Enzymes and Their Functions
- Ethyl alcohol is an organic compound (C2H50H) which is also known as ethanol.
- The sugar extracted from cane or sweet sorghum can be directly fermented with little or no alteration,
- Starches present in grains must be converted into sugars.
- Starch itself is nothing more than a long chain of individual glucose molecules, which must be broken apart or hydrolyzed
- The conversion process must be very carefully carried out, or your final alcohol yield will be seriously reduced.
- The critters responsible for the transformation of starch to sugar and then sugar to alcohol are called enzymes, chemically
known as protein biocatalysts.
- Enzymes are products of living cells,
- they encourage a chemical change without being consumed during the process.
- There are thousands of enzymes, and each one performs a specific task at an optimum temperature and acidity level
- All enzyme names end in the suffix "ase", while the first portion of each of these terms describes the substance that
enzyme specializes in converting. (ie: cellulase converts cellulose into sugar.)
- All living cells produce enzymes, and grains are no exception.
- When a seed germinates, the enzymes are activated and begin the process of turning the stored food of the seed (starch)
into a usable substance (sugar).
- Sprouted barley, for example, actually contains the right amount of enzymes to be used in an effective cooking process.
- Most grains, however, lack the proper amounts or kinds of enzymes to permit rapid, self-contained, complete conversion.
- Consequently, such grains need to have enzymes, which are prepared from other sources, added to the cooked meal
- It's important to understand that starch is actually a complex sugar.
- Each starch molecule is a long chain of up to a thousand glucose molecules bonded either in a straight line or branching
like the leafless arms of a tree.
- Two enzymes are used to attack the "tree" at different points.
- Alpha enzyme attacks the branchpoints and reduces the tree into individual segments, while
- Beta enzyme attacks the ends of each branch and nibbles off individual glucose molecules.
- In order to make all the starch available for enzyme activity, the carbohydrate granules must be held at a rapid rolling
boil for 30 minutes.
- The heat causes the starch to expand and burst out of its cell wall, allowing our friends to get to work.
- (Traditionally, barley malt has been used as an enzyme source, and also -- in the brewing industry -- as a flavoring agent.
- However, today's industrially prepared enzymes are more consistent and considerably less expensive.)
- Mashing is basically a three-phase process which begins with the preboil.
- As the temperature approaches 150 deg F, the available starch begins to gelatinize, whereupon it is attacked by the alpha
enzyme (alpha-amylase) and reduced to a simpler carbohydrate.
- (The enzyme also serves to keep the mash from becoming too thick.)
- Subsequently, the mash is brought to a vigorous boil and held there for 30 minutes, to release all the remaining starch
- In the postboil stage alpha-amylase is reintroduced --
- since the enzyme is destroyed at 200 deg F and above --
- to hydrolyze any remaining starches into simpler sugars called dextrins.
- Once the mash has cooled to 90 deg F, yeast is added to the mixture, along with beta-amylase.
- The beta enzyme operates at the same temperature as the yeast and breaks down the dextrins to glucose for the yeast to
- During fermentation, the yeast produces its own internal enzymes.
- In fact, there are 11 separate internal stages that the yeast goes through while "brewing".
- Yeast is a faculative organism, which means that once it has begun to consume sugar, it has a choice between
two processes: to reproduce or to digest.
- If oxygen is present, the yeast will merrily bud itself ... but if oxygen is in short supply, the fungi will
produce waste in the form of carbon dioxide and alcohol.
- Therefore, it's best to agitate the fermenting mash for about ten minutes to encourage reproduction, and then cover it
up and let it stand
- Remember, you're dealing with a fairly sensitive biological process.
- So, follow all directions, be sure all supplies are kept in cool, airtight containers, and keep equipment clean.
- The numerous undesirable, microscopic sweet-tooths that can find their way into your mash will give you something,
but it won't smell too good, and you won't be able to put it in your gas tank.