Resurrecting antique ale

A microbrewery in Finland’s Baltic Sea archipelago of Åland has recently launched a beer with a 19th century recipe. The formula is derived from the chemical analysis of contaminated booze recovered from a schooner that was shipwrecked some 170 years ago.

Discovered in 2010 just south of Åland, the ship has not been identified but archaeological evidence suggests that it sank in the 1840s. It was loaded mainly with luxury goods, but divers also found a few beer bottles. When they brought five to the surface, one cracked and the liquid foaming from it still tasted like beer.

Two of the bottles were subjected to chemical analysis by researchers at Finland’s government-owned VTT Technical Research Centre — the largest multidisciplinary research organisation in northern Europe. The analysis, reported in Journal of Agricultural & Food Chemistry, showed a high sodium ion content, suggesting that the beer had become diluted with seawater. The samples also had high levels of organic acids produced by bacteria, giving them vinegary, goaty and soured milk flavours that overpowered the original flavour. However, taking this contamination into account, the analysts were able to build a picture of the beer’s probable original components.

The hop content of the samples showed that the two bottles had contained different beers, one using more hops than the other. Neither displayed much of the typical bitterness or hoppy aroma of today’s beers, but this is not surprising because hops were less important in the 1800s than in modern beer production.

The beers also contained large numbers of dead micro-organisms, but the researchers were surprised to find four species of living lactic acid bacteria — typical of beers of the early 19th century. These bacteria have been used in fermenting the replica beer.

And the analysis found yeast-derived flavour compounds similar to those of modern beers, although some were in unusually high or low concentrations. In the 1840s beers were produced using wild yeast strains that became specific to local brewers. Fermentation was carried out in wooden vessels open to the air — and therefore subject to airborne contamination — and each new brew was pitched with the entire microbiota collected by skimming previous batches. It is therefore no surprise that the flavour compound profile may have differed from modern beers, which depend on pure yeast cultures unknown in the 19th century.

The replica beer, called Stallhagen Historic Beer 1843, is described as a golden yellow brew that lacks the typical bitterness and hoppy aroma of modern beers. Its taste profile is said to be almost wine-like, with a distinct fruitiness and a subtle spiciness. Its alcohol content is 4.5 per cent by volume. It is on sale only in southern Finland and eastern Sweden.

Through co-operation between the Stallhagen brewery and the AÌŠland government, profits from the beer’s sale will support marine archaeological research, maritime history and environmental measures in the Baltic Sea.