Dubbel

At Westmalle the Extra (4.8%), the Dubbel (7%) and the Tripel (9.5%) get the same treatment: top fermentation with refermentation in the bottle. That is one main fermentation in the tank and one refermentation in the bottle. The number of fermentations therefore does not explain the name.

'Twice as strong' is not right either. The BJCP gives 6–7.6% alcohol for a dubbel, and 4.8–6% for the lighter monastic table beer (Belgian Single).

Westmalle itself gives a different explanation. In the 1920s 'Dubbel Bruin' appeared at the abbey. According to the brewery that was a richer variant of the brown beer that the monks had been brewing for decades, 'with twice as much malt'. That is where the name is said to come from. On the product page of the Dubbel, Westmalle speaks of a doubling of the ingredients of the light beer that the monks brewed for themselves. These are the brewery's stories about its own beer, and they differ per page. We have not seen an independent archive document for them, and it says nothing about how other brewers make their dubbel.

In practice a tripel is heavier than a dubbel, but the names do not stand for a fixed multiplication.

The colour of beer comes mainly from the grain. The more caramelised, roasted or darkly kilned malt the brewer uses, the darker the beer. CraftBeer.com of the Brewers Association expressly adds that colour does not equal alcohol content or mouthfeel. A quality guide of the Brewers Association for the trade also writes that colour sometimes suggests strength, but often wrongly.

The style guidelines show it in black and white. An Irish stout is black from dark roasted malt or barley, but according to the BJCP has 3.8–5.0% alcohol. A Belgian tripel is deep yellow to light amber and has 7.5–9.5%. The Brewers Association gives the same picture: a dry Irish stout has 4.1–5.3% at a colour of 80+ EBC (black), a tripel 7.1–10.1% at 8–18 EBC (pale). Such a stout does not have to be heavy either: the BJCP calls it remarkably smooth, with a medium-light to medium-full body.

Of course there are also dark beers that are strong, such as imperial stout (8–12% according to the BJCP). That is due to the amount of sugar that was fermented, not to the colour.

Trappist is a label of origin. It says where and under whose supervision a beer is made, not how strong it is. You can see that from what the Trappists themselves brew.

According to the International Trappist Association, La Trappe brews under the Trappist label, among others, Epos and Nillis (both 0%) and Puur (4.5%). Besides Dubbel and Tripel, Westmalle makes the Extra of 4.8%, which came out of the light beer that the monks had brewed for their own use since 1836. Chimay Gold (4.8%), Tynt Meadow blond (5%) and Tre Fontane Tertia (5%) are other Trappists under 6%.

The image is not entirely out of thin air. On the monastic beer styles, such as dubbel, tripel and quad, the BJCP writes that many of them are strong. But the BJCP also describes the lighter table beer that monasteries brew as the daily portion for the monks: the Belgian Single, with 4.8–6% alcohol.

With bottle refermentation, some sugar or wort is added to the beer at bottling. The yeast then makes the carbon dioxide in the bottle. The BJCP calls bottle refermentation a common characteristic of the Belgian monastic beer styles, and under the HORAL rules Oude Geuze and Oude Kriek must referment in the bottle. That yeast then sinks to the bottom is normal. A guide from CraftBeer.com (Brewers Association) even recommends storing speciality beer upright, so that the yeast sinks to the bottom.

Whether you pour the layer along differs per style. With weizen the brewer may, according to the BJCP, indicate whether the yeast should be swirled up. Australian Sparkling Ale is, according to the BJCP, usually poured with the yeast. Witbier is, according to the Brewers Association, traditionally poured cloudy. With tripel the BA, on the contrary, writes that you are not supposed to swirl up the yeast on purpose.

One caveat. Contamination with wild yeasts or bacteria can, according to the Brewers Association, cause cloudiness and flakes, and in addition off-aromas and off-flavours, sourness or a bottle that foams over when opened ('gushing'). But in a beer that has been refermented in the bottle, a layer of yeast at the bottom is not in itself a sign of spoilage.