The World’s Oldest Malt and Brew House
Although much of beer’s dawn is shrouded in obscurity, we do know that beer is as old as civilization itself. We also know that humans have used two fundamentally different ways of brewing: an ancient way of making beer from bread that was practiced at least until the birth of Christ, and a modern way of making beer from malted grain extract that has been the standard at least since the Dark Ages.
The challenge in beer-making, unlike in wine-making, is to break down the grain’s complex carbohydrates (starches) into simple ones (sugars) that the yeast can ferment. Fruit carbohydrates are already sugars and wine can thus be fermented without any intervening process. But in grain, starches are converted into sugars by enzymes that become active only in warm, moist environments—such as the ancient beer-maker’s bake oven or the modern brewer’s mash tun.
Though we know about these two beer-making ways, oddly, we have next to no idea how ancient brewing metamorphosed into modern brewing, except—just perhaps—for a few tantalizing clues, hidden in an unassuming, sleepy archaeological dig in Bavaria, at the northern-most bend of the river Danube. Ignored by the world, this obscure site probably bears witness to one of the most profound revolutions in the art of beer making. To put this argument into perspective, first some historical background.
Beer Making in Antiquity
As soon as our hunter and gatherer ancestors stepped out of the fog of pre-history and settled down to farm, they also started to brew. The Sumerians were the first to do so, some 8,000 to 10,000 years ago, in the flood plains between the rivers Tigris and Euphrates in what is present-day Iraq. We know from Sumerian drawings and cuneiform scripts that these ancient brews were made simply from half-baked, moist loaves of bread crumbled into crocks of water and fermented spontaneously by airborne yeast. The result was a murky alcoholic quaff full of crumbs and floating husks.
The illiterate Celtic/Germanic tribes of central Europe, too, made their beers this way when they started to brew, probably sometime between the second and seventh millennium BC. We know so because of the discovery, in 1935, of an amphora-shaped crock of black wheat beer found in a Celtic burial site from the eighth century BC near the Bavarian city of Kulmbach. When unearthed almost 3,000 years later, the crock still contained traces of bread. It now ranks as the oldest evidence of beer making in Europe.
Beer Making in Modernity
Nowadays we make beer very differently. Instead of fermenting grain solids immersed in water, we produce a clean extract from malted grain and then ferment that. In that process, we steep raw grain in water, let it partially germinate, and then dry it in a kiln. This activates enzymes that convert unfermentable grain starches into fermentable sugars. Chemically, a similar reaction occurred in the baked loaves of the ancients but with much less efficiency. For brewing, we mill the grain, infuse it with hot water, and draw a sugar-rich extract, which we flavor (usually with hops) during a boil and ferment when cool.
The first written records of this modern beer-making method have come to us from medieval monks of the sixth to the 11th centuries. One of the most complete such descriptions was penned by Ekkehard IV, a Benedictine Abbot of St. Gall (in what is now Switzerland), the biggest monastery and brewery of the Dark Ages. In his chronicles of 1060, Ekkehard described how his monks threshed the reaped grain; moistened it until it sprouted; dried it in a kiln; crushed it in huge, water-powered mortars; mashed and boiled it in direct-fired kettles; and finally ladled the wort with wooden buckets through pressed-straw filters into flat wooden fermentation tubs.
For lack of earlier accounts of modern malting and brewing, it is generally assumed—though not proved—that the monks also invented the process. This paradigm, however, merely begs the question: How, where, and when did the ancient method of making beer from bread—as evidenced in the Kulmbach amphora—evolve into our modern method of making beer from wort? This question is one of the great unsolved mysteries of brewing history.
The Missing Link
Strangely, a puzzling archaeological find excavated in 1978 along the banks of the Danube River in Bavaria may hold the key to solving this mystery. The dig is inconspicuously tucked away between two family homes on a little street named Kornweg, in Grossprüfening, which is a quiet residential suburb of the city of Regensburg. A 30-foot walkway leads from a simple enamel sign, which reads enigmatically, Wirtschaftsgebäude (“economic building”), to a rarely visited, locked, 26-by 43-foot pavilion that was erected in 1983. It has glass walls on three sides through which visitors can view a cluster of excavations. The significance of this “economic building” for the history of beer making has gone all but unnoticed to this very day.
Within an oblong set of stone foundations are arranged—clockwise—a deep well; a water-tight basin at ground level; a kiln with a fire pit and a flue; and a stone-ringed fire place, about 3 feet in diameter. The probable date of the site, according to Dr. Andreas Boos, chief archaeologist at the Regensburg Historical Museum and keeper of the pavilion’s key, is the last quarter of the second century AD, when Regensburg was called Castra Regina, the largest Roman military camp in what is now Bavaria.
The Romans arrived in Regensburg and environs around 80 AD as part of their geopolitical expansion into central Europe. Initially they set up just a small military outpost. Regensburg was at the endpoint of a natural depression through the Bavarian Forest—a natural invasion route of Germanic tribes from the northeast in Bohemia. Emperor Marcus Aurelius decided to turn Regensburg into a serious bulwark. He constructed Castra Regina, completed in 179 AD, as a walled-in encampment for his Third Italian Legion of some 5,500 to 6,400 heavily armed Roman elite troupes.
Settlements soon grew up outside the walls of Castra Regina, one of which, about 2.5 miles from the Castra, was the village that has since become Grossprüfening. In these settlements, indigenous tradesmen, merchants, artisans and veterans from all over the Roman realm and, most importantly, innkeepers and ladies of easy virtue, supplied the Roman military machine with all the necessities—and frivolities—of life.
The archaeologists digging in Regensburg’s past had unearthed wells, water basins, kilns (mostly for drying flax), and fireplaces before, but they had never found these structures grouped together within a single workshop. Says Boos, “The combination of elements at the Grossprüfening site is unique and there is no piece of evidence that would tell us conclusively what the building was used for. Scientifically, we simply cannot be certain. Instead, we must treat the nature and arrangement of the components as circumstantial evidence and then draw logical inferences from the site’s layout and from what we know in general about Roman and Celtic/Germanic life at Castra Regina at the time.”
In the absence of proof positive, archaeologists have proposed—and discarded—many theories about the workshop’s purpose. One interpretation suggests that the site was a winery. But why would anyone need a well, a kiln, and a fireplace for pressing grapes and fermenting juice? “Besides,” says Boos, “there is only conclusive proof of wine drinking, not of grape growing and wine making, around Regensburg in Roman times.” Other archaeologists have suggested that the basin was used to blanch fruit and that the kiln was used to dry it. But this theory, too, is hard to sustain, because the basin is sunk into the earth like a small swimming pool and has no fire source.
Finally, a theory emerged that gave meaning to all four components at the site and to their arrangement. The interpretive signs inside the pavilion now claim that the building was used as a malting plant and brewery. Elaborates Boos, “Archaeologists, of course, are rarely experts in beer making. Consequently, most of my colleagues still regard the malting and brewing theory as highly speculative. Without firm knowledge based on hard evidence, however, this interpretation seems to me to be by far the most logical and persuasive of all that have been proposed to date.”
A Tantalizing Hypothesis
To the trained eye of a brewer and maltster, the site does indeed contain all the components of a modern malt and brew house, combined into one operation. But Roman? We have some evidence that the Romans occasionally flirted with beer making, but not on the systematic scale suggested by the Regensburg site. If their writings are to be believed, most Romans disliked beer. Instead, they preferred to haul casks of wine from Italy across the Alps to their military outposts—a colossal logistical undertaking.
There was probably never enough wine in Regensburg for the 12,000 troops and civilians who lived there. The Romans may not have liked Celtic/Germanic beer, but there was no practical alternative to it. When faced with the choice of either abstaining from or improving upon the local quaff from grain, they probably opted for the latter.
It is very likely that the Kornweg site was built by Romans but staffed mostly by Germans, simply because the Romans possessed the needed architectural and engineering superiority, while the Germans, who learned stone construction from the Romans, possessed the needed knowledge of brewing from raw materials. The Romans were probably able to de-construct the traditional Celtic/Germanic bread beer process and enhance it. By this hypothesis, modern beer making is a happy marriage between Celtic/Germanic knowledge of grains and Roman technological savvy.
Perhaps the initial impetus for a change in beer-making techniques was aesthetic. The civilized Romans might have wanted to eliminate the soggy crumbs and floating husks from the finished product. They probably discovered, however, that raw grain dunked in water does not ferment well, because, as we now know, yeast cannot metabolize raw grain starches. By trial and error, they must have stumbled upon the fact that gentle heat changes the outcome completely (because, as we know today, it stimulates the development of enzymes). At the Regensburg site, the well and the steeping basin could easily have served that purpose, with heated stones supplying the needed warmth. The basin was made of three layers, as only the Romans could have built it: an outer support of fist-sized, crushed limestone; a middle sealant of lime and gravel mortar; and an inner lining of impermeable cement-like limestone plaster. The basin probably functioned much like a modern steeping vat and germination box, with a moveable wooden cover to regulate the temperature and moisture.
Because moist grain spoils quickly in storage, the Regensburg maltsters dried it in the kiln. The kiln walls have a narrow ledge that probably supported a floor made of organic material. An open fire pit and a praefurnium (a work area for stoking the fire) are in front of a covered flue that sent hot air into a hypocaustum (a heat chamber) under the kiln floor. By modern standards, this design is rather sophisticated. In the Middle Ages, the hot-air kiln was “forgotten” and medieval maltsters used direct-fired floor malting instead, which often roasted, or even burned, the grain and always gave it a slightly smoky flavor. The indirect-heat kiln was only “re-invented” in the early 19th century in England.
The Regensburg brewers probably re-moistened their malt in a metal kettle placed over a fire, possibly suspended from chains. They then drew an extract, the wort, from the mash. The same kettle was probably used for both mashing and wort boiling. The kettle was never found. Because of the value of metal in antiquity, it was probably reworked into other items after it had fallen into disuse.
There is no evidence of fermentation at the site. An interpretive sign states that fermentation took place in a “warehouse that has been excavated further west.” Boos confirms that three Roman cellars have been unearthed within a few hundred yards of the presumed brewery but these are not visible or accessible to visitors. The Regensburg brewers probably collected the wort in containers and fermented it in these cool underground places. Once fermented, this extract beer was probably superior to all the primitive bread beers of old. It certainly could be made in quantities greater than the amount of wine the Romans could import.
Rewriting the Beer History Timeline
The Regensburg workshop is simply too well planned to have been a pure accident or a unique arrangement. It contains, in rudimentary form, exactly the same infrastructure that you still find in any modern malting plant and brew house anywhere in the world. Fundamentally, not much has changed from the processes employed in that tiny site along the Danube to the installations used by today’s multi-billion-dollar international malting and brewing industries.
The brewing methods had probably become standard by the time the Roman Empire collapsed. By 260 AD, the mighty Rome could no longer defend its far-flung borders. Castra Regina’s end came in the fifth century AD, when it fell into German hands for good. In 476 AD, the Germanic general, Odoacer, deposed the last Roman emperor, Romulus Augustulus, and Roman power all but disappeared from history. Roman achievements, however, left the societies they had touched transformed—and modern beer making is probably one of the least well known of these achievements.
If the above interpretation of the Regensburg site is correct—and we have good reason to think that it is—we can state that modern beer making with malting, mashing, and lautering existed in Bavaria, and probably in most of Germany, at least half a millennium earlier than anybody has hitherto imagined—and long before the Germans became Christianized and built their first monasteries in the fifth and sixth centuries. It means that medieval monks probably did not invent modern brewing methods but rather adopted and perpetuated them.
An interpretive panel at the Regensburg site seems to confirm this view: “This unusual Roman economic structure contains all the installations required for making a simple beer—just as in medieval monastery breweries.” The monks, however, deserve much credit for having preserved these techniques through the five centuries of intellectual and technological stagnation that we now call the Dark Ages. Without them, the achievements that Regensburg represents might have been lost.
This brings us to a momentous conclusion: Modern malting and brewing have always been considered a German invention, but they just might have been a Roman one, too. Within this context, the significance of the inconspicuous archaeological find at Kornweg in Regensburg could hardly be overstated.
Horst Dornbusch is the owner of Cerevisia Communications, a Massachusetts-based PR agency for the international beverage industry; a beer history enthusiast; and the author of numerous books and articles on beer-related topics.