Eur Food Res Technol DOI 10.1007/s00217-015-2542-7 ORIGINAL PAPER Comparison of fermentation results and quality of the agricultural distillates obtained by application of commercial amylolytic preparations and cereal malts Maria Balcerek1 · Katarzyna Pielech‑Przybylska1 · Ewelina Stra˛k1 · Piotr Patelski1 · Urszula Dziekon´ska1 Received: 8 June 2015 / Revised: 26 August 2015 / Accepted: 30 August 2015 © The Author(s) 2015. This article is published with open access at Springerlink.com Abstract The objective of this study was to determine lower concentrations of undesirable acetaldehyde than the the efficiency of rye starch hydrolysis in mashing pro- distillate obtained from unmalted rye alone. cesses using either enzymatic preparations or cereal malts and their effect on the chemical composition of prepared Keywords Starch · Hydrolysis · Cereal malt · Rye · mashes, fermentation results, as well as the composition Agricultural distillate of the obtained distillates. The raw materials used were unmalted rye grain and different malts (wheat, rye, and barley malts). The differences in the chemical composi- Introduction tion of the distillery mashes, depending on the type and amount of malts used, were observed. The concentrations Cereals are extensively used to produce alcoholic bever- of reducing sugars were twice as high in mashes contain- ages, such as beer, vodka, whisk(e)y, bourbon, and others. ing 30 % cereal malts as in the reference sample prepared Alcoholic beverages made from fermented grain mashes 1 with enzymatic preparations (56.2 1.8) g glucose L− are widespread and highly respected around the world for ± mash. An increase in the content of cereal malt in mashes their flavor and taste. The most frequently consumed alco- from 30 to 50 % did not significantly improve the initial holic beverage in the world is beer [1]. The use of cereals degree of starch saccharification. The highest ethanol con- as raw materials by the brewing industry can be divided tent (8.40 0.25) % vol. was found in the mash containing into two main categories: malt and adjuncts. Also, many ± 50 % rye malt, but the fermentation efficiency in this case distilled beverages are produced from malt because of fla- was the lowest among all fermentation trials and reached vor enhancement [2]. only (75.39 1.88) % of the theoretical value. The high- Barley (Hordeum vulgare, vulgare L.) is the primary ± est efficiency of process (87.92 2.19) %, comparable to cereal used in the production of malt in the world. Two ± that obtained from the rye mash digested with amylolytic types of barley are frequently used for the malting pro- preparations (86.60 2.17) %, was found in the mash pre- cess: 2-row and 6-row. Two-row barley produces malt with ± pared with 50 % wheat malt. The fermentation of mash a large extract, lighter color, and less enzyme content than containing 50 % unmalted rye grain and 50 % barley malt the 6-row type [3]. gave the lowest ethanol concentration (6.60 0.12) % vol. In many countries, the production of barley malt-based ± in the mash after fermentation. The distillates originating spirits, such as Scotch whisky and Irish whisky, has a from mashes containing cereal malts were characterized by centuries-old tradition and constitutes an important sector of the economy. Generally, they differ in terms of the type * Maria Balcerek and proportion of the cereals used as raw materials and in [email protected] terms of the type of stills used in the distillation process. The principal types of whisky also differ by geographical 1 Department of Spirit and Yeast Technology, Institute region. A characteristic feature of Scotch malt whisky is of Fermentation Technology and Microbiology, Lodz University of Technology, Wolczanska 171/173, that the only cereal used in its manufacture is malted bar- 90‑924 Lodz, Poland ley. It is the most commonly malted grain, in part because 1 3 Eur Food Res Technol of its high diastatic power, or enzyme content, though which leaves more of the cereal taste in the finished spirit. wheat and rye are also used [4, 5]. In the production of Traditional Korn contains at least 32 % of alcohol by vol- Scotch whisky, malted barley is used as a source of both α- ume (ABV), while Doppelkorn or Edelkorn must contain at and β-amylase. After milling, the grist is mashed in a tun. least 37.5 % ABV [19]. During mashing, the enzymes present in the cereal malt Rye (Secale cereale) has been cultivated in Europe since catalyze the hydrolysis of starch into fermentable sugars ancient times and is genetically related to wheat and barley. (especially maltose) [6, 7]. The production of malt whisky Representing <1 % of the world cereal production, rye is shares many parallels to the production of an all-malt beer. mainly grown where rye breads are most popular, i.e., in The fundamental difference between distilling and brew- countries such as Poland, Germany, and Western Russia. ing production practices is that Scotch whisky distillers do The rye grain is second after wheat in importance for the not boil their worts, since they need to retain the maximum production of breads, and it is also important in the distilla- levels of endogenous enzyme activity into the fermentation tion of rye whisky and as livestock feeds [20]. process to ensure that as much of the starch as possible is Poland and Lithuania have a tradition of making Starka hydrolyzed to fermentable sugars, which can be converted from aged raw rye spirits, which dates back to the late six- efficiently into alcohol by yeast [8]. teenth and early seventeenth centuries. The basic raw mate- In the manufacture of Scotch grain whisky, other cereals rial in the production of Starka is rye distillate (raw spirit) are used along with malted barley to supply additional starch of suitable organoleptic properties and alcoholic strength in the mash tun [5, 9]. For many years, maize was the tradi- by volume (ASV) of 91–92 %. A meaningful element of tional grain for Scotch grain whisky production, until it was the assessment of the usefulness of a rye distillate for the effectively replaced by wheat, primarily because of its more production of this spirit is the determination of higher alco- favorable economics [10, 11]. Assessment of wheat varieties hols, whose desirable content is estimated at approximately 1 by the distilling industry and dialogue with plant breeders 2 g L− 100 % vol. alcohol, but raw spirits with their con- 1 has led to obtain improved varieties from which distillers are tent of 3–3.5 g L− 100 % vol. alcohol also often provide capable to produce alcohol with yields equivalent to those good results. In fact, the results depend on the relative obtainable from maize [12, 13]. Despite the fact that wheat proportions of the various alcohols, i.e., n-propyl, isobu- has successfully replaced maize, there are still some con- tyl, isoamyl, and other alcohols, which often occur in very cerns regarding difficulties with handling this cereal in the small amounts, but nevertheless influence the organoleptic distillery. These result from the higher viscosity, associated properties of matured distillate [21]. with wheat, which can affect the efficient handling of stream Due to the importance of the spirits industry for con- process (cooking and mashing). Therefore, maize is still con- sumers, producers, and the agricultural sector [22], tech- sidered to be superior to wheat as it produces higher alcohol nological innovation should be applied both to improve the yields and presents fewer processing problems. quality of traditional spirits and to create new original spirit Cereals such as sorghum and millet are considered to drinks. Also taking into account that there is an increase in have similar characteristics to maize and can be consid- amount of micro-distilleries worldwide, which gave better ered to use in the brewing process [14]. Sorghum is used as care and attention to craft or niche products [23], the pro- malted and distilled beverages in Africa and Asia [15, 16]. duction of spirits from malted and unmalted cereals may be Europe’s spirit drinks industry is the largest in the world. incorporated in the manufacturing portfolio of small distill- The main raw materials used by the EU spirit drinks indus- eries to bolster their competitiveness and facilitate attract- try are the agricultural products (cereals, potatoes, sug- ing new customers interested in nonstandard distillates. arcane, sugar beets, and wine) used to make the different The development of production technology of new kinds kinds of spirits, and 85 % of them is based on grain [17]. of distillates contributes to expanding the range of products Value of production of agricultural products, among and increases the production capacity of Polish distilleries. other spirits, is protected by a geographical indication The objective of this study was to determine the effi- (GI). Scotch whisky, Korn, and Polish Vodka are exam- ciency of rye starch hydrolysis in mashing processes using ples of EU geographical indications with an international either enzymatic preparations or cereal malts as a source of reputation linked to the geographical area where they are amylolytic enzymes and starch and their effect on the phys- produced [18]. Korn or Kornbrand is one of the interesting icochemical composition of the prepared mashes, fermenta- grain spirits produced in Germany, Austria, and Belgium tion results, and the composition of the obtained distillates. (German-speaking community) [18]. According to the Ger- The scope of this study included: man Purity Law of 1909, Korn may only be produced using whole grain rye, wheat, barley, buckwheat, or oat, grown on • physicochemical analysis of raw materials; German-speaking land. Korn differs from vodka as it is dis- • preparation of sweet mashes by pressureless liberation tilled to lower alcoholic proofs and less rigorously filtered, of starch (PLS); 1 3 Eur Food Res Technol • establishing the impact of the source of amylolytic was adjusted from 5.5 (during mashing) to 4.5 using sul- 1 enzymes (enzymatic preparations or cereal malts) on furic acid solution (250 g kg− ).