Grains provide flavor, body, color and texture to the beer. The most common malted cereal used in the brewing process is barley. Other malted cereals can also be used such as wheat to brew wheat beers. The malting process triggers enzyme production which will in turn break down the starch into fermentable sugars. The process of malting is halted by kilning the malt when the grains reach an optimal concentration of sugars (saccharification) and enzymes.

The length of time and temperature of kilning will determine the color and aromas of the malt. A highly saccharified malt dried at high temperature will induce a reaction between the sugars and amino-acid resulting in a caramel malt sweet and dark. A malt with low breakdown of starch, dried at high temperature will be colored without the sweetness. This roasted malt is used for stouts and porters when sweetness in the beer is not desirable. Malt dried at low temperature will remain pale and be ideal to brew a lager.

The concentration of malt in the mash will dictate the final alcohol concentration of the beer. The original gravity (OG) is the specific gravity before fermentation and the final gravity (FG) is measured after fermentation when the sugars have been transformed into alcohol. Some unfermentable sugars will remain and contribute to the body and sweetness of the beer. The alcohol content can be calculated by subtracting the OG-FG and dividing by 0.00738.

Hops...

Hops were introduced in beer-making during the 16th century. The flowers of the female plant contain a substance called lupulin. The acids in the lupulin give bitterness to the beer and the hop aromas come from the essential oils. Hop acids are also antiseptic against certain types of bacteria. Hops are added during the boiling process in order to convert the acids into bitter compounds. Some more aromatic hops can also be added at the end of the boiling process to release the aromas which would otherwise be removed by steam during boiling. Dry hopping consists of adding hops during maturation to release a fresh aroma and flavors; these are usually described using the following terms: grassy, floral, citrus, spicy, piney and earthy. Hops are available in flowers, pellets or extract.

Bitterness is expressed in IBU's (International Bittering Units). 100 is the maximum on that scale although some beers on the market advertise higher levels. The perception of the bitterness is affected by the concentration of malt. For example, the same level of IBU in a stout will be less noticeable than in a pale ale.

Lagers are usually brewed with Czech or German noble hop varieties such as Saaz, Hallertau, Tettnanger and Strissel Spalt which are aromatic. The British use hop varieties such as Northern Brewer (bittering + aroma), Fuggle (bittering + aroma), Golding (aroma) and Bullion (bittering) for their beers. North American Brewers use mainly Cascade, Chinook, Centennial, Willamette and Amarillo hops; which release bitterness and aromas.

Yeast...

A yeast culture is composed of microscopic unicellular organisms round or oval of 10-15 microns. The yeast cells feed on the sugars of the wort and produce alcohol, biomass and CO2 as a result. The brewing yeast called Saccharomyces cerevisiae produce ale beers whereas Saccharomyces pastorianus produce lager beers. Both types of yeast are genetically different and lager yeasts prefer to ferment at lower temperature and flocculate to the bottom of the fermenter. Ale yeasts favor higher temperature and flocculate to the top.

In addition to producing alcohol, the yeast also generates many other chemicals which impact the final flavor and aroma of the beer. Ale strains are very varied and tend to produce fruity beers due the excretion of a variety of esters. Lager strains are much less diverse and tend to produce 'clean' beers for which the impact of the yeast is not as noticeable.

Brewing yeasts are available in liquid form or in dry form; the pitching rate for brewer's yeast will depend on the original gravity of the wort to be inoculated. As a rule of thumb, 1 million viable cells per ml of propagated or recycled yeast are inoculated per Plato degree (to convert gravity in Plato degrees, divide the last 2 decimals by 4, 1.040=10°P. Liquid and dry yeast manufacturers may have their own recommendation according to their particular product. For more information on yeast please have a look at the Lallemand' sponsored yeast section of www.ProBrewer.com/resources/yeast 

Water...

The principal ingredient of the beer is water accounting for 95% of the content for a standard beer. Water is used for malting, cleaning, brewing and cooling; 5-6L of water is needed to brew one liter of beer. Hardness refers to the amount of calcium and magnesium ions in the water. Some beers are brewed with soft water such as European lagers and pilsners. Other beers are famous for being brewed with hard water, the best example being the pale ales from Burton-on-Trent in England. The word 'burtonization' is commonly used in brewing and means adding calcium sulfate to the water to mimic the brewing conditions of the famous English city.

The mineral salts in the water are particularly important for the body and character of the beer. Mineral salts can either be added or removed to maintain consistency especially if the same brand of beer is brewed in different regions of the world.

The level of carbonates is probably the most important factor since it influences the efficiency of a-amylases. A high pH does not encourage the conversion of starch into simple sugars; an ideal pH for mashing is between 5.2 to 5.5. Sodium contributes to the body and character of the beer. Chlorides help bring out the soft mild flavor of the malt and also add complexity to the beer. Sulfates have a direct impact on hop dosage. Too much sulfates increase the bitterness of the hops so they both need to be balanced to achieve the required bitterness. Calcium encourages the precipitation of proteins during fermentation and is important for yeast flocculation. It also helps with some enzymatic reactions including those involving a-amylases. Magnesium and Zinc levels also will play a role on the activity of the yeast.