Winemaking Flashcards
What does the Skin of a grape contain?
Colour
Tannin
Flavour
What do the Pips and Stems of a grape contain?
High levels of Tannin
What is ‘Bloom’ and what does it consist of?
Bloom is the waxy surface covering the skin of the grape
It contains yeast and bacteria used to ferment wine
What is the Grape Reception and what are they treated with here it not first at picking time?
Where the grapes are received into the winery.
They are then treated with Sulphur Dioxide if not at picking
What two factors are optional are the Grape Reception?
Destemming and Crushing
What is an easy way to destem grapes before entering the winery?
Machine Harvesting
What happens if you want to remove grape stems inside the winery and what else can be done together with this?
A machine can be used which can also crush the grapes. It breaks the skin of the grapes
What the advantages and disadvantages of crushing the grapes?
Advantages -
Liberates a quantity of juice known as Free Run juice
Disadvantages -
Can put pips at risk of being damaged and release a bitter oil
Which two presses can be used to crush grapes?
Pneumatic
Horizontal
Referring to Adjustments in wine, what is Enrichment?
Adding sugar or removing water to raise alcohol level
Referring to Adjustments in wine, what is Acidification?
Carried out by the addition of tartaric acid in a powder form
Referring the Adjustments, what is De-Acidification?
Neutralising grape acid by adding chemicals such as Potassium Bicarbonate
Referring to Adjustments, what is Tannin?
Tannin can be increased by adding tannin powder or oak
What does Fermentation mean?
A chemical reaction brought about by action of yeast or bacteria
What is Alcoholic Fermentation?
The conversion of sugar and carbon dioxide into alcohol through the action of yeast
What happens if the temperature is below 5 degrees during alcoholic fermentation?
It will not start fermenting until above this
When does Alcoholic Fermentation stop and what is the average temperature of this?
When all sugar has been consumed or
When alcohol levels are so high that it kills the yeast
Usually stops at a temp of 15%Abv
What is another reason for Alcoholic Fermentation to stop?
If the yeast runs out of nutrients
What two things can a winemaker do to stop Alcoholic Fermentation?
Add SO2 to kill yeast
Chilling the must and filtering out the yeast
What is the most important yeast used and why?
Saccharomyces Cerevisiae
It can tolerate high levels of alcohol and SO2
It can create attractive flavours in wine
What can reduce complexity in the wine after Alcoholic Fermentation?
Yeast Strain
What other yeast can produce excellent flavours in a wine?
Ambient yeast
What is Malolactic Fermentation?
Carried out once alcoholic fermentation is done and done using lactic bacteria.
Converts Malic acids into Lactic acids
It can soften wines and reduces acidity
Do all red wines undergo MLF (malolactic fermentation)?
Yes