Chapter 2: Preparing Raw Materials Containing Fermentable Sugars Flashcards
Explain how photosynthesis works.
Plants use the energy from sunlight to convert water and carbon dioxide (CO2) into sugar and oxygen.
In what part of the plant does photosynthesis mostly take place in?
The leaves.
Which two types of sugar are made in plants during photosynthesis?
Glucose and fructose.
How is sucrose made in plants?
By bonding together one molecule of glucose and fructose.
How does a plant use the sugars it produces? (2)
- It combines the sugars with other nutrients they take up from the roots to build plant structures.
- Sugar is an efficient way to store energy.
Why does yeast require sugar in order to create alcohol?
Sugar is the energy source that yeast uses to create alcohol during fermentation.
What are the 2 problems a distiller faces when handling a raw material that is full of sugar?
Spoilage and oxidation.
Explain how a raw material containing sugar might become spoiled? (2)
- Loss of yield caused by animals and microorganisms eating the raw material.
- Partly eaten raw materials run the risk of being tainted and rendered unusable. Typically caused by fungi and bacteria.
Explain oxidation.
Oxygen reacts with raw materials (fruits, sugar cane) and with the juices they release causing a loss in (1) sugar yield and (2) inidentifiable and expressive aromas.
Give an example of oxidation.
When you bite into an apple the area exposed becomes brown and starts to lose its freshness, ultimately tasting unpleasant.
What preservative chemical might be used in cider and wine production to protect fruit juice from spoilage and oxidation?
Sulfur dioxide (SO2).
Why is it not advisable for distillers to use SO2? (2)
- High levels of sulfur compounds become unpleasant smelling when consentrates during distillation.
- Adding sulfur before or during fermentation presents real dangers to the health and safety of staff.
How might distillers minimize the risk of spoilage and oxidation? (2)
- Ensuring a short time period between harvesting and the onset of alcoholic fermentation. The yeast is able to fend off microorganisms.
- Blanketing the raw material in gas (typically CO2), as gas is denser than air and it would naturally cover the raw material, blocking out any oxygen.
In order for a fruit to be commercially important, what criteria should it meet? (2)
Fruiting plant needs to:
1. Be domesticated
2. Provide a usable quantity of sugar-rich juice
Which are the most widely used fruit species in alcohol production? (3)
Apples, pears and grapes.
Explain the two stage process to releasing fruit juice.
- Fruit is fed through crusher, releasing some of the juice.
- Crushed fruit is pressed to release remaining juice.
What is pomace?
Grape skins and stems left from winemaking.
Which grapes are white wines commonly made of?
White grapes.
What grapes are red wines made from?
Black grapes.
Where does red wine get its dark color and much of its flavor from?
From the grapes’ skins which are included in the fermentation process, but then pressed to extract the remaining juice and discarded.
How might be white grape pomace handled?
It may be delivered to a distillery where the distiller ferments the residual sugars in order to create alcohol.
How might black grape pomace be handled?
Black grape pomace typically already contains some wine (alcohol), so distillation could take place immediately if it were delivered to a distillery.
What type of sugar is found in the stems of the sugar cane plant?
Sucrose
How is sugar cane processed?
The stems are broken open, shredded and crushed to extract sugar cane juice.
What is bagasse?
Plant fibres left behind from the extraction of sugar cane juice.
How can bagasse be used in the sugar refinery?
As fuel to supply power to the refinery.
How is sugar cane juice treated before the refining process? (2)
Its is (1) pasteurized to kill any unwelcome bacteria and fungi.
And (2) clarified to remove impurities and suspended oils.
What is the first step to creating sugar and molasses?
Creating cane syrup by evaporating water off of sugar cane juice.
What equipment is used in processing cane syrup? And how does it operate?
Pan boiler. If operates under partial vaccuum conditions.
How are A-sugar and A-molasses produced? (3 steps)
- Cane syrup is mixed with sugar seed crystals.
- The mixture is heated in the pan boiler. As water evaporates off some of the sucrose can no longer stay in solution and starts to build around the seed crystals.
- The mix of liquid and sugar crystals pass through a centrifuge, separating the sugar crystals from the syrupy liquid.
When, during the sugar production process is the highest quantity of sugar extracted?
When A-sugar is produced.
Describe the quality of A-sugar?
Highest quality with the least impurities.
How are B-sugar and B-molasses produced?
- A-molasses are mixed with more sugar seed crystals and moved to the second pan boiler, then the mixture is boiled.
- Sugars are separated from molasses using a centrifuge.
Describe the quality of B-molasses and B-sugars.
There’s a higher quantity of impurities. B-molasses are thicker and darker in color.
How are C-sugars and C-molasses produced?
- B-molasses are mixed with more sugar seed crystals and moved to the third pan boiler, where the mixture is boiled.
- The mixture is centrifuged to separate the two products.
How is C-sugar used in the refinery?
It’s used to form the seed crystals for future batches.
How are C-molasses used in the refinery?
They are usually a by-product as they have a very high level of impurities. C-molasses are very dark, viscous and hard to work with.
C-molasses are also known as…
Blackstrap molasses
A- and B- sugars are also known as..
Brown sugar
What are are the flavors/aromas of brown sugar? (2)
Toffee and Caramel.
How is white sugar made?
By further refining brown sugar.
