bières refermentées en bouteille et bières en fût

What is Duvel Green, the beer released on draft?
First, a bit on Duvel in the bottle. Created by Albert Moortgat, bottled Duvel has become one of Belgium's favorite ales. The secret of its success lies in using only best-quality ingredients, and in the well-balanced, very specific, complex brewing and refermentation process that takes over 90 days.
After brewing and first fermentation - which takes about 30 days - the beer is tasted by the brew master and his staff. At this stage this beer is called "single-fermented." Typical Duvel flavors and aromas are already emerging, but the beer is lower in alcohol and carbonation, and the taste is slightly lighter and crisper.
When approved by the taste panel, the beer is prepared for secondary fermentation in the bottle, which involves adding additional yeast and sugar and bottling the beer. During 60 days the beer ferments and matures in the brewery warm-cellar and cold-cellar, developing the familiar flavors, aromas and alcohol that shape it into Duvel you know.

Now, a bit on Duvel Green: We in the brewery have enjoyed for decades the fresh, light taste of the 'single-fermented' Duvel, and we have traditionally cold-filtered and bottled a small portion of this beer for sale, but only at the brewery and a few selected locations in Belgium. The beer was labeled with a green label, as the nickname 'kleine' Duvel (or 'Green' Duvel) was used to describe the beer taken at a young stage of the brewing process of Duvel.
A small quantity of Duvel Green has now been made available on draft allowing a wider range of beer lovers to discover the beer.

Is this Duvel Green on draft the same beer as the classic bottle conditioned Duvel?
Yes and No. Duvel and Duvel Green are both brewed in the same installations, using the same ingredients (water, two-row summer malts, Saaz and Styrian Golding Hops) but as explained Duvel undergoes a second fermentation in the bottle while Duvel Green is cold filtered and packaged in kegs.

Duvel Green is certainly not a new beer, yet clear differences do exist between classic Duvel and Duvel Green in bottle or in keg.

The 'classic Duvel' is a sophisticated, full-flavored and aromatic Belgian Golden Ale, with clean, refined, silky sweet dry taste, while a 'Duvel Green' on draft has a gentle hoppiness, soft carbonation, and a subtle, smooth dryness with hints of fruitiness. The beer is not refermented, but is does have young Duvel flavors emerging from the first fermentation.
Two separate beers, yet from the same family. Familiar taste characteristics, but clearly different.

Why is there a difference between ABV levels on draft vs. in the bottle?

The single-fermented Duvel either leaves for a secondary fermentation (bottle-conditioning) in the bottle for the classic Duvel, or is conditioned for Duvel Green. The bottle-conditioned Duvel finishes at 8.5% ABV.

Preparing Duvel Green includes cold-filtering, balancing the raw materials for optimal flavor on draft, and some cold ageing of the kegs. This results in a specific ABV level of 6.8%.

A lot of questions on the forum are whether specific Duvel characteristics will be maintained? (Carbonation, foam head, aromas and flavors ...)

Comparing the Duvel Green on draft and the Duvel classic can be an interesting exercise. The clear differences and the similarities are what make the comparison stimulating.

It is clear that a lot of typical characteristics of Duvel in the bottle are created during the final fermentation of the beer in the warm cellar.

So yes, there is a difference between the two beers, which is why all bars carrying the Duvel Green on draft will also carry the bottle-conditioned Duvel.

When properly served Duvel Green will also have a large foam head. But it won't be as spectacular as the bottle-conditioned Duvel since the carbonation in the bottle is higher than in the keg. Also, the smaller 25cl draft glass does not have the carbonation-releasing small "D" carved into the bottom, as in the 33cl glass.
I hope this is an answer to many of the questions raised on the forum.

I'm happy to answer any questions you might still have, or you can ask them directly to our brew master, Hedwig Neven, who comes over to Boston for the Belgian Beer Fest.

Guernoulle :
Ben voilà, la question c'est :
Une bière a "triple fermentation" suppose une dernière fermentation en bouteille.
Une telle fermentation est elle possible en fût pression ?
Autrement dit : avons nous dans ce cas la même bière en bouteille et à la pression ?

En tout cas j suis impatient de pouvoir goûter de la Duvel au fût....