Bière De Mars is a French term that literally translates into “March Beer” in English. It refers to a type of low-alcohol lambic beer that was made in Belgium and was quite popular until the start of the 20th century, when production declined and eventually ceased. It is closely related to the faro style of beer but was much weaker in gravity and alcohol, and kept unsweetened. See faro.

Bière de Mars was traditionally made from the second and/or third runnings from the lauter tun during the production of lambic beer. The net result and goal of the brewer was to make a refreshing drink during the warmer months of the year. The flavor of Bière de Mars most likely was not as good as lambic, geueze, or other ales because the wort from second and third runnings would have been very high in tannins that would have given an almost mouth-puckering astringency to the beer. Interestingly, while many European brewers made stronger beers to be released in the month of March, such as bock, the brewers of Belgium tried to make faro and Bière de Mars as refreshing, low-alcohol alternatives. This somewhat contrary or rebellious way of brewing has been a trademark of Belgian brewers for the last couple of centuries. During the 1990s the Frank Boon Brewery in Belgium reintroduced a type of Bière de Mars that was labeled as Lembeek’s 2%. See boon brewery. It was a lightly spiced lambic style of beer with 2% ABV. Although refreshing, this brand failed to find a market and production ceased.

The traditional method of brewing Bière de Mars includes a lambic grist of 30%–40% raw wheat and 60%–70% malted barley. The hops used were typically Belgian and included varieties from the southern Belgian hop-growing region around the town of Poperinge, such as Northern Brewer and Brewer’s Gold. All hops used in lambic production were stored to reduce the oil and alpha-acid content and therefore to reduce the potential flavoring and bittering components. The intentionally aged hops were used mainly for their antimicrobial effect. Mashing was carried out to optimize the growth of microorganisms associated with spontaneous fermentation and favored high levels of free amino nitrogen and unfermentable sugars. To obtain this type of wort, the brewer would mash in the grist at a low temperature around 30°C (86°F), and use a stepped decoction to increase the mash temperature up to a high near 80°C (176°F). See decoction. Multiple holds at various temperatures were carried out, resulting in a very long day for the brewer.

The first runnings from the lauter tun were used for lambic production, while the second and third runnings from the lauter tun were isolated for faro and Bière de Mars production. In the brewkettle, whereas typical beers are boiled from 60 to 90 minutes, lambic styles could be boiled up to 5 hours, always using aged hops. After boiling, the wort was transferred to a coolship, a shallow, large open tank where the wort was cooled and allowed to be infected by airborne microorganisms that began the spontaneous fermentation. See coolship. Brewing traditionally took place only in the colder months of the year so that the wort would cool quickly—1 to 2 days—using only the ambient air temperature. Usually, the coolship was located on the roof of the lambic brewery and was well-protected from the elements, except for strategically positioned air holes and vents to allow the air to circulate from inside the brewery to the exterior and vice versa. After the wort had started fermenting, it was transferred to oak barrels where the Bière de Mars finished fermenting and could be aged for several months before being served in the warmer months.

In the United States and France several craft breweries have introduced Bière de Mars varieties that differ from the historic Bière de Mars found in Belgium. The French versions are usually called “Bière de Printemps” (“spring beer”) and are stronger versions of Bière de Garde, usually containing around 6% or 7% ABV. See bière de garde. They are also usually brewed with only the best malts and hops available so that the flavor has a fuller malt taste with pronounced hop character. The US versions of Bière de Mars are also brewed in the newer French tradition and have high alcohol contents (6%–7% ABV) with full malt and hop flavors. Craft brewers such as New Belgium, Jolly Pumpkin, and Southhampton Publick House all have offered modern versions of Bière de Mars.

See also belgium and lambic.