03/09/2011 03:58 pm ET | Updated Sep 20, 2011

Brussels Cantillon Brewery: Last Lovers Of Spontaneous Fermentation (PHOTOS)

When I think of museums, I general think in the past tense. In the case of the Brussels museum of Gueuze, things are still very much alive and kicking. *SEE PHOTOS BELOW*

The museum is better known as the Cantillon brewery, one of the last functioning brewers of a spontaneously fermented beer called Lambic.

I headed over to Cantillon on one of their twice-yearly open days when they brew a new batch of beer in one day. You are given a guided tour of the brewery and discover the beer process at different stages. The brewery has been making Lambic since the 1900's and it's still in the same family of master brewers. It's a fascinating process, even for non-beer lovers and you can feel the passion of the people working there seeping out their beer soaked pores.

If this spontaneous fermentation sounds a little bit magical, well it is, as they explained on the tour it's 'natural' magic. Natural in the sense that they mix all the ingredients together, step back and let nature do its business.

As you may gather, I'm not an expert in the beer making process but what I understand is that 'conventional' beer is cultivated using exact strains of brewers yeast. At Cantillon they let the natural wild yeasts and bacteria that reside in the air and in the timber do the cultivation.

So you mix raw wheat, malt barley and dried old hops, brew it, collect the wort (the liquid that comes from mashing the grains) by filtering, cool it down in open air, let the natural infection by bacteria and yeast happen and then pump all this into old wine barrels and let the spontaneous fermentation begin. This produces the raw Lambic. They use this to make a final product called Gueuze that is a blend of Lambic from three different years. They only brew during the cold seasons as the heat during the summer months means unfavorable micro organisms.

The master brewer has a big part to play at Cantillon, with its natural process, it becomes impossible to make a standard beer. The brewer must taste the new barrels and play with the mix of ages until he comes upon a blend that he deems up to the Cantillon quality level.

The result is a very unusual, dry, tart beer and a must-try for any keen beer connoisseur. The bottles are closed with a cork and, very unusually for beer, can be kept for a long time and can have a far deeper taste after a few years in the wine cellar.

They also use the Lambic to make a fruit beer called Kriek by mixing cherries and with a young Lambic beer.

Cantillon are open for tours all year round but if you are in Brussels during the first Saturday of March or October, definitely visit the open days.

Cantillon Brewery