Once the harvest has been completed, the barley will be prepared by the malters, according to the brewer's specifications. The hops will be dried first, then packaged as such or after they have been turned into pellets or extracts - for it is in the latter two forms that hops can be best preserved in time. Although a cocktail of cooking, chemistry and biology, beer brewing also demands rigorous techniques.

In the succession of delicate operations, one finds two principal stages. First of all there is the malting, then the actual brewing. We also discover some of the ingredients which make each type of beer a special sort : water, malt, sugar and hops.

 5 operations are necessary for brewing beer :

• in the first place, a source of starch, generally a barley malt;
• the malt grains are then ground into flour to liberate the starch;
• this starch is then transformed into simple sugars;
• yeast is added to transform the sugars into alcohol;
• then, at wish, the liquid is left to rest and then finally filtered.

At the end of this chain of operations, beer is obtained : sweet or bitter; clear or dark; cloudy or clear or sparkling; higher or lower alcohol content. That is the basic recipe used by brewers the world over.

The cooled wort passes through cylindrical/conical fermentation tanks, where pitching yeast prepared from a pure culture is added It was in 1830 that yeasts were identified as causes of fermentation. Once he had isolated these microscopic organisms, the German chemist Mayer named them "saccharomyces," a learned expression for "sugar mushroom." After Pasteur, it was the Dane, Hansen, who isolated the pure yeasts of fermentation at low temperatures, and then the yeasts known as "high," of which we use a very specific strain in Orval. Once pitched, the wort ferments vigorously, is covered with froth, and finally with yeast. The main fermentation lasts 4 to 5 days. The yeasts are active at a temperature between 15 °C and 23°C (56° and 66°F) and come to the surface with the froth during fermentation.

At the end of the fermentation, the young beer, still cloudy, is pumped into the holding tanks, where it matures, fines up, and takes on carbonic gas. The holding period lasts two to three weeks at a temperature of 15°C. It is in these same tanks that the yeasts, which have been very carefully kept in the Brewery laboratory, are added. As they develop in the later stages, they confer on the Orval beer its distinctive, slightly acidulous and so special character. A secondary fermentation in the holding tank gives the beer its incomparable taste, all the more so as fresh hops are added to heighten the bouquet.

Hops, which are late-comers to the symphony of seasoning used to make beer, come from a plant with multiple uses. They were known for their medicinal use, but it was beer brewing that made them a plant cultivated on an industrial scale. The most reputed varieties are the Bavarian Hallertau, the Slovenian Styrian Golding and the Alsacian Strisselspalt. These hops are used to flavour Orval beer. Before bottling, the beer is centrifuged to remove dead yeasts and hop particles in suspension. During this operation, liquid sugar and fresh yeasts are added so as to initiate the refermentation process in the bottle.

The bottling-line iis highly mechanised and can attain a rate of 26.000 33-cl bottles of Orval beer per hour.

For about 3 to 5 weeks, Orval beer referments in the bottle in storage halls climatised at 15°C (56°F). This process is similar to that of the principal fermentation. The carbonic gas produced by the fermentation saturates the beer and thus contributes to forming a creamy head.

It is only two months after it has been brewed and checked several times for quality that the Orval beer leaves the brewery.
It will bring pleasure to those who drink it if they observe the following rules :
Beer, a refined drink for the same reasons as wine, must be stored away from light, at a temperature between 10° and 15°C (46° and 56°C). It should be served at this same temperature and in its special glass, and its sediment should be tasted separately.

The gustative sensations will gain in nuance depending on the age of the beer. Young beer is characterised by a bouquet of fresh hops, with a fruity note and pronounced bitterness, light on the palate and a less firm collar than a beer of six months. The latter will feature a bouquet consisting of a blend of fragrances of yeast and old-fashioned hop. The bitterness is more diffuse and the taste has moved to a slight touch of acidity accompanying yeast and caramel flavours. Served without its sediments, a beer of six months or more, has a particularly bright appearance. It will be less so, if it is served at a temperature below 7°C to 8°C (44° - 45°C).

The brewery indicates the bottling and best-by dates directly on the label. Every consumer can thus easily know the age of an Orval beer, and whether it should be consumed rapidly or less so, depending on whether one likes this beer young, or after a few months or years in the cellar.