Homebrewing beer
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[edit] Beer
The beer brewing process can be broken down into the following steps:
- Making wort;
- Fermentation;
- Clarification;
- Conditioning;
- Packaging (in bottles, kegs or casks);
- Consumption.
The principles behind the process of homebrewing beer are similar to commercial processes except in scale. A hopped wort is produced and yeast pitched into the beer to stimulate fermentation. The complexity of the process is mostly determined by the approach used to manufacture the wort; by far the simplest method is kit brewing.
[edit] Liquor
Perhaps the most important ingredient of beer is water. In all but the simplest of brewing processes, this is treated by boiling to sterilise the liquid and to help drive off any dissolved chlorine. The resulting purified water is known as the brewing liquor. More serious homebrewers contact their local water company to obtain a report on the dissolved minerals in their water. (This can be done free or for a nominal charge in the UK and the US).
Some brewers will employ water treatments to try and improve the quality of their water. This process is known as water treatment or sometimes burtonisation[1] after the famous Burton brewery in the UK. A simple, but effective water treatment technique is to add a Campden tablet, (Sodium / Potassium MetaBiSulphite), tablet to the water prior to boling it. This helps force out the chloramines added to domestic water supplies to ensure that their chlorine content remains stable.
[edit] Kits
Sometimes known as beer in a can, no-boil, and hopped wort; kits contain liquid malt extract that, when reconstituted with water, produces wort. They are the easiest method available since the basic varieties typically don't require boiling or other preparations. Generally, the quality of beer from these kits can be on par with beer made from all-grain or malt extracts, and can be a good start for someone overwhelmed by the process. Kits requiring additional sugar tend to produce thinner beers. These "sugar" kits typically come in one 1.8Kg[2] can.
Some more authentic kits contain extra malt extract and come in two cans weighing a combined 3Kg.[3] A few advanced kits may also come with a hop teabag and require you to boil this with the wort before cooling it and pitching the yeast. On the whole two-can kits produce thicker-tasting, more commercial brews as all the alcohol is made from malt sugars. Some learners try a few of the more complex 3Kg kits to get used to the copper hopping, (boiling wort with hops), process before progressing on to more complex brews.
[edit] Extract brewing
Having mastered kits, homebrewers can experiment with their own recipes by boiling water, malt extract and hops together in a large kettle or boiler; then cool the resulting wort before fermenting. The primary advantages of extract brewing are:-
- the ability to select malt extracts and spray, (dried), malts that affect the colour, richness and flavour of the final beer; and
- selecting which hops to use affecting the level of hop flavour and dry-taste to the beer; and
- using dead, (heavily or hard roasted), malts - crystal malt, black malt and roasted barley to add colour and flavour; and
- experimenting with brewers sugars and syrups to affect the final strength of the beer.
Extract brewing still saves considerable time against any mashed brewing processes; an extract brew can be completed from start to finish in around two and a half hours. As such it remains a popular home-brewing method.
Brewing liquor is added to malt extract and then boiled with hops and any added dead malts for one or two hours depending on the recipe. Hops may be added at varying stages, typically at the start of the boil and after 75 minutes to control the overall flavour.
Boiling wort, whether from mash or extract, provides a number of advantages to the final brew:-
- driving off undesirable volatile substances produced during the extraction or mashing process;
- coagulating proteins and nitrogenous compounds, (this is particularly important for mashed beers but can be important for some extracts);
- allowing the wort to be rapidly cooled to force both hot and cold protein breaks, (the settlement of coagulated compounds).
Many hazes in beer are caused by the accumulation of proteins in the wort; a vigorous boil will improve the clarity of most beers. Many modern extracts are have already been treated heat or chemically treated, however a good boil will reduce the risk of a hazy beer and also assist the absorption of flavours from both hops and dead malts.
Many homebrewers achieve excellent results with extract recipes. Boiling a quality extract with hops can produce good facsimiles of many classic brews. However, some brewing adjuncts, (other grains added to beer), need to be converted by enzymatic reactions involved in mashing to be useful in brewing; therefore some homebrewers use a method called partial mashing
[edit] Partial mash
A partial mash differs from an extract brew in that the extract remains enzymatically active. Unlike dead malts where some of the starch has been converted to sugar via the action of heat and the natural enzymes have been destroyed, wheats and unmalted extracts need the help of enzymes to convert their starches into sugars. In a full mash these enzymes are naturally present in the mash. Diastatic malts replicate this process.
The next step up from extract brewing is to use a diastatically active malt extract to convert starches from other beer adjuncts; such as flaked and torrifed barleys, flaked wheat and wheat flour into fermentable sugars. These extracts are currently only available in the tinned form. The extra advantages of this method are:-
- A broader palette of ingredients to choose from;
- Unmalted barleys and wheats add extra "body" to a beer;
- Dead malts may still be added to the overall recipe.
Partial mashes are also popular amongst extract brewers as they do not require any investment in mashing equipment and add only a short time to the wort preparation process. To use the enzymatic reaction, the wort is kept at 66°C for 30-45 minutes in the boiler before slowly raising the temperature to 75° to stall the reaction. The wort is then boiled as usual. Having spent this extra effort on a brew, most enthusiasts invest in a secondary vessel to clarify and part condition their beer.
[edit] Full mash
Advanced homebrewers make their own extract from crushed malted barley (or alternative grain adjuncts such as unmalted barley, wheat, oats, corn or rye) by mashing the grain in hot water. This requires an insulated vessel known as a mash tun.
When mashing beer there are two competing enzymatic reactions at work. α-amylase is working to convert malt starches into dextrins adding body and residual sweetnes to the beer, whilst β-amylase is working to convert malt starches and some dextrins into sugars for making alcohol. Both reactions work their best at differing temperatures and mash pHs, (acidity). Mashing is a trade off between these reactions. α-amylase prefers a temperature of 70°C and a ph of 5.6. β-amylase prefers a more acidic pH of 5.0 and a temperature of 60°C. Hence the compromise choice of 66°C, although professional and home-brewer alike may vary mash temperature and pH to obtain differing results. Broadly, the hotter and more alkaline the mash, the drier and more alcoholic the final beer; the cooler and more acidic the mash, the sweeter and thicker[4].
All grains are combined in the tun and added to brewing liquor at a temperature higher than the final mash temperature to compensation for the cooler grains. This temperature is known as the strike temperature and is typically around 72°C. In commercial breweries the grain is heated so as to reduce the need for a higher strike temperature. The grains are then allowed to steep in the water at a temperature as close as possible to 66°C for around 90 minutes.
The wort is then removed to a boiler via a tap and the grains washed with hotter water to obtain all the sugars and stop any further enzymatic reaction in a process known as sparging. Temperatures suggested for this range from 70°C[5] to 77°C[6]; a common compromise is around 75°C.
The wort is then boiled for around 90 minutes. Copper hops are added at the beginning of the boil and flavouring hops after 75 minutes. Irish Moss, a form of seaweed, is typically added at the beginning of the boil to help prevent any hazes in the final brew. Haze-preventing additives to the boil are known as copper finings.
[edit] Fermentation
The wort is prepared for fermentation by cooling it down to pitching temperature; (70-75 °F or 21-24 °C- but if it is possible, 18C-20C is best). Quick cooling and isolation from the ambient atmosphere is needed to prevent early bacterial contamination or oxidation of the wort. Often, cooling is hastened by the use of thermal heat exchangers, informally, wort chillers, which often consist of copper tubing immersed in the wort, through which cold water flows. For larger volumes of wort, a counter-flow wort chiller can be used, in which the hot wort flows through copper tubing which is jacketed by a second tube (often garden hose) through which cold water is run in the opposite direction from the wort's flow. A more primitive and less effective method is to immerse the pot in a sink full of ice water.
The cooled wort is poured into the primary fermenter in an aggressive manner, so as to aerate the wort; sufficient oxygen is vital for the yeast's growth stage. Advanced homebrewers may further oxygenate the wort by bubbling filtered air or even pure oxygen through the cooled wort. The yeast is then pitched (sprinkled or poured) into the wort. If a dried yeast is used, some brewers rehydrate it first to reduce 'lag time', or the time taken before the yeast starts working. Although more expensive than dry yeasts, a number of liquid yeasts are also available, offering a range of flavor characteristics that allow the brewer to more closely approximate various beer styles.
Primary fermentation takes place in a large glass or plastic carboys or food-grade plastic bucket, nearly always sealed, but traditionally can be left open. When sealed, the fermenter is stoppered with the carbon dioxide gas produced venting through a fermentation lock. During this time, temperatures should be kept at optimum temperature for the fermentation process. For ale this temperature is usually 65-75°F / 18-24°C, and for lager it is usually much colder, around 50°F / 10°C. A vigorous fermentation then takes place, usually starting within 12 hours and continuing over the next few days. During this stage the fermentable sugars (maltose, glucose, and sucrose) in the wort are consumed by the yeast, while ethanol and CO2 are produced as byproducts by the yeast. A layer of sediment, the trub, appears at the bottom of the fermenter, composed of heavy fats, proteins and inactive yeast. A sure sign that primary fermentation has finished is that the head of foam (krausen), built by bubbling of CO2, falls.
[edit] Conditioning
Often, the beer is then racked (siphoned) into another container, usually a carboy, for aging or secondary fermentation. Fermentation is actually complete, so the term secondary fermentation actually refers to conditioning. Racking is done to separate the batch from the afore-mentioned trub so that it is not used as food, as this can give the beer an off-flavor. Racking also helps separate the beer from sediment, making it less likely to find its way into the finished product. During secondary fermentation some chemical byproducts from the primary fermentation are digested, which considerably improves the taste. Secondary fermentation can take from 2 to 4 weeks, sometimes longer, depending on the type of beer. Additionally, lagers are aged at this point for at near freezing temperatures for 1-6 months depending on style. This cold aging serves to reduce sulfer compounds produced by the bottom-fermenting yeast and to produce a cleaner tasting final product with fewer esters. Some homebrewers will keep the batch in the primary fermenter, called single stage fermentation, for the entire process. The potential drawbacks include added sediment in the finished product and a greater risk of off flavors. The tradeoff is this eliminates the need for a second container, reduces labor, and reduces the likelihood of contaminating the batch with bacteria, or oxidizing it, during transfer to the second container. This is a good beginner strategy, especially for those not skilled with racking.
Once this secondary fermentation is finished, the beer is ready for carbonation. There are two methods of carbonation. The first method does not require much capital expenditure per batch but is more time consuming. About 3/4 cup of corn sugar (dextrose) or other fermentable sugar is added to the beer, which is then transferred to bottles and then capped, or placed in a keg. The fermentation of the priming sugar in the closed container by left-over yeast suspended in the beer creates carbon dioxide which then dissolves into the beer. This takes 1-2 weeks. The second method involves pressurizing carbon dioxide into the beer into a special type of keg - either a Cornelius keg, the kind used in restaurants for soda storage, or a pressure barrel. Canisters of carbon dioxide, or soda chargers, can be released into the pressure barrel directly. The carbonation process then occurs almost instantaneously.
Using the first carbonation method, sediment will remain at the base of the bottles after completion. At this point it is referred to as the dregs, and an experienced homebrewer learns how to decant the beer, with minimal contribution to the taste of the beer in the mug. Some wheat beers, however, demand the sediment be rotated through the beer before it is served.
When using natural carbonation, the fermentation process restarts, although in a much smaller scale. The yeast must ferment the sugar, then clean up the byproducts of fermentation as in the secondary phase. Because the yeast population is much smaller, the process can take up to and beyond two weeks beyond full carbonation. Once the bottle/keg conditioning phase ends, the beer begins aging. Aging typically rounds out any rough edges in the beer and can remedy many imperfections. Some beers such as wheat beers are considered best with little to no aging, while bigger, higher alcohol beers can benefit from age for years.
During all stages attention to sanitation is essential. All items that come in contact with the wort or brew, must be soaked in a sanitizing solution and thoroughly rinsed, or immersed in boiling water.
When using malt extract, additional steps can be taken to add different flavors. Specialty grains are malted grains that do not require mashing. They are commonly steeped to add flavor, body and color at the beginning of brews. Sometimes hops are added at later stages for aroma and flavor, or dry hopped, (added just after secondary fermentation). Malto-dextrin, oak chips, and numerous other flavoring can also be experimented with.
There are several instruction books available. Some are more detailed than others, but homebrewing can be as simple or as complicated as you want it to be. The basic process does not require a great deal of technical knowledge, and the results are very much under the control of the brewer.
[edit] See Also
[edit] References
- ^ Wheeler Home Brewing: The CAMRA Guide 1993 p69
- ^ Muntons plc homebrew range - Commercial site. Retrieved on October 17, 2006.
- ^ Ibid. Retrieved on October 17, 2006.
- ^ Wheeler Home Brewing: The CAMRA Guide 1993 pp76-77
- ^ Line Brewing Beers Like Those You Buy 1978 p37
- ^ Wheeler Home Brewing: The CAMRA Guide 1993 p83
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