16. Specific Options for White Winemaking Flashcards
Why would a winemaker choose to block MLF for certain WHITE varieties and not others (3)?
MLF has a significant effect on the style of the final wine produced.
- Low-aromatic grapes, e.g. Chardonnay, are more often put through MLF in order to increase perceived complexity + achieve a recognizable style.
- Aromatic, high acid grapes, e.g. Riesling, Sauvignon Blanc, will typically avoid MLF in order to retain signature acid+aromatics.
What are the PROS (3) and CONS (3) of retaining a significant portion of solids in the must before fermentation?
What type of wine is this process most suitable for?
PROS: - adds texture, subtle astringency.
- gives a greater range of aromas from fermentation = complexity.
- provides nutrients for yeast, reducing risk of stuck fermentation.
CONS: - supresses fruity aromas, so less suitable for e.g. inexpensive Pinot Grigio.
- needs careful monitoring + management = labor$$$
- if too much, reductive sulfur compounds can develop = aromas of rotten egg, onions.
More suitable for wines w/less fruit-forward flavors, e.g Premium Chardonnay.
In addition to employing whole bunch pressing, what can winemakers do to reduce the chance of oxidation during pressing (3)?
- Use a closed press, i.e. pneumatic, vs an open press, e.g. Basket press.
- Flush the press w/an inert gas such as nitrogen or CO2.
- Use dry ice (solid form of CO2) in the press.
What are the PROS (2) / CONS (2) of Batonnage as a method of lees stirring?
PROS: increases release of yeast compounds in wine / increases oxygen exposure (decrease of fruity flavors, decrease of sulfur compounds)
CONS: oxygen exposure might not be desired / labor intensive = $$$
What are 4 methods to clarify white wine must?
When is clarification of MUST carried out?
What is its purpose?
1) sedimentation
2) flotation
3) centrifugation
4) clarifying agents
Carried out btw/pressing and fermentation.
Purpose = reduce amount of suspended solids + particles of skin/stem/seeds.
What effects does lees aging have on white wine (5)?
- gives more body
- softens mouthfeel
- helps stabilize
- protects wine from oxygen
- introduces sulfur compounds which can contribute pleasing aromas (struck match, smoke) at low levels.
Why would a winemaker choose to ferment white wine in Concrete or Old Oak Vats?
What are some typical examples of white wines fermented this way (2)?
- used for fermenting white wines at slightly warmer temps, where maximizing fruity/floral aromas is not key.
e. g. some Chablis and white Rioja.
What are PROS (4) and CONS (3) of Flotation for clarifying must?
PROS: - faster than sedimentation.
- if oxygen is used (vs nitrogen), the process doubles as hyperoxidation.
- effective+quick, can be used continuously or in batches.
- Saves on energy costs (no chilling)
CONS: - Fining agents must be added to bind particles.
- Only effective for must, not wine.
- extra costs: gases, fining agents, equipment.
What are the cost implications of using hyperoxidation (2)?
- cost of equipment required is not very high.
- however, it does add extra time to the winemaking process, requires labor to monitor and set up, so it may have a small impact on costs.
Fill in the blanks for white wine production
(grapes to newly-made wine):
Why would a winemaker choose to ferment white wine in stainless steel (2)?
What are some typical examples of white wine fermented this way (2)?
- most popular choice for fruity, floral white wines.
- ability to control/maintain cooler fermentation temps required.
- e.g. Sauvignon Blanc and Veneto Pinot Grigio.
What are typical fermentation temperatures for white wines, depending on the style desired (2)?
What does fermenting at a warm temperature help with?
- 12-16 degrees C if fruity aromas/flavors are desired
- 17-25 if fruity aromas aren’t desired
1) promotes yeast health
2) avoids production of esters e.g. isoamyl acetate (banana smell)
What is an example of a clarifying agent used for white wine must?
How does it work (2)?
What are PROS (2) and CONS (2)?
e. g. Pectlytic enzymes which break down pectins in must.
- pectins = naturally occuring substance in plant cell walls.
- breaking these down = more rapid separation btw/liquids and solids.
PROS: - speeds up clarification process.
- saves time and energy vs sedimentation.
CONS: - only works on must, not wine.
- cost of purchasing.
What is free run juice?
What are its characteristics?
What is a financial consequence of using ONLY free run juice to make wine?
Juice drained off as soon as grapes are crushed (lowest in tannin and colour)
- reduces final vol. of wine = cost implication.
What is hyperoxidation (2)?
What is its purpose (2)?
- a process of deliberately exposing the must to large quantities of oxygen before fermentation
- turns easily oxidized compounds brown, then during fermentation they precipitate, turning wine to original colour.
- aim is to produce wines that are more stable against oxygen after fermentation
- also removes bitter compounds that come from unripe grape skins, seeds + stems.
Why is the majority of white wine made with zero/minimal skin contact (5)?
- principle desired aroma/flavor compounds of white grapes are in the pulp.
- Most winemakers want to make white wine w/fruity flavors, minimal color and a smooth mouthfeel; extra tannins/flavors/texture that skin contact will impart are not wanted.
- skin contact not ideal for early-consumption wines because tannins would not have enough time to soften.
- skin contact w/under-ripe fruit can especially give bitter flavors and astringent tannins.
- slows processing, requires equipment+labor.
How do Time and Temperature influence extraction during skin contact for WHITE wines?
What is the normal practice for each?
More time = greater extraction of flavor+tannins
Normal time for skin contact = 1-24 hours.
Cooler temps = less extraction of flavors+tannins
Typically chilled to below 15 C / 59 F.
What is flotation (2)?
- a must clarification method that involves bubbling gas (usually nitrogen) up through must
- as bubbles rise, they bring the solid particles with them which are then skimmed off top of vessel
What are the PROS (2) and CONS (2) of Sedimentation for White Wine clarification?
What type of wine is this process most suitable for?
PROS: - cheapest in terms of equipment required.
- no extra equipment+additives required
CONS: - takes more time+labor
- energy$$$ for chilling
Most suitable for small-batch, premium wines.
What steps can winemakers take to minimize skin contact when making white wine (2)?
- Pressing immediately after crushing.
- Using whole bunches of uncrushed grapes.
Give a specific example of a white wine whose style is well-suited for barrel maturation, and one that isn’t:
Premium/Super-Premium Chardonnay from Burgundy; low aromatics+neutrality = better medium for the textures, aromas and flavors that oak/oxygen can bring.
Clare Valley Riesling; aromatic, high acid wine that would clash with vanilla/toasty/nutty flavors from oak+oxidative aging.
What types of white varieties is hyperoxidation more/least suitable for?
Why?
Most suitable for neutral varieties, e.g. Chardonnay.
Least suitable for aromatic varieties, e.g. Sauvignon Blanc.
Hyperoxidation can destroy most volatile aroma compounds, such as thiols and methoxypyrazines in Sauvignon Blanc.
What are the PROS / CONS (2) of Automatic Systems as a method of lees stirring?
PROS: gives winemaker more control over impact of lees/oxygen.
CONS: increases likelihood of sulfur compounds developing / not as effective as manual stirring/agitating.
Sedimentation is the ___ and ____ method of clarifying white must.
Explain the 3-step process of sedimentation as a means of clarification for white wines.
- simplest (and cheapest) method of clarifying must.
- must is chilled to around 4 C / 39 F to reduce oxidation+microbial spoilage and (avoid spontaneous fermentation of must.)
- suspended solids are left to fall over time (12-24 hours)
- clear juice is racked into fermentation vessel
