taken from Ludwig Narziss's article on the Reinheitsgebot.

First the Reinheitsgebot rules about water treatment. Once again it has me scratching my head wondering why some treatments are allowed and others not.

"3.1.3. The brewing liquor, according to the Beer Law, includes every water to be found in nature. A pretreatment for the elimination of iron, of suspended particles or colloids by precipitation and filtration is allowed as is the addition of calcium sulphate and calcium chloride provided that the water does not have a different composition to natural waters. In particular, the neutral reaction must not be changed or varied. The salts mentioned must be added to the water, not to the mash or to the wort. The addition of any inorganic or organic acid is prohibited. Usually the liquor is decarbonated, i.e. the hydrogen carbonates of calcium and magnesium are removed by saturated lime water, but the added calcium-oxide is quantitatively removed. Weak acid ion-exchangers are used too, but the released CO2 must be removed by rinsing and neutralisation by lime water or marble stones. Strong acid exchangers set free the strong mineral acids derived from the corresponding salts. They are neutralised either by lime water — producing the calcium salts of these acids or by anion exchangers which demineralize the water totally. By blending with the original water, the desired water quality is built up. A similar water composition is attained by electro osmosis, reverse osmosis or electro dialysis. The material of the exchangers as well as that of the membranes and nodules must be of food standard.

Materials using this wide field of procedures it is feasible to produce any conceivable water composition. The addition of gypsum is, with or without boiling of the water, the oldest method to equalise the pH-increasing effect of the hydrogen-carbonate. It seems to be one of the benefits of the visit of the two brewers Anton Dreher and Gabriel Sedlmayer to Burton on Trent and the method was called 'Burtonizing' for almost a century.

The addition of acids is thus prohibited, as the balance calcium oxide-carbon dioxide would be varied. It is possible however, to correct the pH of mash or wort by the lactic acid bacteria of acid malt or by the multiplication of those bacteria in wort. This method is used for some of the most respectable beers in Germany, it is not too popular as the bacteria (long rods) which are killed by hops and wort boiling are still present in the beer and are difficult to distinguish from living organisms. A survey on some types of brewing liquors is shown in Table III."
Journal of the Institute of Brewing, Volume 90, Issue 6, November-December 1984, page 353.

TABLE III. Analytical data of various brewing liquors
Munich Dortmund Munich
Type Original Decarbonated Pilsen Original Decarbonated Decarbonated +20g/Hl CASO4
Total hardness °G 14.8 3.9 1.6 41.3 26.0 9.1
Carbonate hardness 14.2 3.3 1.3 16.8 1.5 1.5
Non carbon-hardness 0.6 0.6 0.3 24.5 24.5 7.6
Calcium-hardness °G 10.6 1.5 1.0 36.7 21.4 6.7
Magnesium-hardness 4.2 2.4 0.6 4.6 4.6 2.4
Residual alcalinity °G 10.6 2.5 0.9 5.7 -5.3 -0.8
SO4 2- mg/l 9.0 9.0 5.2 290 290 180
Cl- mg/l 1.6 1.6 5.0 107 107 1.6
NO3- mg/l Trace Trace Trace Trace Trace Trace

So you can add calcium sulphate and calcium chloride as long as the result is like some water somewhere in the world. I wonder if the Dead Sea and other salt lakes count? They have pretty extreme mineral contents. Not sure they'd be much use for brewing, mind.

I'm so glad Dreher and Sedlmayer get a mention. But I don't believe for a minute that they brought back burtonisation from their trip to Britain. They were there far too early - the 1830's - before the practice had been worked out. I don't think they started burtonising until the 1860's. In any case, Burton brewers had no need to burtonise. Their well water was that way naturally.

I'm struggling to understand why the Reinheitsgebot allows the addition of salts to brewing water but not acids. If I had a brewery, I wouldn't want to deliberately introduce lactic acid bacteria into it. Asking for trouble.

It's time now for the table of British brewing waters. As I don't understand the units being used to measure hardness in the German table, I haven't been able to find similar figures for British waters. In fact, only three entries do match: Cl, SO4 and NO3.

British brewing waters mg/l
Deep Well Waters
highest lowest Old London well water London Metropolitan Water Board supply.
Total solids (dried) 2280.6 1225.8 461.8 319.3
Sodium—Na 51.3 29.9 98.4 24.2
Calcium—Ca 513.1 270.8 49.9 89.8
Magnesium—Mg 81.2 61.3 18.5 4.3
Nitrate—NO3 42.8 31.4 2.9
Chloride—Cl 67.0 35.6 59.9 18.5
Sulphate—S04 1297.1 655.7 77.0 58.4
Carbonate—CO3 1396.9 139.7 155.4 122.6
"Brewing Theory and Practice" by E.J. Jeffery, 1956, page 101.

Unsurprisingly, the SO4 content is highest in the Burton waters. Though the level in Dortmund water is considerably higher than all the other waters. The Cl content of Dortmund water is also high, even higher than in Burton. NO3, which is only present as a trace in the German waters, is found in considerable quantities in the Burton waters.

But what really stands out is just how soft Pilsen water is. With bugger all of any mineral in it.


Matt said...

Have you seen this article about the threat to German brewing water from fracking?

Ron Pattinson said...

Matt, I'd heard German brewers weren't happy, but I hadn't seen the article before. Thanks.

Jeff Renner said...

Image of the first table, please?

Jeff Alworth said...

I wouldn't mind seeing analyses for Dusseldorf and Cologne. What I took away was the importance of the mineral quality of the local waters on kolsches and especially alts. I've never tasted an American-brewed alt that was an authentic facsimile because the quality of the water never quite matched.