Africa Goes Sorghum: Challenges and Opportunities
Total Page:16
File Type:pdf, Size:1020Kb
AFRICA GOES SORGHUM: CHALLENGES AND OPPORTUNITIES Moses Musisi w Nile Breweries Ltd, PO Box 762, Jinja, Uganda ABSTRACT Close Bar w Sorghum was first domesticated in Africa and has therefore played an important role in the culture and economies of African Countries since time immemorial. There are a number of key advantages and opportunities for brewing with sorghum including availability, knowledge of the crop as it is an indigenous crop, low price per kilogram of extract, gluten free and good colloidal stability of clear sorghum beer. Key brewing challenges include low free amino nitrogen (FAN) in sorghum worts that pause serious fermentation challenges, high tannin levels that bind proteins and therefore reduce enzyme efficiency, low foam potential, lack of a husk and low β-amylase even when sorghum is malted. Key research opportunities are there in areas of improving breakdown of kafirin to increase FAN, increasing foam potential, developing varieties with low tannin levels while at the same time resistant to birds, ability to brew with high tannin sorghums and production of other forms of brewing raw materials from sorghum like maltose syrup and starch. Africa grew clear beer volumes on average of 7% between 2005 and 2007 compared to 12% of SABMiller Africa between 2008 and 2010. ACKNOWLEDGMENTS I would like to express my thanks to Nile Breweries Ltd, a subsidiary of SABMiller, for having been kind to me to allow me to use the valuable resources that necessitated me to write this w paper. BACKGROUND Close Bar w Clear beer brewing has traditionally been from barley malt as a principle source of extract world over and other sources of raw materials only used as adjuncts. Adjuncts have been used essentially to supplement on malt for various reasons ranging from taste to cost. Sorghum has been used for brewing beer in Africa for ages, mainly for producing opaque beer, whose volumes still dwarf clear beer in many parts of sub-saharan Africa (SABMiller plc, 2009). Brewing clear lager beer from sorghum was put on industrial platform by Nigeria in the 1980s after government legislation banning importation of barley malt. In 2002, SABMiller in Uganda launched its first commercial brew made from raw sorghum and from that time brewing clear beer from sorghum has not scaled down but gone significantly up in various African countries in which it operates. Table 1: Projected clear beer production in Africa (After Canadean, 2008; SABMiller plc, 2009). Year 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 SABMiller Sorghum Beer 341 682 787 758 828 954 1,097 1,262 1,451 1,669 1,919 Nigeria Clear Sorghum Beer 8,269 9,468 10,412 11,453 12,599 13,858 15,244 16,769 18,445 20,290 22,319 w Total Africa Sorghum 10,615 12,156 13,206 14,219 15,436 16,822 18,352 20,042 21,909 23,973 26,253 Total Clear Beer Africa 71,923 76,969 82,653 88,439 94,629 101,253 108,341 115,925 124,040 132,723 142,013 Close Bar % Sorghum to Barley malt beer 15% 16% 16% 16% 16% 17% 17% 17% 18% 18% 18% w Key Opportunities from Sorghum 1. Sorghum is indigenous from Africa. Sorghum also called by its scientific name of Sorghum bicolor is a grass that has its centre of origin in Africa (FAO, 1995a). Its success in conquering marginal areas of land where there is little rainfall is because of its extensive w root system, its ability to thrive with less water than maize, which may be due to its ability to hold water in its foliage better than maize, its waxy coating on its leaves and stems which helps to keep water in the plant even in intense heat and its yields are not affected by short periods of drought as severely as other crops such as maize because it develops Close Bar its seed heads over longer periods of time therefore short periods of water stress do not w usually have the ability to prevent kernel development (New World Encyclopedia, 2009). It is a perennial grass, though it is treated as an annual crop and can be harvested many times during the year (FAO, 1995a). All those factors make sorghum have a competitive advantage over other cereals as a number one choice for brewers as a reliable source of extract. 2. Over 30% of world’s Sorghum production is from Africa. World annual sorghum production is over 60 million tonnes, of which Africa produces over 20 million tonnes (Taylor, n.d.). The high tonnage of sorghum produced from Africa means it is a raw material that is readily available in the region, which gives the brewing industry an opportunity to tap into the vast resource without excessive amount of investment necessary compared to a pioneer crop. 3. Sorghum beer tradition. Sorghum has been used to brew local beer in Africa for ages, so the taste and sound of a clear beer from sorghum is not foreign to the population. This shows that opaque beer volumes are three times bigger than clear beer in those selected countries in Southern Africa w Table 2: Sorghum production in Africa in 2008 (After FAOSTAT, 2010). Rank Country Production MT Close Bar 1 Nigeria 9,318,000 w 2 Sudan 3,869,000 3 Ethiopia PDR 2,316,041 4 Burkina Faso 1,875,046 5 Niger 1,311,100 6 Mali 1,027,202 7 United Republic of Tanzania 900,000 F 8 Egypt 866,948 9 Chad 685,430 10 Cameroon 600,000 F 11 Uganda 477,000 12 South Africa 373,000 * 13 Ghana 330,950 14 Eritrea 302,515 F 15 Rwanda 227,927 * w 16 Togo 210,298 * 17 Mozambique 204,986 * 18 Senegal 189,787 * Close Bar Total 25,085,230 w *: Unofficial estimate F: FAO estimate Table 3: Clear beer volumes compared to Opaque Sorghum beer in a few selected countries (After SABMiller, 2009). Country Clear Beer. '000 hl Opaque Sorghum beer. '000 hl Malawi 250 1000 w Zambia 520 1600 Close Bar Botswana 500 1500 w Zimbabwe 1000 2500 Total 2270 6600 4. Sorghum is gluten free. Beer made from sorghum can be taken by people who suffer from celiac disease. Gluten occurs naturally in barley, wheat, and rye (Wikihow, 2010) but is not present in Sorghum. While sorghum has been successfully used to replace malted barley in African countries such as Nigeria and Uganda, more recent interest in the area of gluten-free beer, has highlighted sorghum on the world-stage as a leading contender for the production of gluten-free beers (Kerry, n.d.). Anheuser-Busch is already marketing its gluten free beer Redbridge from sorghum syrup (Anheuser-Busch, 2010). Celiac disease affects 1% of the population (Marian et al., 2004). 5. Price of sorghum is low. Compared to other raw materials that are used to make beer, the w price of sorghum is low even on extract basis. Comparatively a kilogram of extract from barley malt is US$ 1.30 while that of sorghum is US$ 0.50 in Uganda for example. 6. Technological challenges are not insurmountable. The sorghum structure is very similar to that of maize except for its much smaller size and generally oval shape (Taylor, n.d.). For Close Bar example neither grain has a true hull (husk), unlike barley or rice. The absence of the husk w in sorghum grain was up until recently considered a major problem with regard to using sorghum on lauter tuns. The advent of mash filters has broken this technological barrier. Modern mash filters have comparatively good extract recovery. 7. Diversification into secondary products. Sorghum can still be used to produce syrups, powder or even pure starch. These can be used as raw materials in the brewhouse. Sorghum syrups can effectively be used to increase brewhouse capacity. 8. Sorghum has low fat compared to maize. While sorghum has a close structure similar to maize, it has much less fat content compared to maize, this therefore lowers the rancid potential of beer (Taylor, n.d.). Maize can only be used if it is further processed into grits where the germ has been removed or if it is further processed into pure starch. 9. Sorghum beer has very good colloidal stability. Compared to malt or wheat beers, sorghum clear beer has better colloidal stability (Armad et al., 1998). This is due to polyphenolic compounds that have beneficial “functional” anti-oxidant properties. Brewing experience at SABMiller shows that beers made out of sorghum not only have longer shelf lives based on colloidal stability but also organoleptically. w Key Challenges of the Sorghum Industry 1. Decision to brew with malted sorghum or raw sorghum is a challenge as each has its cons Close Bar and pros. w 2. Brewing challenges: a. One of the major challenges of brewing with raw sorghum is that of very low free amino nitrogen (FAN) (Chisala et al., 2008). Several studies have shown that the levels of FAN in sorghum grain wort mashed with commercial enzymes are considerably lower than those obtained with sorghum and barley malt. The low levels of FAN attained when using exogenous proteolytic enzymes can be attributed primarily to the factors that contribute to the low digestibility of the kafirin fraction of sorghum protein, which accounts for around 70% of total grain protein. Use of reducing agents like 2-mercaptoethanol, sodium bisulphate and ascorbic acid, improve sorghum protein hydrolysis (Chisala et al., 2008). Low FAN leads to tailing fermentations and therefore low fermentation efficiency. b. Tannin levels in sorghum pause a challenge in that it binds with both the grain proteins w (Price et al., 1980) and the exogenous enzymes.