Brew beer
Brewing beer is a food-grade process used to make beer . It usually takes place in a brewery and is carried out by brewers .
Basic procedure
overview
The basic procedure most commonly practiced in Europe today consists of the following:
Brewing malt is made from grain (mostly brewing barley ) . The main purpose of malting is to obtain enzymes . The actual brewing process begins with mashing - a fermentation process . The crushed brewing malt is mixed with water. The resulting mash is heated with constant stirring. Mashing is used to convert water-insoluble substances in the malt, especially starch , into water-soluble substances, especially maltose , through the action of the malt enzymes . The mash is then refined in the lauter tun : the spent grains are removed from the wort (this is the name given to the liquid, fermentable part of the mash). By adding hot water, the wort still contained in the spent grains is rinsed out and combined with the wort obtained previously. The whole thing is then boiled with hops in the pan as a so-called first wort . This brew is pumped out of the pan into a whirlpool or through a filter to separate the coagulated protein and other suspended matter from the wort . This process is called knocking out . Finally, the liquid is wort called, cooled in a cooler to the optimum fermentation temperature and depending on the type of beer a culture of matching is yeast added. Top- fermenting yeasts ferment at temperatures between 18 ° C and 24 ° C, bottom-fermenting yeast at 8 ° C to 14 ° C. During alcoholic fermentation, the sugars dissolved in the wort turn into ethanol and carbon dioxide . Some of the carbon dioxide escapes as a gas, and some of it remains in the finished beer under pressure as carbonic acid . After the main fermentation, which lasts about a week, the young beer has to ferment and store for another four to six weeks. The beer matured in this way is filtered again and finally filled into bottles, kegs or cans .
Malt production
Germination and green malt
When malting in the are malting barley (wheat or wheat , as an ingredient for wheat beer at least 50%) for the addition of water germs accommodated. During the germination process, the enzyme amylase , which is necessary for breaking down the starch, is formed and enriched in the grain. After about six to eight weeks of dormancy , in which the reproductive material develops its full germination, it is soaked in soft containers for about two days. The water content increases to around 45% and empty pods and dead grains are floated up. This floating barley is skimmed off. After the switch , the grain goes into the germination box . With a precisely set temperature and fresh air supply, germination begins , which is divided into different phases.
- Phase 1: On the first day of germination, the root germ breaks through the grain. The germination material is now called in jargon crushing pile .
- Phase 2: after three days the root divides. The germination is now called the fork pile .
- Phase 3: Around the fifth day, the roots of the individual grains have grown so far that they interlock. The germination is now called Greifhaufen .
Germination is complete on the fifth day. The result of the germination is called green malt .
Darren
During kilning , the germination process is ended by heating the green malt to 85 to 100 ° C, and the malt dries. Darren is divided into two parts withering and drying . The subsequent color of the finished malt is largely determined during withering because, depending on the water content of the kiln, more starting products are formed for the Maillard reactions that take place later during the drying process. The higher the moisture in the fermented material when it is smoldering, the darker the later fermented malt will be. In the second sub-process, the drying process, the desired degree of drying of the finished malt is set. The malt enzymes are inactivated by heating. Inactivation is gentler with lower levels of moisture.
The result of these processes is the malt . Its properties have a significant impact on the taste of the beer brewed later: Depending on the type of grain processed, the duration and temperature of germination, the water content before the fermentation, and the duration and temperature of the fermentation, very different types of malt are created. For example, the very high temperatures during the drying process result in partially caramelized or charred malt, dark, very aromatic beer with a caramel or smoky taste.
Shot
Grist mill
The malt is crushed ( crushed ) with a grist mill in order to facilitate the later dissolution of the substances it contains in the brewing water. It is important that the husks are preserved. They serve as a filter layer during the lautering process. The rest of the malt should be crushed into semolina and flours . A distinction is made between grist mills with two rollers, four rollers or six rollers and with or without sieving. Furthermore, to improve the husk volume, a conditioning screw with a spacer container can be installed above the grist mill.
Hammer mill
The malt is completely smashed in a hammer mill . The composition of the grist produced by the “hammering” is much finer than that of a grist mill because the husks are “smashed”. Since the natural filter cover of the husks is no longer available, a mash filter is mainly used for lautering .
Mashing
Mashing is the dissolving of malt ingredients in water through enzymatic, physical and chemical processes. The relevant malt ingredients are starch , proteins and cell wall substances . After pre- mashing, the crushed malt is mixed with hot water in a mash tun - the mashing process . Mostly it is mashed at approx. 30 ° C. The resulting mash is brought to temperatures of around 45 ° C. with constant stirring and initially maintained; In the past, the mash crutch was used for stirring . During this so-called protein rest , protein is broken down into amino acids . The temperature in the mash tun is then gradually increased to just over 70 ° C. Meanwhile, the amylase enzyme contained in the malt ensures that fermentable malt sugar ( maltose ) and non-fermentable dextrins (amylaserast) are produced from the grain starch. Do not heat above 78 ° C because this would denature the valuable enzymes .
In this production step, the taste of the later beer is strongly influenced. The choice of brewing water determines the mineral and salt content of the beer. So soft, low-lime brewing water is better suited for tart beers like Pilsener . If one or more upon heating of the mash of 45 ° C to just over 70 ° C detents inserted (that is, periods in which the temperature is not increased, but held at a level between 45 ° C and 70 ° C for a time constant the starch contained in the mash is enzymatically converted into sugar. Resting around 65 ° C (maltose rest) produces more maltose , which is broken down into ethanol in the subsequent fermentation process. Resting around 70 ° C, on the other hand, promotes the formation of non-fermentable dextrins , which are desirable in full-bodied beers. The mashing process is therefore decisive for the type of beer that is created later and takes two to four hours.
In principle, a distinction is made between infusion processes (the entire contents of the brew kettle are heated) and decoction processes when mashing . In the second method, partial mashes are drawn from the container called the mash tun into a mash kettle and cooked there, thereby thermally breaking down the starch molecules. The partial mash is then pumped back, increasing the temperature in the mash tun for the next rest. This procedure is considered to be the original. When the pans in the brewhouse were still being fired directly, it was not possible to set the temperature precisely.
Iodine sample
Mashing is over when the starch is completely split into malt sugar. In order to recognize this, the iodine test is carried out. Iodine is an indicator of starch: a sample of the mash mixture turns dark blue with iodine in the presence of starch. If it does not discolour, the starch is completely mashed (converted to malt sugar). A few drops are taken from the hot mash to sample and iodine solution is added. Since the mash liquid is brownish, a sample is taken on a white plate to better identify it. If the sample turns blue with iodine, the mashing has not yet ended and more time is required for the enzymes to convert the remaining starch into malt sugar. If the sample remains yellowish-brownish, the starch is completely mashed and the lautering can begin.
Purify
The malt can be separated from the wort, i.e. the liquid that is created during the mashing process. The hot brew is poured into a lauter tun. The “self-filtering” property of the mash consists in the fact that malt residues (primarily the husks of the grain) that sink downwards create a kind of malt cake at the bottom of the lauter tun, which serves as a filter layer. Some grains used in brewing (such as wheat) do not have husks. Therefore, barley can be added to support the lautering process. The liquid is slowly drained from the lauter tun into a suitable container, from which the beer should subsequently be made. The brew flows through the malt cake (spent grains cake) at the bottom of the lauter tun, which acts like a filter and holds back the suspended matter from the brew. All solids from the mash are separated out as spent grains, which are mostly used as fodder. The clear liquid obtained is the wort. During the lautering, the wort flow dries up again and again and must be restored using the chopping mechanism of the lauter tun. The reason for this is that the draining wort sucks the spent grains onto the passage slots in the false bottom and the liquid pressure above the spent grains cake ensures more compact sedimentation . The permeability of the spent grain cake is restored by chopping it up.
The term first wort declares the liquid part of the mash that can be extracted from the lauter tun. After the first wort has run out, topping up with hot water takes place in batches or as a permanent addition of water to the lauter tun and is used to wash out the extract (essentially the protein and starch degradation products) from the spent grains that was broken down during mashing . This is where the beer taste is decided: The concentrations of starch breakdown products and malt sugar in the wort change depending on the amount of topping up. This is important for the later alcohol content and the original gravity of the beer. As soon as the extraction is no longer economically interesting, the low-sugar liquid is referred to as smooth water. Re-using this smooth water pays off with stronger mashes, but is associated with disadvantages such as increased tannin content.
There are alternative mashing / lautering methods. For example, a mash filter can be used instead of the lauter tun. The husks - as they are not required as filter cakes - can be separated off beforehand and processed separately during mashing in order to avoid thermally-related taste disadvantages (e.g. tannins) caused by the mash boiling. A later (at least partial) re-supply of an extract from the husks for fermentation is necessary to give the yeast the nutrients it mainly contains, e.g. B. zinc, available. The latter and the emptying / cleaning of the filter are more difficult to automate and therefore relatively complex.
Wort boiling
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The wort is boiled (until it boils ) in the wort kettle or "brewing pan" . Here, hop (originally in the form of hop cones , but more often with increasing industrialization of brewing in the form of hop pellets or extract ) were added and cooked with. When cooking, temperatures of over 80 ° C arise, as a result of which the malt enzymes ( amylase ) originally contained in the brew are denatured and together with other denatured proteins are deposited as hot trub on the surface of the boiling wort.
The type and quantity of hops contribute to the taste and shelf life of the beer. More hops results in a longer shelf life and a tart, bitter taste of the beer. As the water evaporates during boiling, the wort is concentrated to the original wort specific to each variety . At the end of the wort boiling, the original wort is determined using a beer spindle . Before the invention of the brewing pan, heating was done by placing hot stones in the wort ( Steinbier ). The goals of wort boiling include isomerization of the alpha acids present in the hops to iso-alpha acids, lowering the pH value , expelling dimethyl sulfide (DMS), there is a discoloration due to the formation of hydroxymethylfurfural , disinfection of the wort and Adjust to the desired original wort content.
Knock out
Then the undissolved hop components and precipitated protein (together they are called hot trub ) are removed from the wort. This takes place in the whirlpool (formerly in the refrigerated ship ), in which the wort is set in rotation by being introduced tangentially and the sediment settles as a cone in the middle of the vessel. The bare (clear) wort can then be drawn off from the side. This is known as the wort .
cooling down
In a heat exchanger , the clear wort is cooled in a countercurrent process with brewing water and then with ice water to the temperature required for the addition of yeast ( pitch temperature ), gassed with sterile air to saturate it with oxygen and fed into a fermentation tank or fermentation vat. Flotation may take place beforehand . In the production of spontaneously fermented beers , the use of a refrigerated ship is still common. Before the invention of the refrigeration machine, cooling ships were the common means of cooling and turning on the wort.
Addition of yeast and fermentation
Yeast is added as soon as the wort has reached the temperature required for the respective yeast type (between 5 ° C and 20 ° C). This process is known as queuing . The yeast causes the fermentation: In large fermentation tanks, which were previously located in cool and dark fermentation cellars, the sugar in the wort is fermented into alcohol (ethanol) and carbon dioxide within five to eight days . Around 60% to 70% of the malt sugar is converted in this way. The resulting carbon dioxide is sucked off and processed so that it can be added to the beer again at the end of the brewing process (or when tapping).
Fermentation results in bottom-fermented or top-fermented beer, depending on the type of yeast and wort recipe . Today, pure yeasts are mostly added. It used to be communities made up of various yeasts and sometimes bacteria. The composition of these communities depended on the particular brewing environment. Each brewery had its own microflora, which in turn determined the brewing process. The yeast was from either a Hefner maintained and the wort added directly, or the fermentation was left to chance. Random fermentation is called spontaneous fermentation . Even today, spontaneous fermentation is still occasionally used in beer brewing, e.g. B. Belgian beer specialties such as lambic .
storage
The green beer is then hosed into storage tanks , as the brewer says. This is where re-fermentation takes place: the remaining sugar is converted into alcohol. The storage tanks are sealed gas-tight so that the resulting carbon dioxide does not escape and is bound as carbonic acid in the beer. So there is overpressure in the storage tanks. The beer produced in this way preferably has a pH value of 4.5 (some types of beer up to 3.5). The secondary fermentation can take two weeks to three months, depending on the type of beer. Storage gives the beer its maturity and final taste. In addition, cloudy components settle during storage, which makes the subsequent filtration easier.
Filter
In the majority of industrially produced beers, the beer is filtered after storage (formerly a mass filter , now a kieselguhr filter , cross-flow filter , disinfection filter ). The final filtering of protein tannin compounds, hop resins, yeast cells and beer spoilage bacteria achieves a clarity that would not be possible with normal clarification during storage.
Bottling
The beer is then filled into bottles , cans or kegs . For cloudy yeast beers that are industrially filtered, previously killed yeast is added. During the traditional storage in oak barrels , these were sealed and lined with brewer's pitch inside so that the beer did not come into contact with the wood. Filling is now done using the counter-pressure method (with an isobarometer for barrels ) so that the carbonic acid is retained. It is important to avoid the absorption of oxygen, which would impair the quality. The beer is ready and drinkable. However, the taste of the beer will change over time after it has been bottled. On the one hand, this is due to the fact that the ripening processes in the beer continue after bottling , on the other hand, exposure to light and heat trigger processes of decomposition and decay.
The fewer ingredients are filtered out of the beer, the more flavor-defining aromatic carriers remain in it.
Bottle fermentation
With unpasteurized beers, there is another final fermentation process in the beer bottle , bottle fermentation . Since the storage is ended before all the sugar has fermented or the fermented beer is given a "food" (usually fermenting wort in the high curl stage), a residual yeast remains in the beer.
Job description of brewers and maltsters (Germany)
For the apprenticeship brewer and maltster , the apprenticeship ordinance has provided the same content since the 2007/08 apprenticeship year. At the suggestion of the German Brewers' Association and the German Braumeister and Malzmeister Association, the following contents have been added to the training professions: the production of non-alcoholic soft drinks , the maintenance, control and regulation of brewery systems and the operation of dispensing systems ( kegs ).
With an intermediate level of education and at least one year of professional experience, there is the possibility of completing a four-semester training course as a production manager for brewing and beverage technology at the Doemens Academy . At the Technical University of Berlin and the Technical University of Munich ( WZW ) you can study to become a master brewer, master brewer or Master of Science / Bachelor of Science degree. At the Weihenstephan Triesdorf University of Applied Sciences , students with a university entrance qualification can study brewing and beverage technology with a Bachelor of Engineering (B.Eng.) Degree.
See also
literature
- Ludwig Narcissus : demolition of the brewery . 7th, act. and exp. Edition. Wiley-VCH, Weinheim, 2005, ISBN 3-527-31035-5 .
- Wolfgang Kunze : The technology of brewers and maltsters . 9th, updated edition. VLB Berlin, 2007, ISBN 978-3-921690-56-7 .
- Gunther Hirschfelder , Manuel Trummer: Beer. A story from the Stone Age to today. Theiss Verlag-WBG, Stuttgart 2016. ISBN 978-3-8062-3270-7 .
Web links
- Literature on the subject of beer brewing in the catalog of the German National Library
- Small brewing lexicon for hobby brewers and advanced brewers; So for everyone who tries to make high-quality beer themselves
- Instructions, equipment and recipes for brewing beer
Individual evidence
- ↑ Ludwig Narziß , Werner Back: Die Bierbrauerei: Volume 1: The technology of malt preparation , John Wiley & Sons , 8th edition 2012, ISBN 978-3527325320 , p. 1 ( online )
- ↑ Ludwig Narziss, Werner Back: Die Bierbrauerei: Volume 2: The technology of wort preparation , John Wiley & Sons, 8th edition 2012, ISBN 978-3527325337 , ( online )
- ↑ Hagen Rudolph: Home brewing for advanced users . 2nd Edition. Verlag Hans Carl, 2008, ISBN 978-3-418-00789-2 .
- ↑ Andreas Staudt: Selection of a mashing process , braumagazin.de, accessed on November 20, 2016
- ↑ Moritz Gretzschel: Verkocht und zugebrüht , braumagazin.de, accessed on November 20, 2016
- ↑ New subject matter. In: Frankfurter Allgemeine. October 8, 2007.
- ↑ The profession of brewer and maltster: Diverse and full of opportunities , reinheitsgebot.de, accessed on November 20, 2016
- ^ Profile: Weihenstephan-Triesdorf University of Applied Sciences. Retrieved March 25, 2020 .