What is the difference between homebrew and commercial brewing(equipment)?
Commercial brewing includes Small scale brewing, Pub breweries, Microbrewers, the difference between them and homebrew will be described in detail below.
Small scale brewing
Previously the talk was always about making large volumes of beer in large installations. About 95% of the total global beer production is now brewed by large brewing companies. With their brands they dominate the market and everyone can buy their beers.
However in many countries people increasingly wish to brew their own beer or to sit in a pub and watch how the beer is brewed,experience how it smells and observe what goes on. Of course the beer is always produced using the same stages as have been described for large breweries,but there are a few special features which apply to these small breweries which should be mentioned here. A distinction must first be made between two different groups: on the one hand there are
－ the “home brewers”or "hobby brewers”who brew their own beer and who also drink the small amounts which they produce them-selves,and on the other hand there are
－ the “restaurant or pub brewers”and “micro-brewers"who produce and sell about 1,000 to 10,000 hl per year.
In many countries smaller commercial breweries with a capacity of about 30,000 hl are called microbreweries. There are a considerable number of micro and pub breweries and the number grows daily. In Germany there are about 800 micro and pub breweries with an annual output up to about 10,000 hl,and in the USA and Canada their number has increased in recent years to more than 500.In other countries too, the number of micro and pub breweries being opened is increasing.
What is the difference between pub and micro-breweries? Depending on the legal regulations applicable in the particular country, they sell their beer
－ in the attached eating and drinking establishment (pub breweries, restaurant breweries), or
－ they supply their beer (cask, keg or bottle beer)to restaurants (microbreweries)because they are not allowed to,or do not want to,sell beer in the brewery.
In pub breweries there is a direct connection between beer production and gastronomy. The pub brewer has therefore a very close relation-ship with his customers. The customers of a pub brewery expect
－ to be able to see (and possibly to some extent smell) how the beer is brewed
－ to see the brewer, to talk to him and get to know him,
－ that the beer will taste good and it will be a pleasure to have another glass of it,
－ that the pub will be a comfortable place in which to sit and talk,
－ that there will be a choice of nourishing meals suitable to go with the beer, and
－ that there will be an atmosphere of good companionship.
These are the expectations which a pub brewer must satisfy. And it is not quite so easy for a pub brewer to do this, as wise pub brewers point out. Problems such as the choice of the building for the brewery,the catchment area, the customers to be expected from the catchment area,the status and ability to pay of the potential customers, the brewer's expectations,the type and variety of food to be provided and the serving staff, etc. will not be discussed in detail here. However,an indication will be given of how greatly the answer to these and similar questions can affect the results.
The pub brewer is first of all interested in giving particular emphasis to the display value of his brewery. This includes,for example, an attractive (and as much as possible copper) brew-house, in some cases with an attractive wooden cladding,exhibited close to the public so that it can almost be touched.The two vessels, which it may comprise, should be slightly raised so that everyone can see them.It should be automated, but only when no-one is there,and at other times the brewer should visibly manually control it in person.The fermentation cellar should also be on show-behind glass,of course,for hygiene reasons - with the fermenting yeast head in the open fermentation vessels visible to all. Ever-green plants, such as palms, look good in the brewhouse, but attractive wall decorations must also be present. Here one must have one's own ideas. Everything which the customer sees must stimulate him. High-quality music, a good pianist or a small band which plays occasionally also make a pub interesting and attractive. The brewer can also talk about his beer or how it is made - the customers will be entertained.
What equipment is absolutely essential for a pub brewer and what can he use to complement this? The core equipment for consideration is the brewing plant.
Basic considerations must include the following questions.
－How large is the expected beer trade?
－How many places does the pub have and how many of them will be occupied at midday/in the evening?
－What is the anticipated beer turnover daily,weekly,monthly and yearly?
－How many brews should be made each week?
－What size of vessel does this require?
－What are the possibilities for expansion?
For example: With a 10 hl brewing plant (cast wort output 10 hl) about 8.5 hl of beer can be produced (ca. 15 % loss). If one brew is made on each of five days per week for 40 weeks a year（5 weeks holiday,3 weeks illness,2 weeks repairs) then
8.5x40x5=1,700 hl of beer per year are produced.
If one assumes (with 300 opening days) 6 hl of beer consumption per day this is equivalent to 300x6=1,800 hl of beer per year. It is obvious that in this case there is a deficiency and there are no reserves. However, if a daily consumption of only 4 hl is assumed, then
300 x 4 = 1,200 hl of beer per year are needed.The requirement is covered and a large
reserve is available.
It is of course possible to produce more than one brew a day, but this can not be done indefinitely by one brewer on his own. It is important that the beer production
Process extends into the evening pub trading hours because this considerably increases the entertainment value and the customers feel directly involved in the brewing process.
In contrast to a pub brewer, a microbrewer has fewer worries about the appearance of his brewery. It must of course be clean and attractive but it is not on display to the beer consumers every day. The larger the microbrewery, the more applicable the comments made in the preceding section regarding plant and processes.
However,every microbrewer also needs filling equipment, because his beer is not sold on the spot.Of course there are also microbreweries which operate a pub attached to them.In that case the boundaries between the two definitions are blurred.
First and foremost a microbrewer needs a keg filling plant. Depending on the amount of keg beer a plant with one or more filling heads is required. When the opportunity arises,or when it is necessary, microbrewers also use bottle or can filling equipment.
Because a microbrewer sells his beer off his premises he must lauter and stabilize the beer before it is filled. Moreover he must draw attention to the merits of his product by suitable label-
ling and advertising, because he can not make direct use of the display value of his brewery as a
pub brewer can. But he must also compete successfully against the major brands by establishing a niche with his own special beer brands, which the consumer likes, and convincing his
customers of the quality of his beer. Otherwise everything which is described in Sections 3 to 5 applies also to microbrewers even though the equipment used is rather smaller.
Home brewers（hobby brewers)
The number of home and hobby brewers has increased considerably in recent years in some
countries. This movement is supported by numerous companies which, in many countries, supply the necessary raw materials for beer production in small packages available for purchase and also make available equipment and assistance for wort production and fermentation on the premises of the company. Consequently an individual can make his own beer with minimal outlay.
Others purchase the ingredients but prefer to work with the materials obtained at home and prepare their beer there.
A third group refuse to obtain preprepared extracts and materials and instead are proud to produce a good quality beer by themselves, starting from the beginning. Since the amount of equipment required is relatively expensive to purchase and operate, sometimes groups of such hobby brewers take turns to use a cooperatively bought and operated plant and then compare their products with one another. That is very enjoyable!
In order to make good beer-even in small quantities- good raw materials are required:
－ malt,to be obtained from a brewery or maltings-or home made!
－ hops,preferably as pellets,vacuum packed,from a brewery or a hop merchant.One should try to obtain the smallest possible packets of different sorts - hops are very important for the aroma.
一water, only the local supply is available. But beware-water is usually chlorinated and this produces an unpleasant chlorinated phenol flavour in the beer. It is advisable in such cases to install an active carbon lauter.
－ yeast, this must be obtained in a container from a brewery if a dried yeast is not used,the quality of which can not be guaranteed.Or you can buy a special yeast in a shop.
Turning once again to malt. One can make this oneself. It has been shown (Section 2) how it is produced.But there are a few problems which will be discussed here.
Mashing is the most important process in wort production. During mashing the grist and water
are mixed together(mashed)and the contents of the malt are thereby brought into solution and
the extract obtained.
The transformations during mashing are very important.
-Transformations during mashing
Purpose of mashing
Most of the substances in the malt grist are insoluble. Only soluble substances can pass into beer.
It is therefore necessary to convert the insoluble materials in the grist into soluble materials during mashing.
All the substances which go into solution are referred to as extract.
Examples of soluble substances are sugars,dextrins,inorganic substances and certain proteins.
Insoluble substances include starch, cellulose, part of the high molecular weight protein and other compounds which remain as spent grains at the end of the lautering process.
On economic grounds one attempts to convert as much insoluble material as possible into soluble compounds, in other words to get as much extract as possible. This is shown by the brewhouse yield and the spent grains extract.
However,not only the amount but also the quality of the extract is important, because as little as possible of certain compounds (e.g. the tannins in the husks) is wanted, whereas others(e.g.certain sugars or protein degradation products) are particularly desirable.
The aim of mashing is to form as much extract and as good an extract as possible. Most of the extract is produced during mashing by the action ofenzymes which are then allowed to act at their optimum temperatures.
Mashing is a process of biochemical change. In this process, all possible technical conditions should be provided to maximize the effects of various enzymes in malt. However, the optimal conditions for these enzymes are not completely consistent. Therefore, it is necessary to use their comprehensive advantages to make the wort made to meet the requirements in terms of quality and quantity.
The main technological conditions to be controlled for mashing include the following aspects.
Control of mashing temperature
The mashing temperature can be controlled in several stages
Impregnation stage: The temperature at this time is called impregnation temperature, which is conducive to enzyme leaching and acid formation, and is conducive to the decomposition of β-glucan
Protein decomposition phase: The temperature at this time is called the protein decomposition temperature, and the control method is as follows:
(1) the temperature is lower, the amount of amino acids is relatively larger, the temperature is inclined to the upper limit, the amount of soluble nitrogen is more
(2) For well-dissolved malts, the temperature can be higher, the protein decomposition time can be shorter
(3) For dissolved special good malt, can also give up this stage
(4) For badly dissolved malts, the temperature should be controlled low and the protein decomposition time should be extended
At the above temperature, the internal-β-1,3 glucosin is still active, and the decomposition of β-glucan continues
Mashing stage: The temperature at this time is commonly referred to as the mashing temperature, and the control method is as follows:
(1) During 62 to 65 ℃, the generation of fermentable sugars is relatively large, the proportion of non-sugar is relatively low, suitable for the manufacture of high fermentation beer;
(2) If controlled at 65 to 70 ℃, the leaching rate of malt is relatively increased, fermentable sugar is relatively reduced, the proportion of non-sugar is increased, suitable for the manufacture of low fermentation beer
(3) To control mashing at 65 ℃, the highest yield of fermentable leachate can be obtained
(4) By adjusting the temperature of the mashing stage, the ratio of sugar to non-sugar in malt juice can be controlled
(5) The high mashing temperature is conducive to α the action of amylase, the mashing time (refers to the time of complete iodine reaction) is shortened and generated
The proportion of non-sugar is high
Destrophication phase: At this temperature, α-amylase still works, the remaining starch can be further broken down, while other enzymes are inhibited or inactivated.
So, this is the reason why there are 6 temperature controls on our control system. By this way, it can achieve the best mash effect.
Malt & water mixing system
After the malt powder is dispersed in water, it is adjusted into a non-gramped slurry.
(2) Prevent malt flour from flying, so as not to cause loss and pollution of the environment.
The way the malt and water is mixed
(1) First put water in the mash tank, adjust the water temperature, and then through a feeding tube, the malt powder in the tank slowly into the mash tank, side mixing, side stirring, to prevent clumps.
(2) Use the malt water mixer to make malt powder and water in the malt water mixer before entering the mash tank
Mix first and then into the mash tank. This treatment prevents malt flour from flying and fliving.
In order to achieve this function, we configured a hydrator on the top of mash tun.
After the mash process is completed, the substance dissolved from the raw material in the mash shall be separated from the insoluble wheat malt in the shortest time possible in order to obtain the clarified wheat juice and obtain a good yield of leachate.
The method of lautering
The lauter tank is the most common equipment used in wort filtration at home and abroad. This is a filtration method powered by liquid column static pressure.
Filtration of wort using lauter tanks is carried out through three aspects: screening effect, lauter layer effect and deep lauter effect. The lautering speed is restricted by the following factors:
(1) The pressure difference across the lauter layer;
(2) Permeability of the lauter layer;
(3) The thickness of the lauter layer;
(4) Wort viscosity;
(5) The area of the lauter layer.
The speed, transparency and yield of the wort filtration are greatly related to the structure of the Lauter tun & its accessories.
The tank body of the lauter tank is cylindrical, and the material used was cast iron or copper in the past, but now it is made of stainless steel. The upper part of the tank is equipped with a curved or conical top cover, and the cover is equipped with an exhaust cylinder that can open and close the gate. The bottom of the tank is flat bottom or shallow cone bottom, and a horizontal sieve plate is attached to the upper part of the bottom of the tank. There is a central shaft in the center of the lauter trough that drives the 2~4 arm tiller. The lauter tank needs to have an insulation layer, and the generally used insulation materials include glass wool, asbestos, and organic insulation materials.
For the installation of the lauter tank, the bottom of the tank and the sieve plate must be kept level, so that the thickness of the grains in each part is uniform, which is beneficial to the filtration and washing of the grains.
The effective volume of the lauter tank is about 80%. The height of the grain layer is generally controlled at about 30~35cm (dry crushing) or 40-50cm (wet crushing). If the grain layer is too thin, although it can improve the filtration degree, it will reduce the transparency of the wort; if the grain layer is too thick, it will affect the filtration speed.
(2)lauter sieve plate
The traditional lauter sieve plate is mostly made of brass or phosphor bronze.
0.7~1.0㎡ of interconnected sieve plates are spliced together. Use a milling machine to mill long sieve holes on the sieve plate. The width of the upper part of the screen hole is 0.7mm, and the width of the lower part is 3~4mm, forming a trapezoid between the top and bottom to reduce fluid resistance. The opening rate of the sieve plate (circulation area) can reach 6%~8%.
Most of the new sieve plates are made of stainless steel. Due to the solid pore quality of the sieve plate in Figure 2-5-12, the opening rate can reach 10%~15%. Too high opening rate will not significantly increase the filtration speed, but will Reduce the strength of the sieve plate. The sieve opening should not be too wide, otherwise the solids in the filtrate will increase significantly. The sieve plate is not the lauter layer, but the carrier of the lees lauter layer.
(3)The distance between the sieve plate and the bottom of the tank
The distance between the sieve plate and the bottom of the traditional lauter tank is generally controlled at 8~15mm, which is formed by the feet of the sieve plate. This distance is extremely small, and when the wort is discharged through the wort regulating valve, a suction force is generated, which is beneficial to filtration. However, when some small particles and sludge are accumulated here too much during filtration (especially if the sieve hole is too large, this phenomenon is easy to occur), it will cause the sieve hole to be blocked and the wort flow is not smooth, which affects the filtration.
(4) Wort lauter tubes and lauter holes
Flat-bottomed lauter tanks are evenly arranged in an area ranging from 1.0 to 1.25 square meters-lauter tubes and lauter holes. The location should be such that the leaching range of each lauter hole on the spent grains is neither overlapping nor dead, and should be symmetrical to the position of each sieve plate component. The inner diameter of the lauter tube is 25~45mm, and its free flow cross-sectional area is 5~15c㎡. For the lauter tank with shallow cone bottom, there is only one wort outlet.
After the wort is led out from the lauter tube, for a traditional open lauter tank, the end of the lauter tube is connected to a rotary core wort outflow valve to manually adjust the wort outflow. The wort flow rate depends on the height of the liquid in the tank and the flow rate. When using this regulating valve to limit the flow, no air should enter the lauter system to avoid lautering difficulties. Therefore, a gooseneck elbow is often installed on the wort outflow valve, and the top outlet of the elbow must be 20~50cm higher than the lauter screen to avoid strong suction and air introduction.
(5) Wort delivery system
①Traditional method: Directly lead the mashed mash through the upper part of the top cover of the lauter tank, freely fall or fall down through an annular distributor. This method is easy to cause the separation of the various substances in the mashed mash due to different relative densities, causing some of the quality of the mash. Light sticky substance (mainly protein). It gathers on the upper part of the lees and increases the lautering resistance. This way of guiding people also greatly increases the contact between wort and air.
②Improved method: pump the mash from the bottom of the lauter tank. Pump from the total mash pipe to 2~4 symmetrically distributed mash pipes, and then lead them into the lauter tank. The mash pipes are all located at 1/3 away from the edge of the tank. This way of introduction can reduce the flow rate of the mash, reduce the segregation of the mash, and reduce the contact between the wort and oxygen.
(6) Raker device
The raker device is composed of a variable speed motor, a gearbox, a hydraulic lifting shaft, a raker arm and a raker knife. The raker arm is slow (0.4~0.5r/min) when tilling, and fast (3~4r/min) when discharging. The number of raker arms is determined by the amount of feed, generally when the feeding amount is about 2t It has 2 arms, 3 arms around 4t, 4 arms around 8t, and 8 arms around 16t. The multi-arm raker is to prevent the raker time from being too long. There are various types of raker knives under the raker arm, the distance between them is 20~30cm (determined by the crushing situation, the wet crusher is larger than the dry crushing). This distance gradually increases from the inside to the outside to ensure the evenness of the raker. And wash the lees fully. The lowest position of the tiller blade is 1~2cm away from the sieve plate. When the tiller arm falls at the lowest position, it cannot enter the pit layer. When draining the drain, a separate drain shovel can be used to fix it on the wall of the drain. When draining the drain, it will fall down and be lifted when not in use.
(7) Spraying device for washing grains(Sparging)
The small lauter tank is equipped with a lees-washing water receiver at the top of the shaft of the cultivator. Two horizontal spray pipes are connected at both ends, and the holes are reversed to spray water on the lees layer by using hydraulic reaction. The large lauter tank is equipped with inner and outer water spray pipes in the top cover, and nozzles are installed on the top cover, and the lees washing water is evenly sprayed on the lees layer by the nozzles.
Operation process of lauter tun
Clean the lauter tank, first lay the sieve tightly, and lauter according to the following operations:
(1) Pump the mashed wort after mashing into the lauter tank. The lauter tank is covered with a sieve in advance, and a small amount of 78°C hot water is introduced from the bottom of the tank to the extent that the sieve is barely removed, so as to exclude the sieve and the bottom of the tank. Between the air.
(2) After the wort is pumped into the lauter tank, stir it evenly with a glutinous machine, and then let it stand for 20-30 minutes to sink the lees and form a layer. If the mash is good, the wort on the lees will be like The marble is as pitch black and clear.
(3) At the beginning of filtration, open one or two wort discharge valves in sequence, and then close them quickly to discharge the muddy sediment between the sieve and the bottom of the tank. This operation is repeated several times, and then all the discharge valves are opened slightly. The wort that begins to flow out is not clear, use a pump to pump back to the lauter tank, and after the clear wort flows out, it is sent to the wort temporary storage tank or wort boiling pot, and the lautered wort at this time is the first wort.
(4) At the beginning of the filtration, the wort discharge valve is opened slightly to control the flow rate to prevent excessive suction, which will shrink the grain layer and cause filtration difficulties. The wort discharge valve should be opened gradually according to the flow rate of the wort to keep the wort seeping from the lees layer and the wort flowing out of the drain valve in balance.
(5) After the first stage of filtration, the lees layer is gradually compacted, and the flow rate of the wort gradually decreases. At this time, it should be stirred slowly with a distiller. When turning it, first turn it up from the bottom, and gradually raise the turning machine, so that the lees layer is loosened again and the wort flows out smoothly.
(6) When the first wort flows to reveal the lees, spray 78~80℃ hot water on the lees to start washing the lees to wash out the residual sugar in the lees. This washing wort is the second wort.
(7) Spraying hot water can be divided into 2~3 times according to the washing effect, and the final residual sugar concentration should reach 1.0%~1.5%.
(8) After washing the lees, open the drain hole at the bottom of the lees, and use the lees to drain the lees.
(9) The discharged grains are first placed in the grains storage bin, and then transported to the outdoors by pulsed high-pressure airflow.
The relationship between wort filtration and lees washing and beer quality
(1) The filtered or washed wort should be clear. If it is not clear, it means that it contains a lot of insoluble substances. The content of fatty acids (C6~C18) in the filtered wort is about 4mg/kg, which is about 10 times lower than the fatty acid content in the mash before filtering. Turbid wort contains much higher fatty acids than filtered wort, which will adversely affect the foam and flavor of beer.
(2) Filtration and washing of grains should be carried out quickly to prevent oxidation of polyphenols and darken wort color and poor taste.
(3) The pH value of the lees water should be controlled, and alkaline water should not be used to prevent the polyphenols and bitter substances in the wheat husk from dissolving in large quantities and affecting the quality of the wort. When washing the spent grains, the spent grains should be submerged in the spent grains to prevent oxidation as much as possible.
(4) Washing the spent grains should be carried out carefully. Incomplete washing of the spent grains and the incomplete washing of the extracts in the spent grains will affect the yield; excessive washing of the spent grains will result in a large amount of silicates, bitter substances, polyphenols and other harmful components in the husks. Dissolution is easy to bring flavor and non-biological stability problems to beer; at the same time, it also increases the burden of wort boiling, which is economically unreasonable. Generally, the concentration of the final washing water should be controlled between 1.0% and 1.5%, and special attention should be paid to this problem when manufacturing high-grade beer.
Measures to ensure the filtration rate of wort
(1) The use of high-quality malt, which is the most critical factor, affects the permeability of the filter layer and the viscosity of the wort. If malt dissolves well, feed at low temperature during saccharification, add appropriate amount of β-glucanase to strengthen the decomposition of β-glucan, and reduce the temperature of protein decomposition and prolong the time of protein decomposition for remedy.
(2) Strengthen malt crushing operation. Before the malt is crushed, take humidification measures, or use wet crushing to increase the moisture content of the bark, improve the crushing quality, so that the bark is broken without being broken, so as to improve the permeability of the grain layer and reduce the filtration resistance, which can increase the wort yield. Rate, and can accelerate the filtering speed.
(3) The correct filtration operation must balance the outflow of wort with the amount of wort passing through the spent grains to avoid filtering too fast, especially at the beginning of the filtration stage, due to the large suction force, the grains will be tightly packed and lose permeability. Difficult to filter.
(4) Correct ploughing operation. After filtering for a certain period of time, the layer of grains will gradually shrink. At this time, the grains should be properly ploughed, starting from the bottom of the trough (about 5cm from the bottom of the trough), and the linear speed of the ploughing knife should not be too high. , The linear speed of the outermost tillage knife should not exceed 4min per 1 revolution, and the large filter tank should be controlled at 7~10min per 1 revolution.
(5) The installation of the filter tank should be absolutely horizontal, the inclined filter tank will also make the lees layer tight, and the thickness of the lees layer is uneven, resulting in turbidity and difficulty in filtering the wort.
(6) Strengthen the heat preservation facilities of the filter tank to avoid the cooling of the grain layer and the bottom of the tank, so that the grains shrink and compress and reduce the permeability of the grains.
Reasons for the turbidity of filtered wort
(1) Malt dissolves poorly, saccharification method is not ideal, and protein decomposition is not complete.
(2) Too high filtration speed leads to high wort turbidity, and the filtration speed should not exceed 0.16L/(㎡·s).
(3) Too-thin lees thickness and insufficient wort filtration.
(4) The temperature of the washing grains is higher than 80℃.
(5) At the beginning of filtration, the return wort does not meet the requirements.
(6) Improper operation of the dregs, for example, the dregs are too deep, the linear speed of the tillage blade is too fast, or the dregs is pushed, which damages the dregs layer.
Technical conditions of filter tank filtration
(1) The thickness of the spent grains is 30~35cm (depending on the amount of auxiliary materials added).
(2) The temperature of the saccharified mash is 75~78℃.
(3) The sedimentation of the bad layer requires a smooth surface.
(4) The tank bottom area required for every 1kg of raw materials is 0.5~0.7㎡.
(5) The filtration time of No. 1 wort is 45~90min.
(6) The filtration time of No. 2 wort is 45~90min.
(7) The total filtration time is within 3h.
(8) The temperature of washing grains is 75~80℃.
(9) The pressure difference during filtration is 2~3kPa.
(10) Prevent the temperature of the tank layer and the bottom of the tank from cooling; avoid vibration during filtration.
Wort boiling is a complex process of physical and chemical changes. These changes are intricate and difficult to take care of all the favorable conditions of the changes at the same time. To a large extent, they need to be mastered according to the type of product and operating experience.
(1) The purpose and function of wort boiling
The purpose of wort boiling is mainly to stabilize the components of the wort, and its functions are as follows:
1. Inactivation of enzymes
Destroy the enzyme activity of malt and make it useless, mainly to stop the action of amylase, stabilize the ratio of fermentable sugar and dextrin in the wort, so as to maintain the consistency of wort components and fermentation.
2. Wort sterilization
Through boiling, all kinds of fungi present in wort, especially lactic acid bacteria, are eliminated, to avoid corruption during fermentation, and to ensure the quality of the final product.
3. Protein denaturation and flocculation precipitation
During the boiling process, some proteins that are denatured by heat and combined with tannins to flocculate and precipitate are precipitated to improve the non-biological stability of beer.
4. Evaporate water
Evaporate the excess water in the mixed wort to concentrate the wort to the required concentration.
5. Extraction of hop ingredients
Hops are added during the boiling process of the wort to dissolve the soft resin, tannins and aromatic components contained in the wort to give the wort a unique bitterness and aroma, and at the same time improve the biological and non-biological stability of the beer.
In addition to the above effects, the following reactions were also produced:
(1) Lower the pH value of wort. When wort is boiled, due to the addition of hops, the formation of acidic melanoids, and the acidification of calcium and magnesium ions in the water, the pH value of the wort is further reduced and the wort is promoted. The precipitation of β-globulin in the juice and the decrease of the pH value of the finished beer are conducive to the biological and non-biological stability of the beer.
(2) The formation of reducing substances. During the boiling process, the color of the wort gradually deepens, forming some complex reducing substances, such as reducing ketones, which enhance the antioxidant capacity of the wort, and these substances are essential for maintaining the stability of beer flavor. And abiotic stability.
(3) Steam out bad volatile components
During the boiling process, some of the original and newly formed vapour volatile malodorous components in the wort are steamed out, which also includes part of the bad-flavored hydrocarbon components in the hop oil, such as herringene.
Wort boiling equipment
In order to improve the boiling strength of the wort boiling pot and the utilization of equipment, the modernized wort boiling, in addition to the great improvement of the wort boiling pot, is also equipped with various types of heating devices and auxiliary containers to make the wort boiling method More diversified.
1. Temporary wort storage tank
In order to shorten the feeding time of the wort boiling pot and improve its equipment utilization, when the saccharification batch exceeds 5 batches per day, the filtered first wort is temporarily stored in a wort before entering the wort boiling pot. In the storage tank or wort pre-boiler, to adjust the boiling time of the boiling pot. This equipment also has heating facilities, which can heat the wort to make it close to the boiling point, so as to inactivate the residual enzyme activity (polyphenol oxidase, amylase, etc.) in time. Its volume can hold the capacity of the first wort and slightly rich.
2. Boiling tank
Wort boiling pots have many forms, such as cylindrical ball bottom, cylindrical mouth bottom and rectangular unequal side bottom. The upper part is a spherical or conical cover, a cylindrical vent tube is arranged in the center of the cover, and a switchable gate is attached to the vent tube.
(1) Cylindrical spherical-bottom wort boiling pot The traditional round wort boiling pot has a small volume and its heating surface is made of red copper. It is arranged at the bottom of the pot. There is only a stirrer inside the pot, and some pots are additionally heated. Coil. The pot body and top cover are made of copper plate,
Made of stainless steel or carbon steel plate.
In modern round wort boiling pots, some have the shape of the bottom of the pot (Figure 2~5-28). The heating surface is much larger than that of the spherical bottom, which can promote the convection of the wort and strengthen the boiling strength. This type of pot is also conducive to automatic cleaning. The ratio of the liquid level to the diameter of the round boiling pot is generally 1:1.
(2) Circular wort boiling pot with internal heater. As the capacity of the circular wort boiling pot continues to increase, the proportion of the bottom heating area is relatively reduced. Moreover, large copper pots are not easy to process, so the materials used are developed towards stainless steel.
The thermal conductivity of stainless steel is much lower than that of copper. In order to strengthen the boiling effect and improve the convection of wort, the wall of the stainless steel boiling pot is often equipped with a heating layer composed of semicircular tubes or trough steel. The bottom heating layer and the pot wall heating layer are usually separated, and the steam pressure used is also different. In addition, various types of internal heaters can also be installed inside the pot. There are various types of internal heaters, and the following are mainly introduced:
①Tube-type internal heater: This is the internal heater commonly used in breweries at present.
The inner heater is composed of many heating pipes, which account for 4%~5% of the pot volume. The heating surface is large. The stainless steel production is generally 1.1~1.2㎡/m3 wort, and the evaporation capacity per hour can reach about 10%. The bottom of the pot is curved or cup-shaped. The heater of the cup-shaped bottom boiling pot is installed in the cup, and when washing
The consumption of washing liquid is small.
Using row tube heating, the wort in the tube is heated upwards, and sprays out from the upper part of the heating tube, and the wort at the bottom of the pot continuously enters the heating tube, so that the wort forms a strong convection in the pot, thereby strengthening the heat transfer method and improving the evaporation efficiency , Effectively reduce the scale in the pipe, and can omit the stirring system.
The diameter of the heater should be proportional to the diameter of the boiling pot. If the diameter of the heater is too large, the wort will go up and the heating area cannot be fully utilized; if the diameter is too small, the wort on the outer edge of the pot will not be fully boiled. The solution to this problem is to place a height-adjustable umbrella cover or flat cover on the heater, and guide the boiled wort sprayed from the heating pipe to the outer edge of the pot to produce a good convection effect.
The cleaning time of the heater can be washed once a day or for a longer period of time, depending on the deposited protein fouling. Failure to remove the fouling in time will cause the heat transfer capacity of the heating tube wall to decrease, and even block the heating tube, making it unusable.