Common Elements in Winemaking and Maturation Flashcards
what happens during alcoholic fermentation?
yeast converts sugar in the grape juice to alcohol
What are wines that have very little human intervention?
natural wines
what is the process of oxygen reacting with grape juice called?
oxidation
If you want more fruit flavors in the wine, what is one way to obtain this?
decrease oxygen by using more sulfuric dioxide
why are grapes picked when its cooler?
it reduces the effects of oxygen because the chemical interactions are slowed in cooler temperatures
what is protective or anaerobic winemaking?
the process of filling an airtight vessel with either carbon dioxide or nitrogen before they are used for grape processing or wine making
How do you mature wines that have had no oxygen during the winemaking process?
oxygen should not be used during maturation process. either inert steel or cement vats should be used and kept airtight
what kind of vessels are wines that matured in contact with oxygen in?
typically oak - may be watertight but is not airtight.
what can oxygen do to wines during maturation process?
soften tannins, and give more complexity to the flavors, eventually giving tertiary flavors (leather and earth)
how long are wines typically kept in barriques?
no longer than 2 years
the technique of not filling the oak barrel completely to leave room for oxidation is done with what types of wines?
fortified wines Olorosso Sherry, Tawny Port, and Rutherglen Muscat - gives smells of toffee, nuts and caramel
how is sulfur dioxide used in a wine?
acts as an antioxident and antisepti. It protects newly harvested grapes. wines can become harsh if too much used
what happens when SO2 protects the grape juice and wine from oxidation?
it becomes “bound” and can no longer have a protective effect
what kind of flavors does oak give to wine?
toast, vanilla, smoke and cloves
what are the four specific factors winemakers need to consider when looking at oak
- species and origin of oak
- size
- production of oak barrels
- age
why do smaller barrels have more impact on wine?
more of the wine is in contact with the surface of the barrel
what is one of the most important parts of the production of an oak barrel?
toasting it
what are some effects of heating an oak barrel?
the staves bend into shape, transforms the flavors and tannins (notes of toast and spice) and the amount of heat will (level of toasting) affects the flavors contributed to the wine.
What happens to a barrel after it is toasted?
the time each barrel can be used is diminished (the younger the barrel the more the flavor)
What are some alternative to oak barrels that can be used to still get oak flavors?
small planks of oak (staves), oak chips, or even adding small quantities of oxygen to the barrel
what is an inert vessel?
one that is not made of wood. Can be stainless steel or concrete. they do not add any flavors on the wine or allow oxidation.
why are stainless steel vessels used?
not to allow any new flavors in the wine and also easy temperature control
Why are concrete vessels used?
they are lined with epoxy resin which provides a waterproof barrier. not used frequently any more and most have been replaced by stainless steel
when do grapes receive their first dose of SO2
when they arrive at the winery