# Maize and Sorghum as Raw Materials for Brewing, a Review
## 1 Introduction Cross-Reference  
Brewing is a food process that began in the Middle East 10,000 years ago [1]. Today, at almost 200 billion litters a year, beer is one of the most commonly consumed low-alcohol beverages in the world--and, in terms of volume, after water and tea, the third most prevalent beverage in general [2; 3; 4; 5; 6]. The largest manufacturer of beer in the world is China, followed by the USA and Brazil. In Europe, Germany has the highest rates of beer consumption and production [7]. Dating back to antiquity, people have exploited the grains in their vicinity to develop fermented drinks [8]. Over the past hundred years, advancements in brewing have led manufacturers to use other types of cereals, in addition to barley malt or wheat malt. In any industry, innovation is the key to remaining competitive, and the beer industry is no exception. Consumers are always searching for new products on the marketplace--a novel brand, an original taste, eye-catching packaging, innovative technology, health benefits, quality improvements, etc. [9; 10; 11]. Barley is the most used cereal for brewing: however, unconventional malted grains have been used successfully. For instance: rice is used in Asia, maize is used in America, and millet and sorghum are used in Africa [12; 13; 14]. This process of replacing barley malt in beer production is increasing, and several factors shown in Figure 1 have contributed to this. Because barley is used in such large quantities by all brewers, no matter their size, manufacturers often adopt various cost-cutting strategies. These can include the partial replacement of barley malt with adjuvants, considered supplementary sources of carbohydrates. The first adjuvants used in brewing were used to reduce the costs of obtaining the finished product [15]. For this reason, local raw materials--which may be available at lower costs and in higher quantities--can be used, provided they are in compliance with applicable legislation. Barley and maize are the most commonly used adjuvants in Europe as partial substitutes for malt [15; 16; 17]. Adjuvants are widely used in the beer industry (in variable proportions ranging from 10-50%) to provide additional sources of fermentable yeast carbohydrates, to improve foam stability, to change the color of beer, or to adjust the flavor of the finished product [18]. The literature states that 85-90% of world beer production is now produced with adjuvants, with wide variations on different continents. Between 10% and 30% of malt is substituted by unmallated materials in European countries; 40-50% or more is substituted in the United States and Australia, and in Africa the substitution is between 50 and 75% [17]. Beer adjuvants are ingredients--not including malted barley--that bring supplementary sources of protein and carbohydrates into the word. Various cereals--e.g., wheat, barley, sorghum, corn, rice, and oats--are frequently used in various forms (whole grains, semolina, flakes, boiled, extruded, roasted/micronized, flour/starch, syrup, etc.) to obtain different beers [19]. For example, the use of maize as an adjuvant in the manufacture of a 30% beer assortment has led to an 8% reduction in total production costs [20]. In the Netherlands, Belgium, Luxembourg, and France, the production of beer with up to 40% unmalled cereals is permitted by law and has been put into practice. Contrastingly, beer production using higher concentrations of adjuvants (>40%) is often prohibited or impracticable. Replacing barley malt with adjuvants in beer manufacturing can potentially reduce the total cost of raw materials and obtain a distinctive beer taste or aroma [21]. Currently, the most common adjuvant of beer is rice, but as the demand for this cereal has risen severely, the quest for more adjuvants to substitute rice is ongoing [22]. Some adjuvants could feature compounds that may have beneficial effects on people's health--e.g., vitamins, minerals, and phenolic compounds such as phytoestrogens [23].