Production

Malt milling.

Barley malt is the basic raw material needed for the production of beer, whilst other cereal grains such as wheat, maize and rice are widely used in the brewing process. Malting of the barley is a procedure that can be briefly described as a process aimed to activate the enzymes responsible for the degradation of starch to simpler fermentable sugars which could be assimilated by the yeast during the fermentation of the beer and produce alcohol.
Initially, the malt must be milled and coarse -grained in order to become the starchy endosperm better accessible for the malt enzymes and improve the extraction process. The milling procedure is very important as on the one hand directly affects the extraction of the sugars and proteins and on the other, the separation of the husks from the endosperm of the grain is essential for the subsequent wort filtration.

Mashing-in

Mashing starts with mixing the grist (grained malt) and hot brewing water in the Premasher just before entering in the “mash tun”. The hydration enables the malt enzymes to become active.

Extraction – Mashing

Depending on the degree of malt modification and the type of beer that we are producing, the mashing temperature increases gradually in order to activate specific enzymes responsible for the degradation of carbohydrates and peptides in simpler forms of sugars and proteins that can be metabolized by the yeast during the alcoholic fermentation.
The temperature must increase uniformly in the whole mash as the optimal activity of the specific enzymes depends directly on the temperature. That’s why the Mash-Tun is equipped with a powerful mixer and insulation in order to achieve a homogeneous mash and avoid any heat loss to the environment.

Wort Separation (Lautering)

During the lautering process (also called “wort separation” or “mash filtration”) the undissolved substances are separated from the wort. The insoluble part (spent grains) is consisted of the husks, the seedling and other insoluble material. A spent grain filtration layer is formed on a welded wedge wire false bottom which is placed above the bottom of the lauter tun.
The first wort collected from the bottom of the lauter tun is very turbid because the fined grained particles of the malt have passed through the false bottom. The first cloudy wort is pumped back and filtered again through the spent grains until the withdrawn wort is clear. In order to recover all the extract, sparge water (75–78oC) is used to wash the mash and to displace the wort downwards. When the sugar content in the drained wort is low, the filtration operation is completed and the spent grains are discharged.

Boiling

Wort boiling is a complex process during which a wide range of chemical, physicochemical, physical and biochemical reactions occur: evaporation of water, isomerization of a-acid of hops, coagulation of unstable proteins (hot break formation), wort sterilization and inactivation of enzymes to fix the wort composition, removal of undesired volatile aroma compounds (DMS), acidification of the wort (PH reduction) etc.
Wort boiling is the most energy-intensive stage in the brewing process. During boiling the addition of hop takes place which contributes to the aroma and the bitter taste of beer.
The flavour of the final product depends on the variety of hop used and the time of addition of the hop into the boiling wort.

Centrifugation

After the completion of boiling, the sterilized wort is centrifuged in a tank with a specific geometric shape (whirlpool). The aim of centrifugation is the natural clarification and removal of the solid residues of the wort that were created during boiling and the hop addition.
The inlet of the wort in the whirlpool, is tangential in order to create an internal centrifugation. The centrifugal force leads the solids residues with larger weight in the center of Whirlpool which allows the removal of the clarified wort from an output valve that is placed at the perimeter of the tank.

Cooling

Additionally, the clarified wort which has a temperature of almost 100oC is cooled at 12-16oC and is racked in fermentation tanks.

Alcoholic Brewing

The cooled clarified wort is inoculated with a yeast strain in order to start the alcoholic fermentation. At this stage, the sugars that are extracted from the malt are metabolized from yeast to alcohol and carbon dioxide.
The alcoholic fermentation in the modern breweries takes place in specific cylindroconical tanks, called unitanks. These special tanks, due to their specific geometrical shape, allow the removal of the yeast from the bottom and give the opportunity to continue the maturation of the beer in the same tank (without any further racking).

Maturation

Once the alcoholic fermentation is completed and sugar is almost totally metabolized, the alcoholic fermentation rate slows down and the yeast is removed from the tank.
At this stage, the temperature of the beer decreases gradually and approaches 0oC, in order to accelerate the yeast’s precipitation drifting together cold sensible proteins which are coagulated.
Simultaneously some phenolic compounds with unpleasant aromas become insoluble making the beer taste smoother and fruitier.

Filtration

With the filtration we achieve the stabilization of taste and the limpidity of the beer. Mention that not all types of beer are filtrated, as some of them are bottled unfiltered or are bottled conditioned.
The filtration allows the removal of solids and yeasts from the beer. Depending on the filter’s porosity, it is possible to remove all the micro-organisms that can possibly contaminate and alter the beer’s taste (sterile filtration).

Packaging

Packaging is the procedure that allows us to transfer the beer from the tanks to bottles or kegs, in order to be distributed to the market.
During bottling or kegging it is extremely important to avoid any oxygen uptake as oxygen is the biggest enemy of the beer.
Simultaneously, bottling procedure has to be done under sterile conditions as the presence of micro-organisms can contaminate the beer and create undesired refermentation in the bottle and subsequently organoleptic deterioration of the product.