Martin Hofhuis
Brewing beer for beginners
Theory and practice of brewing beer
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PART 1
THEORETICAL BACKGROUND BEHIND BEER BREWING
Description of the basic ingredients WATER A brewery without water in unthinkable. Most breweries have their own source of watersupply. The water has to be pure, not too hard and without additional flavours. Sometimes, typical for english beers, calcium rich water has to be used to obtain the characteristical flavour. The individual brewer in the Netherlands has good tapwater. If it’s not 100% ok, in most cases something can be done against that. If the water is too hard, you can cook it beforehand to get rid of the excess calcium. To optimize the enzyme action you can add lactic acid to the water, to increase the acidity. Some parts of the Netherlands have a shortage of minerals in the tapwater. This is easily set straight by adding brew salts to the water. The hardness of the water and the minerals have a small influence on the taste of the beer. HOPS Hops is next to yeast the second flavourmaker in beer. Hops give beer a bitter taste and the typical hoparoma. But hop has other effects as well. It enhances the sustainability working as a perservative and it binds excess proteins for filtering later on. Hop is a vine. It grows in the wild on sandy soils of Brabant. Hop has male and female plants. Male plants are not used for brewing beer but we use the flowers of the female plant called cones. The petals of this flower overlap each other and form cavities that contain pollen. Lupulin are yellowish greasy grains that contain aromatic substances (essential oils), hops oil and alpha acid. Hops is cultivated in hop yards and harvested in July/August. Afterwards the hops is dried and compressed into bales or processed into a
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2. GRINDING THE MALT Grinded malt is also known as grist. Proper grinding is an art. Malt has to be grinded into fine granules but the chaffs have to be kept whole. Chaffs are needed during brewing as a filter, during clarification of the wort, after the mashing. To insure this, the grains can best be crushed with a grinding mill. But these mills can be expensive, costing around 250 euros. An iron plate mill costs less but the results are accordingly. The reason for this is that the grains are crushed more roughly to ensure the chaffs stay complete. This leads to a lesser yield. You will need to use more malt for the same amount of sugar resulting into more (negative) flavours in your beer. Like often, it’s all a matter of money. What is the hobby allowed to cost? A handy beer brewer can construct his own grinding mill. Grinding must not be done too long before brewing, if not the flour will be too wet and go sour. Grinding can be done the night before. 3. MAKING THE MASH The actual brewing consists of sugarising the starch in the malt en mashing. using heat. To activate the malt enzymes, we add water to the ground malt, or to put it in a different way, we make a mash. Water conditioning In some cases the water has to be conditioned before use. For instance, to get rid of calcium, it can be boiled. Sometimes brew salts can be added if there are not enough minerals in the water. Its difficult to give general advice on this subject because the quality and the composition of tapwater differs in each community. Water quality and the contents of the water can be requested at your water company.
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concentrate. For the amateur-brewer hops can be bought as flowers or as compressed pellets. Usually two types of hops are used in a brewage: bitter hops to assure enough bittertaste to the beer and aroma hops for flavouring. The amount of bitterness in hops is measured by the amount of alpha acid. Bitterness is indicated by the amount of iso alpha acid. The difference between alpha acid and iso alpha acid is important. Alpha acid does not dissolve in wort. If you want this to happen the hops must be boiled. During that process alpha acid is transformed into iso alpha acid. The latter can be dissolved in wort. In total 40-45% of the alpha acid will be transformed into iso alpha acid. During fermantation, part of this will be lost, so we can say that approximately Âź of the alpha acid will be added to the beer as iso alpha acid. When adding hops to the beer you need to keep this in mind and calculate how much hops is needed ensuring the bitter taste of the beer afterwards. In a brewery people use the term IBU (international bitterness unit). The higher this number, the more bitter the beer. IBU shows how much iso alpha acid in a liter beer. To give an idea of the bitterness of beer: Bitterness levels:
IBU
Not bitter
5-20
Bitterish
20-30 lager beer and palm
Bitter
30-40 stout and certain trappist beers
Very bitter
>40
witbier
beers for the true amateur
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14 Prevent too much aeration of the brewing water.
The brewing water has to be kept oxygen-poor. Too much oxygen in the mash will lead to an oxidised taste of your beer. To prevent extra air being added, you need to add the water to the mash with a hose and the ground malt should be added by scooping carefully. Mixing the mash has to be done with care to prevent extra air being added. Proportion brew water - malt
The quantity of brew water needed to make the mash depends on the type of beer and the amount of malt needed. The proportion varies from 1 ½ to 4 liters water per kilogram malt. This should be indicated in the brew recipe. To brew a lighter beer, usually a thin mash is made using 4 liters of water per kg malt, brewing heavier beers require less water. For instance: The brew recipe, which we discuss in the practical example later on, says to make 20 l of beer using 4,4 kg malt. At a ratio of 3 liters brew water per kg malt we have 4,4 times 4 is 13,2 l of brewing water.
4. MASHING (SACCHARIFICATION OF STARCH) Classification of the types of enzymes
Voor every kind of reaction in the brewing kettle there is a different enzyme available. Seeing there are many kinds of reactions needed, lots of enzymes are active at the same time. Not to complicate the story I will classify the enzymes in categories with those having the same functions. - carbon degrading enzyme - protein degrading enzyme - oxidation-promoting enzyme - structure forming enzyme I hope more can be said later in the course about these different groups but for now I will limit myself to only discuss the carbon degrading enzyme in the mash. There are two important types in this category: alpha-amylase and beta-amylase. Both enzymes have the same properties to convert starch into sugars but do it differently. One is what we call an endo-enzyme the other an exo-enzyme. Exo- means exterior and endo means interior. This prefix indicates the place in the molecule where the enzyme is active. Exo-enzymes are active - Brewing Beer for Beginners -
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For instance a fruit fly that accidenlty is mixed into the mash, infecting it. That’s why it’s recommended to aerate in a closed system using a pump and a duct stone. Make sure it is possible the duct stone can be sterlized or else this can be done using sulphites. The air hose has to be sterlized as well and a sterile filter is placed in the hose towards the duct stone. The stone is weighted, otherwise it will float. One minute aeration per liter of wort is recommended.
9. ADDING YEAST AND PRIMARY FERMENTATION Once the wort is suffciently aerated, the yeast starter or the moistened dry yeast can be added to the wort and the yeast can commence its wonderful job: turning wort to beer. Primary fermentation
The start of the fermentation process is impetuous and involves lots of foam formation. For this reason the barrel for the primary fermentation has to be at least ⅓ larger than the space taken by the wort. As soon as the yeast touches the wort, it senses the sugar and starts division. Initially the yeast will only use sugar to store in its cell as a source of reserve energy. This process can be compared with when a cyclist the night before a race eats lots of starch rich food, needed during his race the next day. After the reserve food is used, the yeast will use amino-acids and vitamines to complete division. At this stage the activity of the yeast is proved by the formation of carbon dioxide, seen as a thin layer on the yeast barrel. As long as there is enough food, the yeast continues its work. Yeast uses its energy in the oxygen-rich phase mainly to reproduce. No alcohol is formed at this moment. When the oxygen is all used up, yeast passes on to an anaerobic phase, meaning anoxic growth. At this stage alcohol is produced together with a huge scale of aromas. The primary fermentation lasts 3-7 days. When ¾ of the fermentable sugars are used, the primary fermentation is over. Because there isn’t enough food for the yeast, most of it will sink to the bottom and the previous foam layer will diminish.
10. THE TRANSFER FOR SECONDARY FERMENTATION Secondary fermentation in a closed barrel
The foam layer that was formed during primary fermentation forms a barrier against bacteria. When this foamlayer disapears, the beer has to be
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7. SECOND LAUTERING: REMOVING THE PROTEIN DEBRIS AND HOP RESIDUES Filtering out the excess proteins and hop residues
After boiling, the wort requires lautering a second time. The residues of the hops and proteins need to be removed. This can be done using various methods. - bucket filter - siphon filter - separate crane As a filter a separation cloth or cheese cloth can be used.
8. COOLING DOWN THE WORT AND AERATION Fast cooling
Once the wort is filtered, it has to be cooled down as fast as possible to prevent bacteria from infecting it. A cooling coil is best used and can be made by any handy man by buying a few meters of annealed copper pipes. Some people use a stainless steal coil from an old beer bar which can be found at a used iron lot. The coil is attached to the tap and water runs down the coil to the sink. A proper functioning coil will have cooled the wort down within an hour, to 25 째C. Not every beginner will have an elaborate gamma of tools, so one can make use of the bathtub, a shower or just the outdoor air. In this case good hygiene is necessary to prevent infection by bacteria. Aeration
What needed to be avoided in previous steps, i.e. too much contact between wort and air, has to happen now. When the wort is cooled to 25 째C, it needs to be aerated. Yeast needs oxygen in order to grow and will develop too slow without it. Aeration can be done by using various methods. The most simple method is using a disinfected saucepan and scooping up part of the wort to let it gently flow back to the mash. This has to be repeated as many times as there are liters of wort. There is huge danger to this method.
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protected in a different way against infections. This is achieved by closing the barrel with an airlock so there is no contact with air. The beer has to be transferred to a jerry can or carboy that has an airlock for secondary fermentation. The airlock should be filled with sulphite. This allows carbondioxide to escape but no bacteria or dust can enter. The secondary fermentation lasts 1 - 3 weeks. After that, the beer is ready to be bottled.
11. BOTTLING THE BEER Under hygienic conditions the beer is transferred to the bottles with a siphon. During bottling a small amount of sugar is added to the beer, this will serve for fermentation in the bottle and help form carbon-dioxide. The bottle is closed with a cork, u-lock or a crown cap. 12. FERMENTATION IN THE BOTTLE AND MATURATION In about a week carbon-dioxide will form in the bottle. The bottles are placed somewhere warm. After this, the beer has to be stored a couple of weeks so it matures. After bottling aromas will continue to form and the so called taste changes take place. After a few weeks to months, depending on the type of beer, it is ready for bottling. Thus far the theory of beer brewing. Before we continue with the practical part, first some information about disinfecting the tools.
13. DISINFECTING THE TOOLS Disinfection can happen using different methods: - disinfection by heating - disinfection by chemicals Disinfection by heating
Heat is the best way to kill bacteria. With a temperature of 75 °C most bacteria will die. Using heat to disinfect is also called pasteurization and is used for milk and other nutrients. A better method to kill bacteria is by boiling, that will kill all the bacteria. Half an hour at 100 °C in sufficient to ensure all bacteria are dead. Sterlization, killing not only bacteria but also their spores, is done by heating under pressure. This is called autoclaving. Brewers usually don’t use this last
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STEP 3. MAKING THE MASH The ground malt is mixed with warm mash water. • take 14 l mash water and heat to 54 °C , or take warm water from a boiler. Let the water run slowly into the pan. This way no extra oxygen is added. • add the ground malt to the warm water and stir to prevent lumps being formed. The temperature will decrease a few degrees. • heat to the desired temperature if necessary. STEP 4: MASHING • mashing is done in 3 steps • protein rest • first sugar rest • second sugar rest Protein rest
After adding the malt the temperature decreases. • Reheat the mash to 52 °C if necessary. Stir well, keeping an eye on the temperature. • Keep at this temperature for 15 minutes. Stirring during the protein rest is not necessary. • When using a smaller pan the warmth can be trapped by wrapping the pan in an insulating blanket, for instance a sleeping bag. With bigger quantities reheating from time to time will be necessary. Controling the pH
After the protein rest it is wise to measure the acidity or pH. This should be 5,5. The amount of acid needed to correct the pH depends on the acidity of the mash water and the malt. Be careful when adding it, because it is easier to add acid than to get rid of too much acidity. To check the pH there are strips, sold in pharmacies, based on a colourscale. First sugar rest
During the first sugar rest the mash has to be heated to 62 °C (not warmer!) Do not let the temperature rise too fast during mashing. The speed of the temperature rise may not be faster than 1 °C per minute. • During this rest the starches are broken down to multiple sugars. Keep the temperature at 62 °C for 45 minutes. - Brewing Beer for Beginners -
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BREWING BEER IN 12 STEPS STEP 1. PREPARING THE YEAST Dried yeast
The easiest way to add yeast is by using dried yeast. Right at the end of the brewing process the yeast can be prepared. The instuctions are easy. The content of the bag of dried yeast is poured into a cup of warm water (37 °C). The dried yeast will then absorb water and start to ‘live’. As soon as the wort has cooled down the yeast can be added and will start to reproduce. Liquid yeast
Using liquid yeast requires preparation beforehand. Today yeast is sold (Wyeast) in a capsule with oxygen rich wort in a foil bag. A few days before brewing, the capsule has to broken and the yeast and oxygen rich wort will mix. Yeast will reproduce producing carbon dioxide. Thanks to the carbon dioxide the bag will expand, this is a sign the yeast is active. On the morning of brewing, the yeast from the bag has to be added to 1 liter of sterilized wort. This is what we call: making a yeast starter. Other methods of cultivating yeast will not be explained in this book, given its limited character.
STEP 2. GRINDING THE MALT Good grinding is important in order to obtain a clear filtrate. We need a sieve formed by the husks of the grain. The main idea behind the grinding is to keep the grainhusks as in tact as possible whereas the endosperm has to be ground as fine as possible. Properly ground meal consists of ⅓ fine flour ⅓ part flour and ⅓ part pieces. If using only fine flour filter problems will arise. Grinding does not happen too long beforehand given the fact that malt spoils pretty fast. One night beforehand is the limit. In shops there are many types of grinding mills, the rolling mill gives the best result. - Brewing Beer for Beginners -
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Appendix 1 Specific gravity, alcohol percentage and yield As brewers we want to know if the brewing process delivered the same amount of fermentable sugars like the recipe intended. For this we need to make some calculations. We need to know how much sugar the brewing process yielded. Because the sugars determine how much alcohol is formed, more sugar means more alcohol and aromas. • The beer we are brewing is made with 3600 gram pils malt and 200 gram amber malt and 200 grams of cara pils malt. Giving a total of 4000 grams of malt. • From the malt we can gain 75% sugars. 75% of 4000 is 3000, so we can yield a maximum amount of 3000 grams of sugar using 4 kg malt. Containing both fermentable and non fermentable sugars. • Of the total amount of sugar, 65% are fermentable sugars and can be transformed to alcohol, 65% of 3000 grams is 1950 grams. So the total sugar amount consists of 1950 grams fermentable sugars. • Of these fermentable sugars, half will form carbon dioxide the other half alcohol. 975 grams of sugar can be formed from the wort (in 20 l). The other half is gas and will escape. • Per liter beer: 975 ÷ 20 = 48,75 grams alcohol. But, per liter = per 1000. If we want to know the alcohol percentage in the beer, we divide by 10, again meaning 100 ml wort with 4,875 gram alcohol = 4,875. Because alcohol is lighter than water (80%) we multiply the weight of the alcohol by 10 and divide by 8, giving 6,09 volume procent. In the above calculations we take the maximum yield into acount. For this reason we better use a comparison table for the specific density, giving us the yield of our brewage. Determining the specific density
The specific density is measured with a hydrometer. Useful for measuring the weight of liquids, containing soluble products. In our case water with sugars dissolved. The more sugars are dissolved, the higher the glas bobber will float.
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should contain 250 mg iso-alpha-acid if the bitterness is 25 IBU. We accept that 150 mg are delivered by the bitterhops and 100 mg by the aromahops. When we divide the right amount per 10 liter by the amound per gram hops we should get the right numbers for the use of these two hop types. For bitterhops 150 รท 16,25 = 9, 23 and for aromahops 100 รท 8,75 is 11, 42 grams. We will use round numbers to weigh in grams and use a gramweighing scale (letter scale). Recalculating the hops using a different alpha acid %.
When I use hops this year of 5%, the following year the strength can easily be either 6% or 4%. In that case divide the strength of the following year with the strength of that same year and multiply the result with the amount of grams indicated in the recipe. For example: in our recipe 20 gram hops 5% and your hops is 6%. 5 รท 6 = 0,83 times 20 is 16,6 grams.
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44 Estimating the alcoholpercentage
Not all the sugar is fermentable and that part will not be transformed into alcohol by the yeast. For this reason it is not possible to determine beforehand how much alcohol the beer will contain. Column 4 shows the minimum amount of alcohol you can achieve. Column 5 the maximal amount and column 6 the average amount. Using our example this means 5,6% - 7,5% - and 6,5 %.
Appendix 2 Hops calculations Calculating the bitterness of the hops
The substance that adds the bitter taste to beer is iso-alpha-acid. This substance is formed by boiling alpha-acid. The yield of alpha-acid is rather low. Only ¼ will be transformed into iso alpha-acid. Furthermore the yield depends on the boiling period. One should boil the beer at least on hour to achieve the right amount of bitter aromas. The alpha-acid in hops is expressed in percentages. Seeing we convey the bitterness in mg (1 IBU = 1 mg iso-alpha-acid per liter beer) we convert percentage to mg. 1 gram hops = 1000 mg. When using hops of 6% this means 6 per 100 or 60 per 1000. Hops of 6% contains 60 mg of alpha acid. Within a normal yield, 25% will remain as iso-alpha-acid in our beer. 60 ÷ 4 = 15 mg. If we want to produce a beer of 25 IBU (25 mg iso-alphaacid per liter) and our hops contains 6% we will need 25 ÷ 15 = 1, 66 grams of hops per liter beer. Brewing 10 liters we multiply by 10 leading to 16,6 grams of hops. Given the strength of the hops differs between harvests, the ratio has to be recalculted often. In the end, wort with a high specific density will absorb less iso-alpha-acid than that with a low specific density. Calculating this we need to use a correction factor that won’t be explained in this book. Calculations in our recipe of Brabants ale.
The IBU ( bitterness unit) of the beer we will brew is 25. Giving 25 mg of iso-alpha-acid per liter beer. We used two types of hops. Bitterhop of 6,5% and aromahops of 3,5%. This leads to 65 ÷ 4 = 16,25 mg and 35 ÷ 4 = 8,75 mg iso-alpha-acid per gram of hops. 10 liters of beer (the amount used in standard recipes)
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