Unit 2 sida 86-87 Flashcards
What is the epidermis?
The skin of the grape
what is the waxy and waterproof layer called? Created by the epidermis (skin)
Cuticle - also protects against some deceases
Just beneath the skin (epidermis) there is a specific kind of pulp, called?
The peripheral pulp - contains a high proportion of colored pigments, tannins and flavor compounds.
What else in the berry can tribute tannins?
The seeds - depending on the style of wine and choice of pressing method.
How is sugar transported to the berry?
By the stems mainly from leafs.
Name the main constituents of grapevine berry juice in %?
- 80% water
- 20% Sugar and other carbohydrates
- about 1% acids
- Phenolic compunds (about 0,1%)
what other minerals/salts are also present in grapevine berry juice?
Potassium and calcium salts
From what building block is the phenolic compounds created in the berries?
They are synthesised by sugars in the berry
Are there any differences between fructose and glucose since they are both present in grapes?
Yes, most grapes have slightly more glucose than fructose. It’s also easier to start/complete fermentation when there is more glucose than fructose, other then that they are mirror images of each other.
What is Pectin?
Pectin is a more complex carbohydrate molecule. Often/mainly more common in highly aromatic grapes (Viognier/Gewürztraminer) and in to high levels they can make it hard to clarify the grape juice.
Which are the two main acids found in grapes?
Malic and tartaric acid.
Other then malic and tartaric acid are there any others?
Yes, there is low levels of citric, ascorbic and acetic acids.
What does the phenolic compounds influence in the wine?
Color, texture, astringency and bitterness.
Catechins and epicatechins are smaller phenolic molecules upon oxidation what can happen with them present?
They can develop bitterness/ bitter taste upon oxidation
What is the name of the phenolic compounds responsible for red wines color?
Anthocyanins - found in the peripheral pulp
