Discover the art of brewing
The Brewing Process
Brewing beer
From hop to beer
Every day, we brew up top-quality specialty beers to give you, the consumer, the best possible beer experience. For this, we use carefully chosen ingredients, while also investing in both state-of-the-art equipment and the best people to manage the brewing process.
The best ingredients
Water, malt, hops, yeast and tonnes
of passion for the art of brewing
1 
Malting The brewing process starts outside the brewery walls, in malt houses both at home and abroad. There, the grain is ‘malted’. Malting is the process of readying grains – in beer, we’re mostly talking barley – for brewing through cultivation, germination and kilning. Choosing the right malt is crucial when it comes to the beer’s final colour, aroma and flavour. In the brewery, the malt is ground or put through a malt mill. The malt is milled wet so that it can be dissolved in water during the next step of the brewing process, while the chaff serves as a filtering agent.
2 
Mashing During mashing, we mix the water and milled malt to form a ‘mash’. At this stage of the process, the starch contained within the malt is converted into fermentable sugars. Here, the brewer is able to play with different temperatures. By heating the mash for shorter or longer periods, they are able to determine the composition of the resultant ‘wort’.
3 
Filtering After mashing, we are left with a high-sugar liquid containing solid chaff particles. For the next step of the brewing process, we separate these residues, or ‘draff’, from the ‘wort’, with the chaff serving as a filtration layer. The draff is collected and distributed to dairy farmers. Once the mash has been filtered, we are left with the wort, a high-sugar liquid that will soon be turned into beer.
4 
BOILING By boiling the wort, we are making it sterile, precipitating any cloudiness (hot break) and giving the hops their bitter flavour. In the brewing world, we only use hop cones from female hop plants, sourced the world over, using a balance of both bittering and aroma hops.
After boiling, the wort is left to cool. For our top fermented beers, we are talking down to 18-25°C. For our spontaneous fermentation beers, the still-boiling wort is pumped into an open cooling tank.
After boiling, the wort is left to cool. For our top fermented beers, we are talking down to 18-25°C. For our spontaneous fermentation beers, the still-boiling wort is pumped into an open cooling tank.
5 
FERMENTING During fermentation, the sugars in the wort are converted into alcohol and carbon dioxide. Only after fermentation can we start referring to the liquid as ‘beer’. We employ three types of fermentation:
For top-fermented specialty beers (e.g. Kasteel, Filou, Brigand), fermentation occurs at a higher temperature of 18-25°C.
In mixed-fermentation specialty beers (e.g. Bacchus), the liquid is pumped into upright oak barrels following primary fermentation. Here, lactic acid fermentation is allowed to take place.
In spontaneous fermentation specialty beers (e.g. St-Louis), the wort is transferred directly to an open cooling tank after boiling. Here, the wort comes into contact with surrounding microflora.
For top-fermented specialty beers (e.g. Kasteel, Filou, Brigand), fermentation occurs at a higher temperature of 18-25°C.
In mixed-fermentation specialty beers (e.g. Bacchus), the liquid is pumped into upright oak barrels following primary fermentation. Here, lactic acid fermentation is allowed to take place.
In spontaneous fermentation specialty beers (e.g. St-Louis), the wort is transferred directly to an open cooling tank after boiling. Here, the wort comes into contact with surrounding microflora.
6 
LAGERING Once primary fermentation is complete, the yeast is separated from the young beer, with the remaining liquid left to rest and mature in lagering tanks. During lagering (or ‘maturation’), specific aromas are formed, while less pleasant flavour components disappear. In other words, it is at this stage that the flavour of the beer is fine-tuned.
In the case of fruit beers, this is the stage in which we add the fruit. After six months, the pulp is completely dissolved, leaving the beer with a delicious fruity flavour. For Kasteel Xtra, the brewer applies the ‘dry-hopping’ technique. Here, extra hops are added during lagering, resulting in a subtle hoppy aroma.
In the case of fruit beers, this is the stage in which we add the fruit. After six months, the pulp is completely dissolved, leaving the beer with a delicious fruity flavour. For Kasteel Xtra, the brewer applies the ‘dry-hopping’ technique. Here, extra hops are added during lagering, resulting in a subtle hoppy aroma.
7 
filtering For the second time in the brewing process, filtering is again required. This is necessary to remove any leftover yeast or cloudiness. As with the draff, the residual yeast is kept in silos until being collected by an authorised distributor.
8 
bottling Once the lagering process is complete, the beer can finally be bottled. Bottling takes place in our high-tech bottling plant, run at full capacity on Tuesdays, Wednesdays and Thursdays. For our secondary-fermentation beers (e.g. Kasteel Tripel, Kasteel Xtra, Filou, Brigand), we add sugar and active yeast to the concoction before bottling. Once bottled, these beers are allowed to referment in a warm room at 23°C.
Since 2019, we have also been operating our in-house canning line – a first in the world of Belgian specialty beers. Finally, our automated barrel line also fills up to as many as 120 barrels per hour.
Since 2019, we have also been operating our in-house canning line – a first in the world of Belgian specialty beers. Finally, our automated barrel line also fills up to as many as 120 barrels per hour.
9 
Tasting Throughout the entire brewing process, we’ve gone through and carefully scrutinised every step to ensure the quality of our specialty beers. Now, time to taste! Does the beer have the desired level of bitterness? Are the fruit aromas coming through enough? These are questions we can only answer at the end of the process. Once approved, the beer is ready to be shipped off, allowing you, the consumer, to finally taste our craft.
Want to see the brewing process with your own eyes?
Book your brewery visit and discover every step of our brewing process.
