Lecture 1- Introduction to Brewing notes 2021.pptx

INTRODUCTION TO BREWING Dr. Brian Freeland [email protected] DEFINITION OF BEER Beer is an alcoholic drink made from yeast fermented malt flavored with hops BREWERS MAKE W O RT , Y E A S T MAKES BEER YEAST AND BEER - BASIC YEAST METABOLISM • Definition: Metabolism is the chemical processe...

INTRODUCTION TO BREWING Dr. Brian Freeland [email protected] DEFINITION OF BEER Beer is an alcoholic drink made from yeast fermented malt flavored with hops BREWERS MAKE W O RT , Y E A S T MAKES BEER YEAST AND BEER - BASIC YEAST METABOLISM • Definition: Metabolism is the chemical processes that occur within a living organism in order to maintain life. BASIC YEAST METABOLIS M • Mass Balance* for Beer Fermentation • Mass Balance is a term used in comparisons of the inputs and outputs of processes. ETYMOLOGY OF THE WORD ENZYME leaven (n.) mid-14c., substance added to dough to produce fermentation, YEAST METABOLISM REVIEW • Respiration: • Fermentation: BREAK View links you tube links on LOOP - Biochemistry OVERVIEW SIMPLE PROCESS ! Fermented malted cereals from 1500-1300 BC onwards DCU GRADUATES BREWING IN IRELAND! DCU BT graduates have started brewing companies! DIFFERENT TYPES OF BEER DIFFERENT TYPES OF BEER DEFINITION OF BEER HOMEBREWING TO START WITH… THE “SIMPLE” HOMEBREW PROCESS 1. Grist production • Crush malted barley to form a course flour. THE “SIMPLE” HOMEBREW PROCESS 2. Infusion & mashing • Malted barley is soaked in hot water to release the malt sugars. • Adding warm water to the grist to form a porridge-like mash. Malt enzymes are encouraged to solubilise the degraded endosperm of the ground malt. • Separating in a suitable vessel the aqueous extract, called wort, from the spent solids by spraying further supplies of hot water onto the mash. BOILING & COOLING 3. Boiling • The malt sugar solution is boiled with Hops for seasoning. • Boiling the wort with hops. • This stops enzyme action, sterilises the wort, coagulates some proteins; • the hops impart distinctive flavours and aromas to the wort. 4. Clarifying, cooling and aerating the wort • so that it is an ideal medium for yeast growth and fermentation. FERMENTATION AND MATURATION 5. Fermentation • The solution is cooled. • Yeast added to begin fermentation. • The yeast ferments the sugars, producing ethanol, releasing CO2 and ethyl alcohol. • Other yeast metabolites contribute to flavour and aroma. 6. Maturing and clarifying the beer. 7. Filtration and bottling • When fermentation is complete, the beer is bottled, sometimes with added sugar to provide the carbonation. MANUFACTURING PROCESS http://www.szentandrassorfozde.hu/en/tartalom/brewing-process, accessed 1st March 2016. TIMELINE – BREWDOG BREWERY IMPORTANCE OF HOPS • Adds bitterness and flavour. • Native of Europe. • Provides some anti-microbial protection. • Helpful for good foam formation. • Alpha Acids in hops creates bitter taste. • Insoluble in water until after boiling. Type of beer Geographical Average Area bitterness (IBU) Lagers Pale Ales Stouts N. America 12-20 Germany 26-28 N. America 14-18 U. K. 24-28 Ireland 36-45 U. K. 20-30 BITTERNESS LEVELS – LOCATION LOCATION LOCATION…. TASTES? – COFFEE FL AVOUR WHEEL Tune your beer ! OTHER INGREDIENTS? German beer brewed according to the “Reinheitsgebot” • Only ingredients: • Hops • Barley/wheat-malt • Pure mineral water FINAL BEER ANALYSIS Typical measured parameters • Alcohol Content by GC. • Specific Gravity. • Bitterness. • Haze Stability. • Beer Colour. • pH. OPEN SOURCE RECIPES ! THE HOMEBREW KIT… GO EXPERIMENT ! https://www.brewdog.com/lowdown/blog/diy-dog THE MALTING PROCESS THE STRUCTURE OF GRAIN • The embryo – containing end is attached to the rachis. • The main tissue of the grain is the dead and non-respiring starchy endosperm (this serves as the seed’s foodstore). This tissue is made of thin cells packed with starch grains embedded in a protein matrix. • In section the starch endosperm of good malting barley appears white and opaque, “floury” or “mealy”. This is due to small air filled cracks in the materials around the starch grains. • In contrast poor quality grain appears greyish and translucent called “vitreous” or “glassey” or “steely” in appearance. • *A combine harvester that reaps, threshes and cleans (winnowing is the separation of the grain from the chaff) in one operation. THE STRUCTURE OF GRAIN • The Aleurone layer is about three cells thick and almost completely surrounds the starch endosperm . • These cells have thick cell walls and respire (they are living cells). This layer plays a major role in producing the hydrolytic enzymes which are essential during malting and subsequently during mashing. • The husk and pericarp ensure that water is rapidly distributed over the surface of the grain by capillarity so that the embryo easily becomes hydrated and may germinate. • The testa prevents the outward diffusion of sugars, amino acids and other low molecular weight nutrients form the interior of the grain. Any damage to this layer during harvesting or handling will reduce the viability of the grain and its suitability for malting • Resting phase for barley after harvest. • Although viable grain will not grow. • Barley must be recovered from dormancy before it is steeped. DORMANCY • Assessed by the 4ml test (Germinative Energy). • 100 corns, dorsal side up on filter paper in a petri dish. • Add 4ml water, incubate for 72 hours, check and remove growers every 24 hours. • Result = % GERMINATIVE ENERGY. • Must be > 95% before barley is steeped. • Must ensure that the barley is alive (or viable) before it is steeped. • Checked by calculating Germinative Capacity of barley. • Peroxide Test. VIABILITY • 100 corns steeped in solution of hydrogen peroxide for 72 hours. • Remove growers every 24 hours. • Result = % GERMINATIVE CAPACITY. • Must be > 98% before barley is steeped. BARLEY WATER SENSITIVITY TEST Water sensitivity relates ability for grain to germinate in an excess of water Can occur when barley is viable and mature. Exposure to too much water will result in drowning. Measured using 8ml test. Same as 4ml test, but use 8ml water ie excess water. < 85% indicate water sensitivity. Overcome WS by using a short first water and as long a first air rest as possible. After moisture content has been increased, the barley will behave as normal. THE MALTING PROCESS STEEPING PROCESS • Steeping is the first stage of the malting process. • It lets the seeds seep in enough moisture content by weight to sprout. • Two sub-stages: • wet steeping • air rests. • The kernels are steeped in cool hard water so that the seeds begin sprouting. • The moisture content in the barley is checked, to make sure that it has taken about 42-46% moisture by weight, the water is then drained and the grains are put to rest. • This is called an air rest. The moisture content in the malt will determine its color. The more the moisture content the darker is the extraction of the malt. • It is also the most critical. • Selection of the correct steeping regime is essential for a good final product. MALTING 1 • The first part of this process is the malting step. • Malting has the purpose to trick the grain in order for it to grow. • This is done by steeping the grain in water for two days and allowing it to germinate for another five days in drier conditions. • During that phase the starch (present in the endosperm of the grain) is made more available and several enzymes (α & β amylases, β-glucanase…) are synthetized in the grain membrane (Aleurone). • At last, the grain is kilned at a temperature range of 50 to 90°C to: stop the germination, dry the grains and enable the colour development (Maillard reaction). In addition, a large quantity of proteins is hydrolysed in smaller peptides making it more soluble. [7], [8] MALTING 2 • Malting will lead to very different products depending on how the process parameters are varied. • Steeping and germination temperatures, percentage humidity, duration and aeration cycles must be carefully chosen to have an efficient modification of the grain (breaking of the cells walls for starch release). • Kilning efficiency will depend mainly on the humidity level and the temperature of the process. • As a rule, the more the temperature is high the more the colour (from pale yellow to dark brown) and flavour are developed, and if the moisture of the grain is high, it will develop a more “toffee” flavour, usually those malts are called caramel malts. [8] GERMINATION AND KILNING PLANT CHANGES THAT TAKE PLACE DURING MALTING COMPONENTS OF MALT SUPPLEMENTIN G THE MALT GRIST To change the colour or flavour of the beer To improve quality (wheat for foam, alter mouthfeel, reduce potential haze formation) Increase the capacity of the brewhouse •Reduce production costs Improve brewhouse yield ADJUNCTS AND COLORED MALTS Categories: • Malted Cereals • Processed Cereals • Unprocessed Cereals • Sugars and Syrups ADDITIVES 1: MALTED CEREALS AMBER MALTED BARLEY WITH ADJUNCTS ADDITIVES 2: PROCESSED CEREALS Malted Wheat • Used as the main CHO source in wheat beer. Can be used up to 50% of the grist. Contributes to wheat beers’ appearance colour and flavour Torrified Wheat • Produced by heating the moistened but unmalted cereal. The internal structure is ruptured so that the starch is released so that the starch is accessible when it is mashed in the brewhouse. Can be used up to 10% of the grist Wheat Flour • This is milled wheat in which separates the starch from the embryo. It can be used at 10% of the grist. ADDITIVES 2: PROCESSED CEREALS • Maize Grits • Produced by milling the maize and at the same time removing the germ (embryo) which contains protein and oil. Maize grits must be cooked in a cereal cooker in the brewhouse in order to gelatinize the starch. Maize grits are cheaper than malt and can reduce costs. • Maize Flakes • Maize flakes are produced form maize grits by passing them through a hot roller which gelatinizes the starch and makes it accessible to malt enzymes. Rice • Used in the same way that maize is used. Both grits and flakes can be used. Both the grist and the cold rolled flakes required cooking before being added to the mash. Steam (hot) rolled rice may not need cooking in a cereal cooker if the heat treatment has gelatinized the starch. Oats ADDITIVES 3: UNPROCESSED CEREALS • Can be added to the mash (the oat starch has the same gelatinization temperature as barley starch). Oats impart a smooth silky texture to stouts Rye • This is associated with German Roggenbier. It can be added as malted rye or unmalted rye to the mash conversion vessel. Rye increases full palate, and a crisp slightly spicy flavour Barley • This is added to Guinness stout as an adjunct. Sucrose • Mostly used in liquid form. Highly fermentable and is usually added to the kettle. Can be used to increase the capacity of the brewhouse . Can be used as a priming sugar for secondary conditioning Invert • This is hydrolized sucrose. It can be a solid or liquid. Used for the same reason as sucrose ADDITIVES 4: SUGARS Glucose • Produced by hydorlysing starch – used in the same way as sucrose Lactose • This is unfermetable milk sugar. It is added to milk stouts for its texture High Maltose and High Maltotriose syrups • Produced from starch. Can be used to modify the characteristics of wort Caramel • Dark burnt toffee flavoured liquid. Can be used to adjust beer colour STAGE IN PROCESS FOR ADDITION OF ADJUNCTS • Adjunct are introduced into the process at 3 different possible stages • Cereal Cooker – start of mash • Mash Conversion Vessel (MCV) • Brew Kettle USE OF A D J U NC T S 1: C E RE A L C OO K ER - STA RT O F M A S H • Unprocessed adjuncts generally contain starch in an unrefined form. • grits, flakes, dry grains or starches. • Before starch can be broken down to simple sugars (by enzymes) the starch molecule must be made accessible to the enzymes. • This is done by gelatinisation of the starch with heat. • like making white sauce for corn-starch. USE OF ADJUNCTS 2: MASH C O N VE R S I O N V E S S E L • If the adjunct is pre-gelatinized (has been heat treated) • or if the gelatinization temperature is the same or lower than that of barley. • Then the adjunct can be added to the Mash conversion vessel. USE OF ADJUNCTS 3: BREW KETTLE • Simple sugars (which yeast can ferment i.e. convert to alcohol) can be added to the kettle (the readily dissolve in the hot wort) – a bit like adding sugar to a cup of tea! NEXT LECTURE… MILLING AND MASH CONVERSION 1. Milling • The malt is crushed 2. Mashing 3. Conversion • Crushed malt is mixed with water to start the conversion process • The starch is converted into sugar by the malt enzymes. FINISH