Common Elements in Winemaking / Maturation

L3

if choosing hands off approach, what two things can you avoid adding

cultured yeasts and sulfur dioxide

hands off approach can sometimes avoid what two processes

fining and filtration

only way stems can be gathered

hand harvest

why are antioxidants used

make sure primary flavours dominate

example of an antioxidant

sulphur dioxide

when to pick grapes to avoid contact with oxygen and why

at night, cooler so chemical reactions happen more slowly

name of adding co2 or no2 to airtight containers to reduce o2

protective or anaerobic

issue or not allowing any oxygen in winemaking process

can be bland and unintersting

two storage ways for anaerobic maturing

stainless steel or cement lined vats with epoxy resin

why are aerobic wines stored in oak

water tight not air tight

colour change of red wines when adding o2 through oak

red become paler and gain hint of brown

colour change of white wines when adding 02 through oak

white becomes deeper and orange hints

do smaller or larger barriques add more o2 contact

smaller

usually max time wine spends in barrique

2 years

what does can be done to barriques to enhance oxygen effect

leave them not completely full

3 wines you would not fill the container up fully for

oloroso sherry, tawny port and rutherglen muscat

3 tertiary flavours of these 3 wines

caramel, toffee, nuts

extreme case of too much 02

bacteria changes it to vinegar

effects on wine is so2 too high

harsh and lacking in fruit

when is some so2 naturally produced

fermentation

what does so2 become when can no longer bring protective effect

bound

what can so2 be toxic for sometimes

strains of yeast and bacteria

issue of using oak

hygine, difficult to keep free of yeasts, bacteria and mould

4 main factors to consider when choosing oak

species and origin, size, production, age

2 general oak species

american or european

where is generally considered to produce finest oak

forests in france

most important part in production of oak

toasting

what is heated and bent into shape in oak production

staves

3 aromas from heating / prod of barrels

toast smoke spices

two cheaper ways to add oak flavouring

staves or chips

two ways temp controlled on stainless steel

sleeves on outside or internal coils

what are concrete vessels usually lined with and why

epoxy resin inert and waterproof barrier

pros and cons of concrete over stainless steel

harder to clean but shells help regulate temp without need for expensive equipment

3 stages of grape processing

grape reception, destemming and crushing, pressing

what happens at grape reception

1st dose of so2, then sorted on table if premium wine

what does machine harvest remove

stems

name of juice released from crushing

free run juice

what should not be crushed and why

seeds as released bitter oils and tannin

what does pressing separate

liquid and solid constituents

when does pressing occur for white vs red

before ferm and after

region that uses vertical basket presses

champagne

more recent pressing machine

pneumatic

what is pneumatic press

inflatable rubber tube with perforated horizontal stainless steel cylinder

benefit of using pneumatic press

pressure over large area in controlled way

why can wine at start of pressing be separated from end and into what

different in flavour and texture into fractions

what is grape juice commonly referred to as

must

what is level of sugar in juice commonly named

must weight

what is added to grape juice if sugar levels not enough from cooler climates and what is process called

rectified concentrated grape must and enrichment

when can rcgm be added

before or during fermentation

is enrichment global

no it is banned in many parts of the world

other process of adding sugar from source other than grapes and name of stuff

chaptalisation and sugar beet

2 issues of removing water from juice

concentrates everything else including any faults and volume of wine is less to sell

when can modern machinery remove alcohol

after ferm

what is used for acidification and in what form

tartaric acid in powder form

what regions can acidification occur

warmer

what regions can deacidification occur

colder

yeast species responsible for most fermentations

saccharomyces cerevisiae

why is saccharomyces cerevisiae used

tolerance of high alc and so2

temp fermentation will not go below

5 / 41

temp fermentation will not go above

35 / 95

2 reasons yeast may stop fermenting

run out of nutrients (other than sugar) or if sugar and alc content too high

2 ways if deliberately want to kill off yeast before sugar all converted

adding so2 or adding grape spirit

how and when is yeast removed

filtration done after fermentation by dropping temp to 5

2 ways to control fermentation

choice of yeast and temp management

2 ways yeast can be found / added

ambient form on grape bloom or adding cultured yeast strain to must

pro of ambient yeast strain

complex flavours

con of ambient yeast strain

cannot control which yeast present so batch variation

name of cultured yeast strain

s cerevisiae

pro of cultured yeast

specifically selected due to attractive flavours

con of cultured yeast

argued to limit complexity

why ferment at lower temps

avoids loss of volatile aromas (often floral notes) and encourages fruity flavours

why ferment at higher temps

necessary for extraction of colour and tannin from black grapes

how can excess heat be released from ferm vat

pumping over