Showing posts with label Dortmund. Show all posts
Showing posts with label Dortmund. Show all posts

Thursday, 20 July 2017

Dortmunder Versandbier

An old German beer style, but not a top-fermenter. No, this a description of a classic Lager style: Dortmunder Export.

The type of beer which for a big chunk of the 20th century was the most popular in Germany. Until Pils came along and unseated it from its perch. Export has faced very hard times since. Brewery closures meaning Dortmund no longer produces more beer than any other town in Germany.

Things were very different back in the 1920’s, when Dortmunder Export was both well-regarded and popular. That’s when this description was written.

Our tastiest, but also the strongest characterful, pale beers are the original Dortmunder Versandbiers.

It’s brewed using a highly-dried, but still, pale malt.

Usually a two thick mash method is used, but sometimes also two thick mashes and one lauter mash.

With regard to maintaining a pale colour the first method is recommended and the mashes are only boiled for 10 and 5 minutes. By boiling the malt husks, which have a raw, harsh flavour, for too long the fine, spicy flavour is considerably diminished.

Mashing in is at 35º C, rising to 55º Cand then to 70º C. Where care is taken that full saccharification takes place. Then the wort is boiled for 5 to 10 minutes and combined with the rest of the wort to mash out at 70º C. Later, with the second thick mash, it’s mashed out at 75º C.

In a three-mash scheme, the temperature of the combined mash is brought up to 55º C with the first thick mash, 70º C with the second thick mash and 75º C with the lauter mash.

In order to keep the noble flavour the mash shouldn’t be too thick and should be quickly run off while the temperature is maintained at 75º C; stir the mash only once or twice. During sparging the temperature in the tun should be maintained at 70º C. Boiling the wort should only begin when the second sparge is running, and should last at least one hour.

The hopping rate is 1.3 pounds per 50 kg of malt, depending on the quality of the hops. Only the highest quality hops should be used, with a third added when the copper is filled, another third after an hour of boiling and the final third 45 minutes before the end of boiling. Total boil time should be a maximum of 2 hours.

The OG for Exportbier is 14º Balling.

The wort is pitched with a pure culture of Dortmunder yeast at 5º C, rising to 8.5º C. The wort is then cooled back down to 5 to 4º C.

Primary fermentation lasts 3 to 3 weeks. So that the beer stays sound for a long time a very high degree of attenuation is sought, so it’s logical that a highly-attenuative strain of yeast is used. These beers, which are lagered under pressure at 1º C for a long time, are very highly carbonated and full and elegant tasting.
Source: Olberg, Johannes (1927) Dortmunder Versandbier in Moderne Braumethoden, pp 66-67, A. Hartleben, Wien & Leipzig.

That’s a fairly detailed set of brewing instructions. Should be able to knock together a recipe from that. Though my biggest problem would be choosing the malt. Is pale malt more highly-dried than pilsner malt? In which case that, oddly enough, might be the best equivalent.

Tuesday, 7 October 2014

German brewing in 1960

Right. More Lager. I seem to have gone back into bottom-fermenting mode. No idea why. Just interesting stuff I tripped over, I suppose.

This is the second part of a Journal of the Institute of Brewing article on Danish and German brewing. We'll dive right in with the introduction.

"West Germany
In West Germany, beer is subject to the Purity Law which forbids the brewing of beer from materials other than malt, hops, yeast and water. This restricts brewing to all-malt mashes and prohibits the use of soluble chill-proofing agents. Adsorptive materials have, however, long been allowed, and where formerly beech shavings were added to the lager cask, silicate earths such as bentonite are now widely used for clarification.

Great changes have been made in the last 15 years with rebuilding, particularly in the war-damaged areas of the North which now holds a distinct technical lead in modern plant over the old-established centre of Munich. With the growing popularity of pale Dortmund beers, there are now, in Dortmund, the four largest single German breweries with a combined output of over 2.5 million brl.; this represents about 8.2% of the total German beer production."
Journal of the Institute of Brewing, Volume 66, 1960, pages 498 - 499.

He's not quite correct there with the Reinheitsgebot - it allows sugar in top-fermenting beer. I like the mention of beechwood shavings, a practice I seem to remember an obscure American brewery employing. I know what the argument is for allowing things like shavings and silicate earth: they didn't end up in the finished beer, ergo weren't ingredients. It's a bit of a fiddle.

Interesting that the focus of the industry was moving north from Munich to the Rhineland. Though I guess I should have known that, as Dortmunder Export was all the rage after WW II. That growing popularity was just about to end, as this table shows:

German beer production by beer type (%)
type 1968 1970 1976 1992
Export 57% 50% 32% 10.1%
Pils 19% 25% 41% 64.1%
Sources:
Die Biere Deutschlands, 1993.
Brauwelt Brevier 2003

2.5 million barrels isn't a great amount for the four largest breweries in the country. That's only an average of 600,000 barrels each. It shows how much less concentrated the German brewing industry was than the British one. The largest British breweries in the late 19th century brewed over 1 million barrels a year. The four largest UK breweries would have produced way more beer than that in 1960. 

Now something on beer types:

"In general, beers fell into three types: the dry, highly-hopped Pilsner, the fuller and less bitter Dortmund and Bavarian voll-bier type, and the heavy dark Munich type. Barleys were obtained from Central Germany and Czechoslovakia, and those from the latter source, being generally finer in quality and of lower nitrogen content, were used extensively for Pilsner brewing. Australian barley was also bought direct ex-farm at competitive prices, but extensive screening was needed before it could be used."
Journal of the Institute of Brewing, Volume 66, 1960, page 499.

It's indicative of how marginal Weissbier was at the time that it doesn't even get a mention. By Bavarian Voll-Bier they mean Helles and "the heavy dark Munich type" is Dunkles. Which was already starting to become rarer. As this table demonstrates:

Löwenbräu Munich sales by type %
1938/39 1950/51 1960/61 1970
Dunkles 64 17 11
Helles 36 83 89
draught 80 56 41 37
bottled 20 44 59 63
Source:
"Löwenbräu, Von den Anfängen des Müunchner Brauwesen" by Wolfgang Behringer, pages 268 - 269.

And that's a brewery in Munich, a place where Dunkles remained relatively popular. Be interested to know what the proportion of Helles and Dunkles is today.

Not having seen German brewing logs, I didn't really have idea of the source of their barley. Czechoslvakia is pretty obvious, other than the Iron Curtain thing going on at the time. But I wouldn't have guessed Australia. Obviously Britain, with its global Empire and international trade plucked raw materials from every part of the world.

Now let's look at German malting:

"Malting.—The main malting procedures observed are outlined in Table III. Aeration in steep was always abundant and was usually in-place, but occasionally involved transferring to another cistern. All six makings visited had modern Saladin installations, although Munich and Märtzen malts were still made on the open floor.

Kilning provided many examples of modern plant operated with much reduced labour forces. A common feature was the singlefloor construction with forced air draught provided from a pressure heating chamber below, with turning in this case unnecessary. Quantities of the order of 100 Qr. were kilned at one time, with a limiting depth of about 30 in. Heat supply to the calorifier was either steam or super-heated water in a closed high-pressure circuit at temperatures well above boiling point. Temperature-recording at various points in the piece was common, and in one plant the rate of ventilation was electrically coupled to the relative humidity of the exhaust air. Some kilns could be tilted for discharge; others used a manually-controlled stripper. Central relay panels incorporating the temperature charts were used to control kilning."
Journal of the Institute of Brewing, Volume 66, 1960, page 499.

Interesting that they stuck with floor malting for the darker malts. Speaking of which the article includes a nice table of the different malts:

TABLE III
West German Malts
Pilsner  Martzen or Vienna  Munich
Steep temperature About 60" F. 60-66° F. 50° F. (3-4 days)
Germination 8-day, rising to 63° F. 8-day, rising to 68° F. 8-day, rising to 76° F.; stewing on last day
Kilning 20-hr. Maximum draught early. Temp. to 160º F. 20-30 hr. Maximum draught early. Temp, to 190-220° F. Less draught early. Finished at 230-240° F.
Analysis
Colour (E.B.C.) approx. 3° approx. 6° 9-12°
Fine/coarse difference (lb. per Qr.) 4 2 - 3 -

How does that compare to British malts? I thought you might ask that. SO I prepared another table:

British and Continental malts

Pale Ale Mild Ale Pilsner   Vienna  Munich
kilning 203-221º F 158º F 194º F 212-221º F
Colour (E.B.C.) 4-6º 6-9º 5.5-6º 15-25°
Source:
"Brewing Science and Practice" by Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes and Roger Stevens, 2000, pages 27 - 28.


The Pilsner, Vienna and Munich malts are of continental manufacture. Pale ale malt fits in somewhere between Vienna and Munich malt. The big difference in colour in the Munich malts tends to make me believe that they are different types. The one from the Journal of the Institute of Brewing being pale Munich, the other dark Munich.

Next time we'll be looking at brewing.

Tuesday, 16 September 2014

Westphalian and Hessian Lagerbier 1879 - 1893

Had my obsessive side passed you by, the current flood of Lager might have surprised. A regular reader would expect the unrelenting tsunami of tables. If such a beast as a regular reader exists.

Let's begin with doubt. I'm not sure what these analyses teach us. Just as well that's not my main reason for publishing them. It's mostly to do with identifying the regional groupings.

In the source, there's a heading to identify beers of a certain region. I don't have that luxury. Each beer is a row in a spreadsheet that I sort into all sorts of different orders. You can forget headers. The rows get shuffled all over the place.

Sorry to bother you with this. Me finding handy places to park stuff I don't want to lose.

When you have as much crap as I do - writings, research material, photos - you have to keep in some sort of order. To be able to find it back. That's why my self-published books exist. So I can keep track of what I've written.

Now I've got that out of the way, on with the beers. First those from Westphalia. As you can see, they're mostly from Dortmund.

Westphalian Lagerbiers 1879 - 1893
Year Brewer Beer Style Acidity OG FG OG Plato ABV App. Atten-uation
1879 Unknown Dortmund Dortmunder Lagerbier 1049.1 1015.1 12.21 4.40 69.25%
1884 Unknown Marienborn bei Sigen Lagerbier 2 bis 3 Monat alt Lagerbier 0.184 1051.0 1011.3 12.66 5.16 77.84%
1884 Barmer Aktien-Brauerei Barmen-Rittershausen Lagerbier Lagerbier 0.161 1053.0 1019 13.13 4.40 64.15%
1887 Westfalia-Brauerei Münster Lagerbier Dunkel Dunkles 0.317 1053.0 1015 13.13 4.94 71.70%
1893 Löwenbräu Dortmund Lagerbier Lagerbier 0.27 1055.0 1012.0 13.60 5.60 78.18%
1884 Gebr. Meininghaus Dortmund Lagerbier Lagerbier 0.02 1056.0 1013.8 13.84 5.49 75.36%
1887 Westfalia-Brauerei Münster Lagerbier Hell Helles 0.302 1056.8 1013 14.03 5.70 77.11%
1884 Victoria-Brauerei Dortmund nach bömisches Art Lagerbier 0.118 1059.0 1017.5 14.54 5.39 70.34%
1884 Victoria-Brauerei Dortmund goldfarbig Lagerbier Helles 0.152 1062.3 1019 15.31 5.62 69.50%
Average 0.191 1055.0 1015.1 13.61 5.19 72.60%
Source:
Chemie der menschlichen Nahrungs- und Genussmittel by Joseph König, 1903, pages 1102 - 1156

My guess would be that most were pale in colour. The one described as "nach böhmisches Art" almost certainly is.

In terms of gravity, they mostly look right for Export, though the source describes them as Lagerbier. I'd expect 13º to 14º Plato, which is what most of them are, with the average 13.6º Plato. At 72%, the attenuation is better than for most of the Lagerbiers we've looked at. Odd, because you'd expect attenuation to be worse in the stronger Export. The high gravity and relatively high level of attenuation mean that the average ABV is the highest so far, 5.19%

At almost 0.2%, the level of lactic acid is again rather high. Two samples have acidity over 0.3%. That's the sort of level you'd expect in a Stock Ale or aged Stout. I'm still trying to get my head around levels like that being in Lager.

Now the Hessian Lagerbiers. They're sort of from Hessen. Or they were back in the 1890's. But today Schmalkalden is in Thuringia. I must confess that I didn't notice. Dolores pointed it out to me when I asked if she knew where it was. She does, because she grew up not that far away. It's weird that so many samples are from Schmalkalden. It's not a huge town - the population now is only 20,000. Yet from the much larger Kassel, there's only one.

Hessian Lagerbiers in 1893
Year Brewer town Style Acidity OG FG OG Plato ABV App. Atten-uation
1893 Bühner Schmalkalden Lagerbier 0.211 1044.5 1012 11.11 4.21 73.03%
1893 H. Wiegand Schmalkalden Lagerbier 0.137 1045.1 1013.2 11.26 4.14 70.73%
1893 Messerschmidt Schmalkalden Lagerbier 0.262 1045.4 1012.5 11.33 4.26 72.47%
1893 Kaufmann Schmalkalden Lagerbier 0.271 1045.5 1012.0 11.35 4.35 73.63%
1893 C. Wolff Schmalkalden Lagerbier 0.137 1045.9 1014 11.45 4.14 69.50%
1893 Falk Schmalkalden Lagerbier 0.218 1046.0 1013.3 11.47 4.24 71.09%
1893 Cramer Schmalkalden Lagerbier 0.232 1046.3 1013.7 11.54 4.23 70.41%
1893 Wwe. Köhler Schmalkalden Lagerbier 0.152 1047.1 1014 11.74 4.29 70.28%
1893 Ritter Sauer Hersfeld Lagerbier 1048.1 1011.3 11.97 4.79 76.51%
1893 G. Wolff Schmalkalden Lagerbier 0.270 1048.3 1011.0 12.02 4.85 77.23%
1893 Hessische Aktien-Brauerei Cassel Lagerbier 0.185 1048.3 1012 12.02 4.71 75.16%
1893 Rückert-Siemen Schmalkalden Lagerbier 0.179 1050.0 1018 12.42 4.14 64.00%
1893 Lederer Marburg Lagerbier 0.14 1051.4 1015.5 12.76 4.65 69.84%
1893 Wwe. Lesser Schmalkalden Lagerbier 0.232 1051.5 1014.2 12.78 4.84 72.43%
1893 A. Wiegand Schmalkalden Lagerbier 0.148 1051.7 1009.8 12.83 5.46 81.04%
1893 W. Engelhardt Hersfeld Lagerbier 0.179 1052.6 1015.7 13.04 4.79 70.15%
1893 Missomelius Marburg Lagerbier 0.21 1057.0 1013.2 14.07 5.70 76.84%
1893 Kühn Schmalkalden Lagerbier 0.137 1060.3 1017 14.84 5.63 71.81%
1893 Missomelius Marburg Lagerbier 0.097 1060.6 1015.0 14.91 5.94 75.25%
Average 0.189 1049.8 1013.5 12.36 4.70 72.70%
Source:
Chemie der menschlichen Nahrungs- und Genussmittel by Joseph König, 1903, pages 1102 - 1156


The Hessian Lagerbiers have a much lower average gravity than the Westphalian ones - more than 5 points lower. Though they share a similar degree of attenuation, about 72%. Though the average seems about right for Lagerbier, some at the bottom end are a bit weak and the top two far too strong. Again, the average acidity is on the high side.

The table fun just doesn't end today. I've put together a table to compare the average values for Lagerbiers from different areas.

Bohemian, German and Austrian Lagerbiers
Beer OG FG OG Plato ABV App. Atten-uation lactic acid %
Bohemian Dark Lagers 1890 - 1895 1044.4 1014.2 11.09 3.91 68.13% 0.172
Bohemian Lagerbier 1876 1046.2 1013.3 11.51 4.26 71.25% 0.130
Bohemian Pilsener 1880-1890 1049.0 1013.6 12.18 4.59 72.09% 0.212
Bohemian Pale Lagerbier 1880-1890 1049.2 1014.9 12.22 4.44 70.06% 0.140
Hessian Lagerbiers in 1893 1049.8 1013.5 12.36 4.70 72.70% 0.189
Dresden Lagerbiers 1878 - 1880 1052.0 1013.4 12.90 5.01 74.37%
Lower Austrian Lagerbier 1876 1053.3 1017.0 13.20 4.70 68.17% 0.140
Hannover region Lagerbier 1878 - 1891 1053.4 1015.6 13.22 4.90 70.81% 0.134
Nürnberg Winterbier 1887 1053.6 1016.4 13.28 4.82 69.30% 0.232
Westphalian Lagerbiers 1879 - 1893 1055.0 1015.1 13.61 5.19 72.60% 0.191


You can see that the Hessian ones slot in just above the Bohemian ones. They're quite a bit weaker than any of the other German ones. While Westphalian Lagerbiers are, on average, the strongest. Not sure what the table tells us, other than that gravities were low in Bohemia.

Not sure what's next. Erfurt, maybe.

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
Burton
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
Source:
"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.

Thursday, 13 September 2007

Dortmund

Sic transit and all that. Forty years ago Dortmund was Germany's top brewing city. It brewed more beer than anywhere else, had the largest single brewery and was home to the most popular beer style. How did it all go so wrong?

Tell me if this sounds familiar. Ill-advised takeovers, panic mergers, jumping on the pils bandwagon and long-term decline in the region's heavy industry all played their part in dethroning Dortmund.

Dortmunder Union, Germany's largest brewery in 1965, was one of the forces behind Brau and Brunnen, a kack-handed - and ultimately disastrous - attempt to create a national brewery. Their beers have disappeared and the brewery has been renamed Brinkhoff's.

The Dortmund beer style - Export - has done a good imitation of mild, going from dominance to obscurity in a generation. It's now easier to find a Dortmunder in Holland

The Dortmund Brewing Industry
When Michael Jackson wrote his "World Guide to Beer" in 1977 Dortmund's breweries were still an impressive sight. "It is barely possible to leave the railway station without encountering a cluster of Dortmund breweries: Dortmunder Actien and Dortmunder Union in Rheinische Street, the Thier, Hansa, Ritter and Wenker Kronen breweries." he wrote. His walk would be very different today.

At the beginning of the 19th century Dortmund was an insignificant town of around 5,000 inhabitants. The breweries it possessed were pub-based brewhouses producing small quantities of top-fermenting beer. But all that was soon to change. As Germany began to industrialise Dortmund became a major centre for the coal and steel industries. The population boomed and with it breweries to slake the workers' thirst.

In 1842 Kronen was the first Dortmund brewery to swap to bottom fermentation. The lager they brewed was, as was usual at that time in Germany, a dark beer in the Münchner style. Throughout the the following 50 years a series of new, industrial lager breweries were established in the city. Organised on a similar basis to the city's other industries, they operated on a far larger scale than had ever been seen in North Germany. The small, alt-producing brewhouses were swept away.

Dortmund's industrial brewers continued to expand in the 20th century (though with some interruption from two world wars), peaking in the 1960's. In 1965 the city's DUB and DAB breweries were the largest in Germany.

As the popularity of Pils soared at the expense of Export, growth slowed, stagnated or even went into reverse. When, in the 1990's, the German economy plummetted into recession, the heavy industry of the Rhine/Ruhr was particularly badly hit. As output fell, Dortmund's breweries looked to mergers for salvation.

Seven breweries became two. But that wasn't the end of matters, oh no. The new millenium was no kinder to German brewing than the previous decade. As beer consumption falls and over-capacity is rife, even more drastic consolidation is taking place. The purchase of Brau & Brunnen (DUB) and Radeberger-Gruppe (DAB) by Oetker has left both Dortmund's remaining brewers with the same owner. Which one do you think they'll leave open? The answer is DAB - it has a greater capacity and a larger site.

The History of Dortmunder Beer
The classic Dortmund beer style Dortmunder Export has its origins in the 1880's. Before 1842, when Kronen brewed their first dark lager, the local style had been a variety of Alt.

Dortmunder Adambier was a strong, sourish top-fermenting beer. Wahl & Henius ("American Handy Book of the Brewing, Malting and Auxiliary Trades", 1902) has an analysis of the beer performed in 1889. It was around 18º Balling, 7.38% alc. by weight (9.4% ABV) and a lactic acid content about half that of a contemporary lambiek. In contrast to sour beers such as Gose and Berliner Weisse, Adambier, also called Dortmunder Altbier, was heavily hopped. It acquired its sourness much like Porter - through a long secondary fermentation. Bacteria in the lagering vessels slowly changed the beer's character. It needed to be stored for at least a year for this process to take place. At the end of the primary fermentation the beer it was not sour at all. Another beer of this type was Münsterländer Altbier - stilll brewed by Pinkus Müller in Münster today. (Source: "Jahrbuch der Versuchs- und Lehranstalt für Brauerei in Berlin, 1911", p.522)

Export
The new bottom-fermenting beer quickly gained popularity and was the main product of the industrial breweries founded in the second half of the 19th century.

The first pale lager was brewed by Dortmunder Union (DUB) in 1887. Initially, the beer was brewed at two strengths Lagerbier and Export. The greater popularity of the latter led to the dropping of the weaker beer and Dortmunder Export was born.

It's great to see the classic "brewing mistake" story used to explain the origin of DUB's first pale lager in 1887. According to their website, the brewer "accidentally" used pils malt. Total load of bollocks, if you ask me. What was the malt doing in the brewery if they weren't going to use it to brew a pale beer? In the 19th century dark lagers were made from 100% dark malt. As pils malt was quite a bit more expensive, they must have deliberately bought it to brew a pale lager. Anyway, only a total idiot wouldn't be able to spot the difference between pils and münchner malt at a glance.

After WW II, Export dominated the German beer market, accounting for as much as two thirds of sales. But this dominance was not to last. The meteoric rise of Pils in the 1970's quickly eroded Export's market share:

1968 Export 57%, Pils 19%
1970 Export 50%, Pils 25%
1976 Export 32%, Pils 41%
1992 Export 10%, Pils 64%
2000 Export 9%, Pils 67%
2006 Export 12.5%, Pils 60%

Since 2000 Export has made a little bit of a comeback and his clawed its way back over 10%. Whether this will continue remains to be seen. There's usually no return for dominant beer styles once they lose favour.

Dortmunder Export is a malty, full-bodied beer, hopped a little less than a Pils and with some residual sweetness. A bit like a strong West Country bitter (say Arkell's BBB), but fizzier. In the 1950's, a gravity of 13º Plato would have been the minimum, with an an alcohol content of 5.5% upwards. Gravities have fallen, especially in the last 30 years as the style's popularity has plummeted, and most Exports now barely reach 12º and 5% ABV.