Winemaking Flashcards
describe the influence of oxygen in wine making
a winemaker wanting to make a wine dominated by primary fruit, oxygen contact is kept to a minimum
grapes are harvested at night
when in winery juice is kept away from oxygen by filling airtight equipment with carbon dioxide or nitrogen - this is anerobic/protective winemaking
a question of winemaking style could be to keep oxygen contact for complexity and character
Describe influence of oxygen in maturation
wines matured aerobically - intact with oxygen are stored in oak
small amounts can interact with wine, softening tannins and giving more complexity of flavours, tertiary and secondary aromas develop
small vessels (225l barriques) have more contact with oxygen - smaller barrels rarely age for more than 2 years
oxygen effects can also occur if container is not completely full (olorosso, port, rutherglen muscat) - pronounced caramel, toffee, nut
what can extreme contact with oxygen do?
wine will lose fruit flavour become stale and oxidized being unfit for sale
can turn to vinegar
what acts as an antiseptic and anti oxidant
so2
strictly controlled by law
if too high wine can harsh and lack fruit
how does so2 act as an antiseptic vs antioxidant
anti septic - toxic to yeast and bacteria that is unwanted
anti oxidident - protects grapes and juice from oxygen effect - once doing this it becomes bound, losing effect so it needs monitoring and replenishing
oak tannins give?
structure and textural complexity
what is a con of oak?
hygiene - difficult to keep free from yeast, bacteria, mould
what does the heating of oak barrels do
transforms tannins and flavour compounds in the oak giving sweet spice and toast
the temperature and length of heat exposure affects this
how can you get a oxidized effect in wine with oak chips or staves
adding a small amount of controlled oxygen to the vessel
how can you regulate temperature in stainless steel vats?
sleeves on the outside or internal coils that cold or hot liquid can be circulated
pros and cons of concrete vats?
harder to clean and maintain
cheaper to regulate temperature
briefly describe the grape processing process
1) grapes arive at winery, receive first dose of so2 and are sorted and checked (for premium)
2) optional destemming and crushing, crushing releases free run juice but should be careful not to crush the seed releasing oil and tannin causing unpleasant and astringent tastes
3) pressing, separating liquids and solids
white wine happens before ferment
red wine happens after ferment
what is a pneumatic press?
inflatable rubber tube tube with a preferred horizontal stainless steel cylinder
this applies pressure to a large area in a controlled way, closed tank to keep away from oxygen
how can juice be seperated during pressing?
the juice at the beginning vs end of pressing is different in flavour and texture, it is seperated into different pressings called fractions and can be blended in different proportions to create a certain style
what 3 things may need adjustments in winemaking?
sugar, alcohol, acid
why may there be insufficient sugar in grapes?
cooler climates
what is RCGM
Rectified concentrated grape must
a colourless, odourless syrup that raises alcohol because there is more sugar to ferment
what is chaptilisation
adding sugar from sources other than grapes (eg: beet)
besides enrichment and chaptilisation, how can a winemaker raise sugar levels?
remove water from the juice
this concentrates sugar but also tannin acid and flavour compound and any faults, also reduces volume of juice
can you remove alcohol from wine?
yes with modern machinery