Bijay Bahadur, Factory Manager, YBL (Sikkim)
Beside the major brewing raw materials barley and barley malt, various starch sources like maize (corn), rice, wheat, sorghum, rye and cassava, as well as syrups and sucrose from both sugar cane and sugar beet, are widely used in the brewing industry. Price and availability of the raw materials are greatly influenced by an increasing demand due to the growing population and beer consumption worldwide.
Various crops like barley, rice, wheat, maize and sorghum are mostly limited to specific countries or small regions. The cost pressure has led breweries across the globe to look for alternative brewing materials. Availability, cost and grade, as well as brewer and consumer expectations have always influenced the selection of the brewing raw materials. However, increasing cost pressure has led to further constrained adjustments in beer recipes over the last couple of years, with more focus on cost effective and sustainable alternatives. The Brewery is also challenged by seasonal and regional availability, fluctuation in price and quality caused by climatic conditions during cultivation and harvest. As a consequence, there is generally a need for stronger strategic focus on raw materials sourcing.
Exogenous enzymes have regularly been established to balance processability, increase yield and assure wort and beer specifications. Broadly speaking, even higher flexibility in the raw material sourcing is desirable to compensate for variability as well as fluctuations in the raw materials market and its quality.
Enzymes plays a vital role to work in synergy with the existing enzyme systems in the various grains (barley, barley malt, broken rice etc.) to enable the degradation and utilization of cereals beyond the traditional malt-based enzyme configuration. To ensure optimal processability and fermentability, different enzymes containing glucanases, xylanases, proteases, amylases, pullulanases (limit dextrinase) and lipase activities are optimally combined according to the properties of the relevant raw materials.
Guide for Raw Material Optimization
Table 1.0 shows an overview of recipe opportunities and accordingly select right enzyme with recommended dose to reach standard processability and fermentability. The focus of the enzyme application is to support the cytolytic, amylolytic and proteolytic degradation within an efficient mashing process and without compromising yield.
Table 1.0 Examples of potential recipes in % extract
Opportunities for Individual Raw Material Optimization
For recipes containing 100% malt or small replacements by barley up to 20%, the main focus of the enzyme application is on the cyctolytic degradation of cell wall components like β-glucans and arabinoxylans to improve lautering performance and beer filtration also on well-modified malt and to increase the extract yield.
Processing high gelatinizing adjuncts like rice in a cereal cooker with an enzyme which provides a fast and effective viscosity break and forms the basis for effective starch saccharification.
Rice is currently the second most-widely used adjunct material. On an extract basis, it is approximately 25% more expensive than corn grits. Brewer’s rice is a by-product of the edible rice-milling industry. Rice is preferred by some brewers because of its lower oil content compared to corn grits. Rice has a very neutral aroma and flavor, and when converted properly in the brewhouse, yields a light, clean-tasting beer.
The quality of brewer’s rice can be judged by several factors, including cleanliness, gelatinization temperature, mash viscosity, mash aroma, moisture, oil, and ash and protein content. Rice should be free of seeds and extraneous matter. Insect or mold damage should not be tolerated, as these indicate improper storage or handling conditions. It has been reported that rancidity in rice oil can be a problem, but with modern storage techniques this is a negligible factor.
Not all varieties of rice are acceptable brewing varieties. Rice has a relatively high gelatinization temperature and is extremely viscous prior to liquefaction in the cereal cooker. Rice liquefies more easily the finer the particle grind, and particles less than 2 mm are considered adequate. Handling of rice is relatively easy, as the broken contain little dust and flow easily through standard hopper bottoms and conveying equipment. Rice is milled in fixed roller mills. There is no difficulty in making the rice mash slurry at 64 to 76 ͦC, although it is a common practice to mash and hold at 36 to 42 ͦC as a protein rest. As with all cereal cooker operations, whatever the starch source, 5 to 10% of the malt grist is added to the cooker because the malt enzymes (amylases and proteinases) are essential for the partial liquefaction necessary to render the cooker mash fluid enough for pumping. Atmospheric boiling is required for gelatinization.
If properly converted, rice adjunct usage does not create runoff problems as the extract is slightly lower in soluble nitrogen than corn grits.
Wheat malt is used in the production of some special types of beer, in which it may constitute 75% of the grist, but only to a limited extent in ordinary beers. The limited use of wheat malt is mainly due to the difficulty experienced in malting the naked grain without damage to the exposed acrospires. As a result, much of the wheat malt made has been under modified. However, the absence of the husk tends to result in a high extract. Wheat malt gives beer outstandingly good head retention.
Malt based recipes with high levels of alternative raw materials and adjuncts
Utilizing high amounts of under modified malt, or malt in combination with high portions of barley, rice or maize (corn) can impact sufficient FAN supply for the yeast as well as lead to limited diastatic power during mashing. This would lead to extract losses and poor fermentability.
Barley based recipes
Unmalted barley is an adjunct for use in brewing. However, the raw grain is abrasive and difficult to mill, scattering to yield too high % of fine material which gives problems during lautering. These difficulties disappear if the grain is conditioned to 18 to 20% moisture prior to milling although this process has not been widely employed in brewing.
Use of barley leads to a reduction in wort nitrogen content and decreased wort and beer color. Foam stability is usually improved because of lower levels of proteolysis. However, a major difficulty associated with brewing with high levels of unmalted barley can be the increase in wort viscosity and runoff times caused by the incomplete degradation of b-glucans. Hence, it is suggested to pre-treatment of the barley with b-glucanase and the use of a temperature-stable b-glucanase in the mash.
Raw (feed) barley can also be employed as an adjunct, and as high as 50% barley in the grist Use of raw barley requires significant modification to the brewing process. This high level of malt replacement usually results in insufficient malt enzymes for the necessary hydrolysis of the starch, protein, and b-glucans. Consequently, a malt replacement enzyme system is employed to compensate for the reduced level of malt enzymes.
In barley brewing, it is possible to approximate the starch hydrolysis profile and the degree of fermentability of 100% malt worts. This is possible by substituting malt with barley at levels of 50% (extract basis) and by controlling the main mash schedule (enzyme concentration, time, and temperature). Barley worts have been found to contain less fructose, sucrose, glucose, and maltotriose but more maltose than malt worts. In general, no significant difference in organoleptic properties between barley beers and 100% malt beers have been observed. A harshness of barley beers can be avoided by lowering the pH of the wort to 4.9 prior to boiling.
Using the full potential of exogenous enzymes, the brewer can create recipes with up to 100% barley. Enzyme activity provided by pullulanase that hydrolyzes (1,6)-alpha-D-glucosidic linkages in pullulan, amylopectin and glycogen enables brewers to brew maltose-based wort with standard fermentability and similar processability compared to using high portions of malt. The present pullulanase, amylase and protease activities ensure sufficient starch and protein degradation in synergy with the β-amylase and peptidases of the barley. The glucanase and xylanase components enable sufficient cell wall degradation and low viscosity. The lipase activity significantly improves the turbidity during lautering.
Using only barley and the enzyme, the brewer can produce a great-tasting beer while maximizing savings in raw material costs, gaining improved productivity, creating new beverages, and reducing the carbon footprint – all in just one simple process.
Background to application
To seize the cost saving opportunities that come with alternative raw materials and adjuncts in brewing, to drive sustainability in terms of local raw material sourcing, to create specific beer properties by using individual raw materials characteristics, or to level out inconsistencies in the raw material quality (including malt), the traditional enzyme source, malt, and the process that is based on it, can be the limiting factor. Either the enzymes are not sufficient in terms of temperature or pH characteristics, or the amount and function do not support the set-up of a modern raw material agenda.
The use of unmalted carbohydrates or adjuncts in brewing is widespread and these are usually the cheapest suitable carbon source. The brewing industry employs a wide range of cereals and sugars that have been processed by a number of methods. Although developments in the use of brewing adjuncts have been relatively stable for a number of years, the advent of “new-generation” syrups are currently having a great impact on the brewing industry. At the present time, syrups are available that allow the brewer to introduce at any level without changing the carbohydrate profile of the wort. The future will see the commercial ability to separate and isolate individual sugars according to their molecular weight and, subsequently, produce a blended syrup of any sugar profile.