The brewing process includes the following operations:
to shoot the malt
to batter / mash
cooking (+ hopping)
removal of hops and hittedrab
cooling + kalthopfung + removal cold drab
The whole malt grain can not simply be used in the brewery. First the malt will have to be scraped, which is not comparable to grinding or crushing. Scraping is indeed a purely mechanical operation, but is very important for the natural conversion during the mashing process, for the filtration and for the qualitative composition of the wort, the fermentation and the beer quality. The intention of cutting is to reduce the flour in the malt grain and to keep the chaff of the grain as far as possible, so that the chaff layer can later serve as a filter. The scraping is done with a scrap mill that has six rollers. Shakers are standing in between the rollers. The distance between the rollers is different, as is the rotation speed of the different rollers.
In a classic brewing room (of course also at the Alfa Brewery) the scrap mill is located above the brewery hall, so that the malted malt falls through the pipe in the batter tub. Before proceeding to the brewing room, just a statement of the different brewing terms, which mostly come from German. The spring water used in fogging is called “herd”; the “headwort” is created during mashing; the washed out wort is called “Nachguss”; the main and Nachguss together is called “collected wort”, which after boiling is called “boiled wort”, (rash wort) and after cooling it is called “chilled wort”. The cooled wort is also called procrastination. The sugar (extract content) dissolved in the wort during brewing is called the root wort content. To make the puzzle even more complicated, the actual and apparent extract content is known. The actual extract content (in degrees Plato) consists of only sugar, the apparent extract (in degrees Balling) from all soluble substances. In the Netherlands, on a label, in order to avoid confusion, the root content may not be mentioned. The alcohol content is only indicated in percent by volume, because weight percentages confuse.
Make a fitting
The amount of malt used for the wort preparation of one brew is called the “deposit”. The ratio of batter water to the deposit depends on the extract content that the main wort must have. The higher the extract content, the more alcohol the final beer will contain.
For Alfa Superdortmunder, Bokbier and Lentebok an extra thick batter will have to be made to arrive at a high initial wort content.
The purpose of mashing is twofold: to dissolve water-soluble substances in a soluble manner by making insoluble substances soluble by enzymatic action (and therefore fermentable). The soluble substances include sugars, amino acids, minerals and some vitamins. The insoluble substances include the starch, fat and proteins. During the temperature rise, there are several breaks that greatly influence the taste and quality of the end product. Examples are protein rest (50 ° C), β-amylase (64 ° C) and α-amylase (74 ° C).
At the end of the mashing process, the mash consists of a mixture of undissolved substances (trot or bostel) and dissolved substances (wort). After mashing, these two substances must be separated. This is done by filtering or clarifying. The wort is further processed into beer. The bostel is ideally suited as animal feed. Many agricultural companies therefore want to use Alfa’s bostel. The clarification can be done by means of a filtration tank or clarifying tray. The clarification tray has a sieve bottom, which causes the wort to sink slowly. The wort is checked by means of the so-called drip tray for color and root content and for saccharification.
After the mash has been cleared, the wort is pumped into the brew kettle. The actual brewing takes place here. After all, the word “brewing” is etymologically related to the word “cooking”. The purpose of cooking is to evaporate the wort until the desired extract content or initial wort content has been reached. In addition, a so-called natural root stabilization occurs due to protein clumping, pH drop, color increase, taste development, enzyme destruction and sterilization. The hops can also be added during cooking.
The protein (and tanning) clotting, the pH drop and the enzyme destruction is important for fermentation. Sterilization and hop-delivery are important for the shelf life and taste of the beer.
Removal of hop residues
The wort will now have to be filtered. The warm cloudiness or heat-bath must be removed before cooling and fermentation, otherwise it will inhibit the fermentation and the color, taste and foam properties of the subsequent beer will deteriorate. This turbidity removal is carried out by means of the whirlpool.
Cooling & removal cold sludge
The boiled and hopped wort is cooled after the turbid filtration. This cooling is necessary because the later added yeasts can not tolerate high temperatures. The wort must also be aerated, so that the yeast will soon receive sufficient oxygen. Finally, there is a “cold cloudy” (mainly clotted proteins) during cooling.
Alfa uses the plate cooler, which consists of a series of stainless steel plates, through which wort and cooling water are pumped through.
After the wort has been cooled and aerated in the loading compartment, it is pumped to the yeast tank. The fermentation proceeds in two phases, i.e. the main fermentation and secondary fermentation.
The first signs of fermentation come about 24 hours after the wort is started. A fine foam slowly forms on the young beer. Fermentation is the most severe after 3 to 4 days. Then the fermentation gradually decreases. The yeast slowly sinks to the bottom and the high foam layer collapses. The main fermentation is finished after 7 to 10 days, after which the youngster can be “sniffed” to the lower cellar.
The lowering of the yeast only occurs in the fermentation with bottom yeast. In the case of upper yeast, the yeast will settle (above) in the foam deck. That’s the name of the yeast.
Temperature control during the main fermentation also plays an important role. A lot of heat is released during the fermentation. The temperatures may not rise too high. From this it is understandable that breweries could only brew in the winter months. Now the modern brewery is a continuous operation, where depending on the need, it is brewed around the clock.
The theory of fermentation is the following. The wort contains a certain content of malt sugar extract, of which about 80% is fermentable. The fermentation can be divided into two phases, namely the aerobic and the anaerobic digestion phase. The yeast consumes oxygen from the wort for the first one to two days. During this period, the yeast grows and multiplies. When the oxygen runs out the anaerobic phase begins. Now the yeast splits the fermentable sugars into ethanol alcohol and carbon dioxide. At Alfa, this carbon dioxide gas is carefully collected and used again in the process! (natural anti-oxidant)
The secondary fermentation takes place in the lower cellars. This secondary fermentation is not forced at Alfa and lasts for more than 6 weeks, including main fermentation. The purpose of the secondary fermentation is:
ripening of the youngster;
saturation of the beer with carbon dioxide;
clarification of the beer by flocculation of the yeast and protein substances;
make the beer resistant to the appearance of cold turbidity.
After the secondary fermentation, the beer is filtered before being filled. Filtration is effected by means of a so-called kieselguhr filter. Kieselgoer is a porous sandstone that is reduced to small grains.
After the beer has been filtered, it can be filled in a bottle, can or canister. The Alfa Brewery used to fill the bottles by hand, nowadays it has a fully automatic filling line in use, which is capable of filling many thousands of bottles per hour. In fact, the filling machine is a conveyor belt where the bottle undergoes various operations. The return bottle comes in crates, which are automatically emptied. Thereafter, the bottle disappears into a bottle washing machine, where also the labels and the like are removed. After cleaning, with extensive inspection machines on e.g. soil contamination, muzzle errors and the like, the bottle slides over a conveyor belt to the filling carousel. In this carousel the bottle is successively pressurized with carbon dioxide gas, filled with beer and closed with a crown cap. Then the bottle is provided with a label and a separate neck label, the closing seal. Here the unique number is also printed on the back label! The last inspection machine checks for filling height, presence of label and number of bottles per crate.