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Oud Bruin

At one time “sour brown ale” probably described most of what was being served in the local tavern. Beers were brown because the malting of barley was as yet an inexact science, temperature controls were shaky at best, and really “pale” malts were undreamed of. No sparkly, clear pilsners here.

Beers were sour because fermentation science was not only inexact, it was essentially nonexistent. It’s hard to use single-cell yeast cultures when you’ve never seen a cell (no microscopes) and the very notion of “yeast” as the source of fermentation is foggy and vague. There are a lot of nice micro-organisms more than happy to take up residence in a good wort of beer (or even a bad one), and if you don’t even know they exist, well, it’s tough to keep them out. No refrigeration (except in winter), no concept of microbiology, and no particular basis for sanitation. It’s true that hops, to some extent, provide a natural bacterial inhibitor, but what if you aren’t using hops?

Beers were ale because, well, because that’s what they were. Most brewers relied on the (unseen and unknown) properties of top-fermenting yeasts. Yeasts and other goodies.

So “sour brown ales” were pretty much the same as “beer.” The notion lacks a certain appeal to most modern drinkers. Hard to imagine putting that in an advertisement: “Pucker up with Augie’s Best Sour Brown Ale!” Over the years malting science has become worthy of the name, and barley malt comes out of the kiln looking more like Rice Krispies than Cocoa Pebbles.

Most breweries do their utmost to assure that nothing “bad” ever wanders into the fermenter. Yeast strains are monitored closely to assure their purity, not allowed to mutate or to consort with wild brethern or, shudder, bacteria. Roughly 75 percent of a brewery’s day can be taken up with sanitation.

But somewhere in the world the notion of “sour brown ale” has retained a certain panache. One little country — uh oh, you can see where this one’s going, can’t you? It’s a safe bet that if an ancient, funky-sounding beer has survived anywhere, it’s in Belgium that we find them: “oud bruins,” which means “old browns” in the regional language of Flemish.

Oud bruins are very much a product of Flanders in Northwest Belgium. Although sour brown ale sounds unpleasant, oud bruins are actually wonderful beers in which a mild to moderate acidity is balanced by a lush sweetness and fruitiness. For the most part they really are brown, but a sub-group is distinctively red.

Relatively few breweries produce oud bruins; these beers offer a special challenge to the brewer and require difficult techniques and, in some cases, specialized equipment to brew.

Certainly the most difficult aspect of brewing oud bruins is controlling the level of sourness. Typically, it is achieved through blending, much as control is achieved in winemaking. One batch of beer is brewed, perhaps to an original gravity in the mid-50s. The beer is allowed to age for many months, perhaps in wood, where it may acquire a winey taste or an acidity from lactic or acetic acid bacteria. Then the beer is blended with a fresher batch of a similar beer brewed to a slightly lower original gravity (about 1.045). The resulting blend is usually bottled and naturally carbonated. It may get a few more months in the bottle before release.

Perhaps the classic example of the brown oud bruin is Liefmans Goudenband (golden band), a beer so special that the bottle is hand wrapped in tissue (and can even be bought in 1.5-liter magnums — yum!). When new, the beer is very lush and round, but over time the sourness seems to become more pronounced. The beer is also used as the base for some of the most extraordinary fruit beers on the planet: an intense kriek (black forest cake in a glass!) and a frambozen (raspberry). Both are good dessert beers.

Another oud bruin I’ve found in the United States is Roman Dobbelen Bruinen, which seemed somewhat less sour than the Liefmans. It was also considerably cheaper, for some reason, and thus a bottle ended up flavoring a dish of beef carbonade, a classic (delicious) Flemish entree.

We tread now on shaky ground, for Michael Jackson deems the “red” beers of Flanders (primarily brewed by Rodenbach) as a distinct style. Others, however, consider them simply a variation on oud bruins, and I’ve read at least one report of a Rodenbach brewer who made the same assertion. Rodenbach’s beers are certainly red rather than brown but otherwise are very much in the same tradition.

Rodenbach beer is brewed from a proprietary blend of pale and Vienna malts and, curiously, corn grits. It is then fermented with the house yeast blend, containing as many as 20 strains, and conditioned for about five to six weeks. This is the “young” beer. It accounts for about 75 percent of the volume for blending in the standard Rodenbach Bier. The “old” beer goes through the normal fermentation and then is further aged for 18 to 24 months in tremendous oak casks, which are home to a mixed culture of Lactobacilli and other bacteria, gaining in color and acidity. Most of the aged beer is blended with the young beer to make the standard beverage, but some is bottled “straight” as Rodenbach Grand Cru, the brewery’s equivalent of a single-barrel bourbon. Both beers are sweetened with caramelized sugar at bottling and then flash pasteurized. A third beer, Alexander Rodenbach (named after the founder) has cherry essence added, again to balance the tartness of the base beers.

If oud bruins present a challenge to the commercial brewer, they offer nightmares to the homebrewer. The materials and techniques used in Flemish breweries have been developed and handed down over centuries and may not work for homebrewers. Certainly, few of us have access to oak casks rich in the proper microflora, nor do many of us have the patience to wait two years for a beer to emerge that can then be blended with yet another beer. Control of errant micro-organisms is particularly difficult at home, and once started, Lactobacilli are difficult to stop. The homebrewers on the cutting edge of experimentation (members of the Lambic Digest group, for example), consider oud bruin to be one of the toughest Belgian styles to reproduce.

There are some alternatives for adding sourness that are worth trying. A “sour mash” technique calls for letting the mash (or a portion of the mash) sit overnight at warm temperatures, thus encouraging the growth of souring bacteria. After the initial acidification, mashing is carried on as usual and the sourness created by the bacteria passes on to the finished beer. Although this is not, apparently, a technique used by Belgian oud bruin breweries, it does have the potential to add the necessary acidity.

Another method is to add food-grade lactic acid (available from pharmacies and some homebrew suppliers) to the finished beer. The truly experimental brewer, of course, will pitch Lactobacillus cultures into the nearly finished beer after fermenting with one of the mixed-culture Belgian strains available today.

Oud bruin grists ought to be built from Belgian malts, primarily pilsner malt, with some aromatic malt, cara-Munich or cara-Vienne, and perhaps a dash of Special B caramel malt. Wheat malt or flaked wheat would also be appropriate. Dark roasted malts, with their characteristic bitterness and burnt flavors, are not welcome. Much of the color in the darker oud bruins apparently derives from caramelization of the wort in very long boils (which would also intensify the richness of the flavor), so roasted malts are completely unnecessary.

This is not a beer in which the use of malt extract for the base should be any sort of handicap, provided that good specialty malts are added. Many extracts have a sort of caramelized flavor that can interfere with certain beer styles, but for oud bruins the flavor may even be an asset.

There are hops in oud bruins, but you would never know it to taste them. Hopping rates should be very low, as bitterness and sourness make poor companions. Any good British or Continental hops, particularly varieties with low alpha-acid content, should work, and they should only be used early in the boil, never where they would add flavor to the beer.

Brewing oud bruins at home is strictly experimental. Much of the available “research” is hypothetical, especially given the long lag times between brewing and verifying results. The other aspect of research is simpler: Go to your local well-stocked beer store and pick up bottles of Liefmans Goudenband, Kriek, and Frambozen, as well as Rodenbach’s three variations on the “red” theme. Drink them carefully and thoughtfully, and consider whether they aren’t worth a few centuries of work to produce.

Issue: May 1997