Mini Brewery System s.r.o.

Průmyslová 4273/3
796 01 Prostějov
Czech Republic

Phone: +420 582 345 186
Phone: +420 582 345 189

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Brewing ingredients

Brewing water

Brewing ingredients Brewing water Malt Hop Brewer‘s yeast Brewing water Important parametres: pH value The pH value of drinkable water should fluctuate between 6 and 8. For brewing purposes pH is set between 6.8 to 7. The creation of pH sediments depends on the reaction of brewing water salts with soluble salts from the malt. water hardness Water hardness is defined by the concentration of calcium and magnesium salts (and theoretically also barium and strontium salts). The proportion of hydrogen carbonates is called carbonate or temporary hardness, because it is removed by boiling when insoluble carbonates and carbon dioxide are produced. Calcium and magnesium salts do not dissolve during boiling processes and therefore these salts cause non carbonate, permanent hardness. cations Calcium and magnesium – create water hardness. Ca2+ influences the stability of ?-amylase, it precipitates phosphoric salts (and thus reduces the pH value) and oxalates. It also influences the flocculation and sedimentation of yeast. Mg2+ is a cofactor of some enzymes. Sodium and potassium – probably influence the taste Metal ions : Ferrum (Fe2+ and Fe3+) takes part in many oxireduction and enzymatic processes. It can influence oxidizing of polyphenols and creation of froth, if the concentration exceeds greatly the limit of 0.1mg/l, it can change the colour of froth to brownish. Mn2+ is an important cofactor of yeast enzymes, however as with ferrum its concentration in water is usually higher then the limit 0.05mg/l. Due to this fact a special process of ferrum and manganese removal is necessary to ensure suitability of water for brewing. Zn2+ stimulates growth of yeast. Other metal inons (Al3+, Pb2+, Sn2+, Cu2+) usually come from the surface of brewery equipment or hop plant herbicides, in higher concentrations they are poisonous and inhibit the enzymatic processes. Copper ions can influence the taste of beer due to their possible interaction with taste distinctive compounds of sulfur. Their bond with sulfur can eliminate free hydrogen monosulphide or ethanethiol. They do not influence the concentration of free dimethyl sulfide, dimethyl disulfide or methyl thioacetate. The ability of copper to bind these compounds of sulfur is prevented by natural chelating agents present in beer, such as polyphenols, melanoidins, organic acids, acrimonious acids and amino acids, and so the compounds of sulphur can influence the taste and smell of beer. anions Hydrogencarbonate HCO3 – they increase the alkalinity fo water Sulphates SO42- - they influence positively decomposition of proteins and lipides. During fermentation they are a source of sulphur dioxide and hydrogen monosulphide. They contribute to bitter, hard or ev en dry taste of beer. Chlorides Cl- - reduce the bitterness of beer Nitrates NO3- - can be recomposed to toxic nitrites


Hop plant is one of the basic brewing ingredients . It brings the characteristic bitter taste of beer and preserves the product. The actual ingredient is a hop cone, dried female blossom clusters which must not be fertilized. Hop plant structure Common hop, Humulon Lupulus L, belongs to hemp family (Cannabaceae). This plant reaches its full productivity in 20-30 years. It is a dioecious plant, it means that there are female and male plants. The hop plant has the following parts: • root system – it is comlex with central part from which fine roots grow up to 6m long • stem – the bine is hollow above the ground, the colour may vary from green to red, it climbs up a wire • leaves – they come out from the nodes, always two opposite each other • lateral sprigs • blossom clusters – it grows on the lateral springs, it consists of 60 blossoms and later changes into a cone • cones – it is green, egg-shaped with a retracted spindle as an axis. False leaves and stipules grow from the spindle and lupulin is produced on their surface during the ripening process. Lupulin is responsible for bitterness and aroma of the hop. The most common cultivar grown in Czech Republic is semi-early red one and other cultivars derived from this one. The most important growing regions are Žatecko, Roudnicko and Ústecko. According to its vegetation-season we can distinguish early, semi-early and late cultivars, the harvest takes three weeks and culminates from 22nd to 25th August, then continues to mid-September. The harvesting can be done either by hand or by harvester. There are two types of harvesters: mobile and travelling harvesters (not available in Czech Republic) or immobile, stationary harvester, where the hop must be gathered first. After harvesting the hop contains 80% moisture, therefore it is dried immediately at 50°C because higher temperature damages bitter substances. Drying process decreases the moisture contents to 10-13%. The hop is hydroscopic; it is sold to agricultural collection centres where it is treated, stored and packed. The storage period should be rather short, with long term storage the quality deteriorates and the hop becomes bitter. Its substances oxidize and change into resins as a result of air, heat and light exposure. In our breweries the hop is used in forms of: • hop essence • granulated hop • pressed hop Hop substances valuable for brewing a. Bitter hop substances – content: 12-22% in dry matter • ?-bitter acid – humulone It is the most valuable substance responsible for bitterness of beer, it is soluble and during hop boiling it passes to the solution in so called isoform. • ß-bitter acid – it affects the bitterness with 1/9 share • ?-soft resin, so called ß-fraction • ß-soft resin ?- and ß-soft resins are lower oxidation products of bitter acids. Fresh hop dry matter contains 3-4% of them, their portion increases during storage • ?-hard resins – the final product of bitter acids oxidation. They are present in fresh hop too, storage and low quality of hop increases their portion. b. Hop tannins – content: 2-6% in dry matter Their importance: • during hop boiling they help to precipitate the proteins in form of tannin-proteinous complexes (flocks), this process is reffered to as 1 o m • they add dark colour to sweetwort, they influenced the taste and bitterness of beer • they affect the amount of cold break which is then removed in whirpool tank. • they decrease the amount of coagulable proteins which has a positive effect on beer stability c. hop oils – content – up to 1% in dry matter In chemistry terminology these are terpene carbohydrides, clear volatile liquid. It vaporizes easily when steam is present, so majority of it evades during hop boiling, but a small portion remains present in the beer and effects its aroma. Hop plant deseases Hop plant contains various microorganisms which are destroyed during the boiling processes, but they influence the quality and preservation of the hop during storage. Hop plant can suffer from primary blights and deseases transferred from the fields. These can be divided as follows: a. viral deseases b. bacterial deseases c. fungal deseases Ad a. • curl leaf desease – it attacts the venation of the leaves, as a result the leaves crinkle • mosaic desease – it attacks palisade cells containing chloroplasts. The chlorophyll is dissolved and thus mosaic on the leaves occurs • hop plant sterility – nucleic acids, the control molecules, are attacked by the desease Ad b. • Bacillus lupuliperda – it attacks damp, badly stored hop Ad c. • Fusariose – decease caused by fungi Fusarium • Hop mildew – Peranospore – parasitic fungus attacking sprouts, leaves, stems and cones • Sphaerotheca humuli – it attacks leaves, stems and cones • Cladosporium and Alternarium • Aspergillus and Penicillium – these fungi develop in the cones, the surface is untouched by the desease. As the hop ripens oxidizing reaction appears, the cones change coulour from green to yellow or red brown. Detecting microorganisms present in the hop plant In order to detect the microorganisms present in the hop plant it is necessary to gather samples of approximately 50 cones in the field, either to a plastic bag or to a sampling bottle. In the laboratory the cones are crushed in a grinding mortar and the amount of 10g is put into Erlenmayer flask tohether with 100ml sterile physiological solution. Then the flask is shaken thoroughly to let the microorganisms loose from the hop. Then 1ml of the resulting liquid is moved to wort agar in Petri dish for an incubation period at the temperature 22-25°C. All colonies which appear in the liquid are analysed and subsequently the microorganisms are identified. Types of analyses performed a. Sensory analyses: Factors for expertise: • hop picking – the cones must be undamaged • appearance, shape, glossiness – high qualty hop is light green in colour and glossy • the appearance of the spindle – it must be refracted • lupulin – it should be golden yellow, sticky • aroma – it should be non-pungent, healthy, clear • cone structure – it should be regular and similar b. Botanical analyses: These analyses define hop damage by all kinds of pests. The analyses are performed by farmers during evaluation and devision of the hop to several quality cathegories. c. Chemical analyses: • moisture content determination – 5g of hop meal is dried at 106°C for 1 hour. Our hop contains approximately 10-13% of moisture. • hop oil analysis – hop oil influences the aroma of beer. Salač-Kotrle method defines the total content of hop oil and its oxidation number. Hop oil contents: Steam is forced through the hop meal and the distillation product is collected to ethyl alcohol. Then the oil is absorbed by active charcoal and subsequently extracted by diethylether. After diethylether evaporation the hop oil is weighed and the hop oil content is defined. Hop oil oxidation number: Nitrogen is forced through the hop meal since it can accumulate hop oil in water. The water solution is then filtred at 0.01 mol. 1-1 KMnO4. The oxidation number is defined as the amount of m1 0.1 mol. 1-1 KMnO4 necessary for oxidation of oil portion extracted from 1g of hop meal. • bitter substances contents – according to Wolmer This analysis is based on the different solubility of bitter substances in organic solvents. By ether extraction all resins are gathered, then they are transfered to methyl alcohol. From this solution we can extract soft resins by hexane, bitter acids are precipitated out by lead(II) acetate and finally the hard resins contant and proportion is calculated as follows: hard resins = all resins = soft resins ß fraction = soft resins = humulone Wolmer index of bitterness: It defines the brewing quality of hop. Wolmer discovered that bitter acids add nine times more bitterness to the beer than ß fraction does. This he expressed in the bitterness index as follows: ß Bitterness index = ? + ------ -9 This formula has been been questioned especially in connection with fresh hop since it underestimates the role of ß fraction – during the ageing process bitter acids oxidize gradually and change into soft resins. Therefore Salač and Dyr have suggested the following formula: ß Bitterness index = ? + ------ 9 Since Wolmer analysis is rather demanding, conductometric measurement of ? bitter acids is used more frequently, because ? bitter acids are the most influential to the bitterness of fresh hop. This method is based on gradual adding of lead(II) acetate solution to toluene extract of hop. After each dose the conductivity of the solution is measured. At the beginning the conductivity does not change because the resulting product consists of non-dissociated lead humulonate. As soon as all the humulone present changes into humulonate, the conductivity curve increases in proportion to the acetate dosing. The equivalence point is then defined from the titration curve. The conductometric value of the original hop is calculated from the total consumption and converted to dry matter values. Another fast analysis method is the spectrophotometry of universal bitterness – samples are developed in organic pectic solution and chloroform is used to define the bitter substance by spectrophotometric analysis.


Another important ingredient for beer brewing is malt. Malt is sprouted and withered brewing barley. It contains enzymes which decompose starch to maltose. Its characteristic features manifest during malting and they depend on the kind and chracter of barley. There are several different types of common malt: • Pilsner (Czech) malt • Vienesse malt • Bavarian malt Further we can distinguish special types with different composition, features and production processes. • caramel malt • colouring malt • melanoidin malt • diastatic malt • proteolytic malt • rH malt Detecting microorganisms present in malt In order to detect microorganisms present in malt it is necessary to homogenize 100 grains and 100 ml of water. Then 1 ml of the result is implanted to germfree nutrient medium – sweetwort – in a Freudenreich flask. The incubation period is 3 days at 22°C. Before the implantation and after incubation period the pH is measured to detect the changes of pH. Then a stabilized specimen is removed to detect contaminating microorganisms. Types of analyses performed a. Sensory analyses: Factors for expertise: • colour of the malt • shape, size and composure of the grain • aroma • taste • damage by pests b. Mechanical analyses • definition of volume density – for malting purposes it should fluctuate between 54-58 kg*hl-l • definition of absolute weight – i.e. 1000 grains – it fluctuates between 30-33 g in dry matter • nature of the endosperm – to detect the texture of the grain by farinator cross section, we distinguish hyaline, semi-hyaline and farinaceous texture • detection of damaged grains and weed seeds • acrospire evolution It is a distinctive feature of different malt types, Czech malt should have the acrospire grown up to 2/3 of the grain length, it should not be overgrown c. Physicochemical and chemical analyses • moisture content determination Freshly withered malt contains 3.5% moisture, the moisture content should not exceed 6.5% after 3 hours at the temperature of 105-107°C • malt extract determination It is the sum of all extractive matters which pass over to the brewing solution during standard decoction process according to conventional method. Extractiveness is essential for dose calculation. It fluctuates between 76-83% in dry matter. • saccharization period calculation It is the period necessary for mash saccharization. It is measured from reaching of 70°C to total saccharization. Pale malt needs 10 to 15 minutes, dark malt 30 to 35 minutes. • drain period determination and purity of sweetwort If the filtration is completed within one hour, the drain period is considered normal. The purity is evaluated after the filtration has finished, the sweetwort should be pure and sparkling. • sweetwort colour determination It is set either by Erant method as consumption of ml I2 0.1 mol. 1-1 or in EBC units. For pale malt it fluctuates between 0.16 – 0.26 ml of solution, for dark malt 0.50 – 1.20 ml of solution. • determination of extract content in starch It is necessary to detect the level of malt modification. In less malt grist there are more extractive matters which can not be decomposed by enzymes. The level of modification can be calculated as follows: extract content in meal minus extract content in malt grist. Standard level of modification is between 2.0 and 2.2%, over 3.3% it is considered low and below 1.3% of high quality. • Diastatic power determination Accordning to Widish-Wolbsch it is set as maltose amount (in grammes) resulting from amylase reactions in 100 g of malt. It is stated in diastatic units WK. For pale malt the amount is 200-300 WK, for dark malt 70-120 WK. • Kolbach´s number calculation It is percental portion of soluble hydrogen from total nitrogen compounds present in the malt. It shows the level of malt modification. High quality malt exceeds 42%, standard good quality malt reaches 36-42%, malt below 36% is not modified enough. • Hartong´s number calculation It shows the level of malt modification. It is calculated from decoction at following decoction temperatures: 20°C, 45°C, 65°C, and 80°C. The resulting extracts are applied to standard decoction process. RE 20°C + RE 45°C + RE 65°C + RE 80°C HN = -------------------------------------------------- = 58.1 4 The figures between 0 and 3.5 show insufficient modification, 5 is an ideal result, 6-10 means excessive modification. • degree of sweetwort filtration acidity The acidity of sweetwort is caused by the presence of organic acids and acid salts, especially phosphoric salts and it influences the enzyme activity. It is detected by two-stage filtration, in the first stage up to pH 7.7 and in the second stage up to pH 9.0. In the first stage strong acids and part of the phosphoric salts are neutralised, in the second stage the weak acids and remaining phosphoric salts are neutralised. The sum total of both phases consumption in ml 0.1 mol 1-1 NaOH per 100g of malt dry matter states the total acidity. The filtration method either used indicators (Luers´s method) or potentiometer. • reducing matters detection The reducing matters in sweetwort are those organic substances which when boiling reduce Fehling\\\'s solution. Their content is expressed as % content of maltose in malt extract. Their detection is performed by Schoorl´s method. This method is based on reduction of Fehling\\\'s solution mixture using I and II reducing sugar in boil. The resultative Cu2O redundance is set by iodometry