Level 4 D1 Chap 16 - White Winemaking Flashcards
How does machine harvesting compare with hand harvesting, in the process of must production for white wine?
Machines harvest berries only, whereas hand harvesting takes whole bunches.
Therefore hand harvesting must decide whether to de-stem before crushing and/or pressing
What are the key decisions to be made in white wine production up to the point of “newly made wine”?
1 harvest method 2 sorting level 3 de-stem? (hand Harvest only) 4 crush? 5 skin contact time? 6 press method / pressure 7 hyperoxidation? 8 clarification level/method 9 must adjustments (alcoholic fermentation) 10 post-fermentation adjustments 11 MLF?
What white varieties are most likely to have skin contact? Why?
Aromatic varieties: Reisling, Sauvignon Blanc, Viognier, Gewurtztraminer, etc
Maximizes flavor extraction and enhances texture through small amount of tannin
Since oak use is rare with these grapes, skin contact enhances texture of wine
What impact does skin contact have on white wine?
- potential enhancement of aroma and flavour compounds
- enhance the texture through small amounts of tannin
If excessive, can lead to bitter taste and coarse feel
How long are white grapes left with skin contact? Anything else specific about the process?
Skin contact is typically 1-24 hours
Juice is typically chilled to below 15°C
What is orange wine and how is it made?
Orange wine is made from white grapes and normally fermented on skins, resulting in a larger component of oxidised compounds from the skins.
Orange wines are usually dry, tannic, with tertiary flavours such as nuts and dried fruit.
In more detail, what are the impacts of the choices of the winemaker with white grapes up to and including pressing?
Hand picked grapes can be destemmed and / or crushed before pressing.
Whole bunch pressing can be used for premium wines
Inert gases can limit oxygen exposure during these phases
Free run juice is from crushed grapes – or the first press fraction
More pressure will result in press juice with increased solids, tannin and colour.
What is hyperoxidation and when is it used?
Hyperoxidation is deliberately exposing must to large quantities of oxygen before fermentation.
It is used to produce a wine that is potentially more stable, and removes some bitter compounds.
It can destroy some aroma compounds and so is better with neutral grape varieties, e.g. Chardonnay
Why is white grape must clarified?
What are the methods by which clarification is done?
Clarification of must is optional prior to fermentation. It reduces the risk of spoilage from solids and their reactions
Overall the range of aromas may be reduced by clarification. However it thought to obtain better fruity aromas
It is usually carried out by one of:
- Sedimentation – 12-24 hours (traditional but takes time & space) Must is cooled to 4 degrees. MUST and WINE
- flotation of solid matter from bubbling inert gas through must, with a fining agent, to skim off MUST ONLY
- centrifuge (expensive equipment but can handle large volumes) MUST and WINE
- clarifying agent such as pectolytic enzymes (MUST and WINE depending on agent)
When is white wine fermented in oak?
Small oak barrels are typically used for premium/ super-premium, non-aromatic grapes, particularly Chardonnay
What temperatures are used for white wine fermentation?
12°C - 16°C for fresh fruity wine - esters are maintained.
If you don’t want fruity flavors, the temp may be increased to 17°C -25°C to avoid production of esters like isoamyl acetate (banana-like smell)
What white wines are matured in wood?
Neutral, non-aromatic varieties may be matured in wood, particularly premium/ super-premium wines
What winemaking processes or decision points are there when maturing and finishing white wine for sale?
12 blending 13 use of oak in maturation 14 lees ageing 15 further blending 16 stabilisation 17 clarification 18 packaging
What is the potential impact of lees ageing on white wine?
- soften mouthfeel (improve texture)
- increased body/depth
- stabilise
- protect from oxygen
- introduce some reductive sulphur compounds
What is the french word for lees stirring?
Bâtonnage
