BASICS OF SPIRITS PRODUCTION ● have broken this trend. Annual produc- tion output from production facilities processing both un-malted and malted Grain spirits barley, or commercial enzymes is well in excess of this 10Mla, with some hav- ing capability to produce more than ten production times this volume. This is the type of process employed to produce Scotch grain whisky, grain Milling and mashing neutral alcohol and the signifi cantly larger-scale operations of the fuel alcohol industry. Starch in its natural en- vironment is an energy source stored in the endosperm of the cereal grain and is generally bound, to varying extents, with proteins in and around the endosperm. In its fi xed state it is insoluble in water and requires vigorous treatment to make it more readily available for conversion to fermentable sugars in the conversion or mashing processes. Accessing this fi xed starch is highly energy-intensive, and the two primary methods are by cooking with water istock.com/PytyCzech at high temperature and pressure, or By Billy Mitchell by physical/mechanical treatment by breaking down to very fi ne fl our by ham- mer milling. These will both be explored In this, the third article in the series to support those in more detail later in this article. studying for the General Certifi cate in Distilling, we look Figure 1 gives a high-level sim- ple schematic overview of these at the plant and processes used in the production of spirits processes. As already stated, these from primarily non-malted raw materials. We will also look processes require signifi cant input of either thermal or physical energy in at some of the processes employed to hydrolyse starch in the form of either high-pressure steam non-malted grains and how that hydrolysed starch can be and/or electrical power. Accessing the starch also requires input of a signifi - converted into fermentable materials for conversion into cant volume of water. Combining the alcohol in the subsequent fermentation process. throughput of raw materials, water, thermal and electrical energy in these n these processes the starch source This is not an issue in the process- processes provides a great opportunity Ioriginates from non-malted cereals ing of 100% malted barley, as excess for energy recovery and reuse, and such as maize and wheat – and the enzymes are present in this mash bill. this is another key factor in delivering enzyme source originates from high- Use of insuffi cient malt or commercial effi cient production of product. enzyme malted barley or via a com- enzymes will result in loss of effi ciency mercial enzyme source. Specifi cations by failure to convert available starch, The biochemistry for these were discussed in the fi rst while use of excess enzyme will add In the article Raw Materials for Cereal article in this series, Raw Materials for unnecessary costs to production. Distilling I reviewed how amylase and Cereal Distilling (Brewer and Distiller amylopectin are the two forms of starch International, June 16). General principles that are produced by cereals and stored In the production of Scotch grain The ultimate goal of each spirits in the endosperm. I also discussed the whisky only endogenous enzymes from producer is to produce the maximum general composition of the main cere- malted barley are permitted, as defi ned volume of alcohol, of the required qual- als used in sprits production and gave in the Scotch Whisky Regulations. For ity, for each type of mash bill using the an overview of many of the raw material production of non-Scotch grain whisky, minimum volume of water, utilities and specifi cations employed. In this article exogenous enzymes are allowed. These energy. This is a fairly simple state- we will focus on the two main cereals can be used both in the starch hydrolysis ment of intent but delivery of that goal used in grain spirits production, namely and conversion processes and can totally in these processes can be challenging. wheat and maize. replace endogenous malt enzymes if re- One of the main reasons for this is due While the starch is provided by quired. One key element to be carefully to the scale of the operations involved. the wheat and/or maize, the enzyme considered if using malt or commercial The total annual output from an av- source can be provided through the enzymes, or a mixture of both, is to en- erage facility processing 100% malted inclusion of a relatively small portion sure the concentration of these enzymes barley, is generally considerably less of high-enzyme malted barley or by is such that effi cient conversion of starch than 10Mla (million litres of alcohol) per the use of commercial enzymes read- to fermentable materials is achieved. year, however, some newer facilities ily available to this industry. Endog- www.ibd.org.uk Brewer and Distiller International November 2016 z 31 l BASICS OF SPIRITS PRODUCTION – this term is used to describe the com- bined activity of these two enzymes. Grain storage General storage stock To fully understand these enzymatic actions on the amylose and amylopectin starch structures, you should firstly re- Grain cleaning Removal of debris acquaint yourself with these structures as outlined in Raw Materials for Cereal Distilling. An amylase is an enzyme that catalyses the hydrolysis of starch into Accurate weighing of raw Grain weighing sugars – let us now review the main two material amylases involved in this process. Beta-amylase Beta-amylase is an exo-enzyme, which Cooking process Low temperature process starts at one end of a chain of glucose molecules and works its way along the High enzyme malt Commercial enzyme chain splitting off two glucose units at a time. Two glucose units joined together form the structure of maltose and so beta-amylase will produce mainly malt- ose from a chain of linear glucose units, Mashing fermentable although some glucose and maltotriose sugar may also be liberated due to different chain lengths. Beta-amylase action ceases whenever a branching point is Batch or continuous Wort cooling reached on a non-linear glucose chain. process From this it can be assumed that the enzyme working alone on starch (amylose and amylopectin) Figure 1: Grain preparation and mashing will convert all the linear amylose enous enzymes must be used when reaction and no other. Because of this, primarily to maltose, although it will producing Scotch grain whisky while the breakdown of a complex organic only hydrolyse around 50% of the commercial enzymes with or without material frequently requires a group of branched amylopectin. In the case of endogenous enzymes will be used in enzymes working together, since each the latter, the ends of all the branches other spirits production. one will confine itself to only one part will be ‘pruned’ until a dividing point Enzymes are protein-like sub- of the material breakdown. is reached leaving a substance called stances associated with all living A similar situation arises in the beta-amylase limit-dextrin. material. They possess the property of breakdown of starch by malt enzymes. being able to rapidly carry out chemi- At least two enzymes are required to Alpha-amylase cal reactions under normal conditions deliver anything like a 100% conversion Alpha-amylase acts in a completely of temperature and acidity – reactions of starch to fermentable sugars and different manner. It is an endo-enzyme which would generally be impossible these are called alpha and beta-amyl- which makes random attacks on the in their absence except in an extreme ase. Historically before enzymes and starch molecules eventually producing environment of very high temperature their activity were fully researched and fragments of a length between six and or the extreme limits of pH. Enzymes understood, the action of malt enzymes twelve units from both amylose and are highly specific – one particular on starch was referred to as being amylopectin. If alpha-amylase were to enzyme will carry out its own specific brought about by the ‘diastase’ of malt act alone on whole starch, then for all When the malt has been Starch consists of a long This sugar is called mashed with water, enzymes chain of sugar(glucose) maltotriose. It will ferment are released which attack molecules linked together slowly the links in the starch chain at the points shown by There are some branches in This sugar is called arrows the chain maltose and ferments Alpha Amylase attacks at quickly random points in the chain. There is a high level of activity during mashing This sugar is a dextrin and it will not ferment Beta amylase attacks at Maltase has a very the second to last link in low level of activity the chain This sugar is called glucose and it ferments very quickly Enzyme action and structure of glucose, maltose and maltotriose 32 z Brewer and Distiller International November 2016 www.ibd.org.uk BASICS OF SPIRITS PRODUCTION l practical purposes the end result would be to produce a number of multi-unit glucose units i.e. dextrins, which would Grain storage not be fermented by yeast, and so the presence of both enzymes is essential. Since neither alpha or beta-amylase can break the branching points of amy- Grain cleaning lopectin these remain – and even the combined action of both enzymes leave a small percentage of starch in the form Grain weighing of un-fermentable limit-dextrins, other active limit-dextrinases will eventually break these down during fermentation. Rough milling or whole The main objective in mashing is Batch or continuous Grain preparation to convert the starch into fermentable grain sugar; other enzyme-driven protein breakdown reactions are also relevant for yeast nutrient, yeast growth and fla- Hot water Grain cooking Cooker discharge vour development during fermentation.