Specific Options for White Winemaking Flashcards
Describe the process of skin contact
Skin contact is the process of leaving the juice in contact with skins to extract compounds from skins.
What is the main purpose to carry out skin contact on whites grapes
Main purpose is to extract aroma and flavour compounds/precursors
Enhance texture of wine by extracting small amount of tannin
The majority of white wines are made with or without skin contact
Without skin contact - or very minimal
What type of grapes is skin contact more effectively used on
Aromatic grape varieties with lots of aroma compounds
Riesling, Gewurztraminer, Viognier, Muscat, Sauvignon Blanc
How long is skin contact done for white wines and at what temperature
1-24 hours
Juice chilled to below 15C
Describe the hyperoxidation technique
Technique of deliberately exposing must to large quantities of oxygen before fermentation
What is the main aim of hyperoxidation
To produce wines that are more stable against oxidation after fermentation.
Can help remove bitter compounds from unripe grape skins, seeds and stems
List the clarification of must techniques used for white wines
Sedimentation (settling) - simplest form
Flotation
Centrifugation
What is the aim of clarification of must
Reduce the amount of suspended solids within must.
What percentage do winemakers aim for the proportion of solids in the must
0.5-2.0%
Most winemakers choose to retain 1-2%
How do proportion of solids in must reach levels below 1%
Pectolytic enzymes
Centrifugation
Describe the clarification technique floatation
Involves bubbling gas up through must - bring solid particles to top
Solid particles skimmed off the top of the vessel
Speeds up rate of clarification compared to sedimentation
Inert gas (nitrogen)
Requires gases, fining agents and equipment for bubbling gas through liquid
Continuous or batch process
List the clarifying agents used to speed up the rate of sedimentation in white wines
Pectolytic enzymes
Fining agents
Describe what pectolytic enzymes are
Break down pectins - naturally found in plant cell walls (used in jam)
Breaking down pectins allow more rapid separation between liquid juice and solids
Only aid clarification of must, not wine
What are the fermentation temps for white wines
Fruity white wines - 15C
Oak - 17-25C
What are the effects of MLC
Reduction in acidity, increase pH
Increase microbiological stability
Modification of flavours in wine
Is MLC recommended for low-aromatic varieties like Chardonnay?
Choice - can provide greater complexity
Is MLC recommended for aromatic varieties like Riesling?
MLC usually avoided to preserve primary aromatics
What kind of white wine can maturing in oak barrels be beneficial?
Premium and super-premium wines made from low-aromatic varieties like Chardonnay
Adds texture and complexity
What kind of white wine is it not recommended to mature in oak barrels?
Aromatic grapes
Inexpensive wines
What is the aim of lees ageing in wine?
Give more body
Soften mouthfeel
Help stabilize the wine
Protect wine from oxygen
May introduce reductive sulfur compounds
