Red Winemaking

Question 1

Factors that affect extraction

Answer 1

1) temperature
2) time on skins
3) if skins are mixed in
4) the medium its taking place
- tannins most soluble in alcohol
- anthocyanins most soluble in must

Question 2

Anthocyanins throughout winemaking

Answer 2

• they are the source of color in young red wines
• not stable as single molecules and can be lost throughout winemaking via lees/SO2
• when combined with tannins they are more stable, this happens with oxygenation (barrels etc)
• both anthocyanins and anthocyanin-tannins gradually turn paler then brown but the latter turns more slowly

Question 3

Transportation to winery for red grapes

Answer 3

They are less vulnerable to oxidation because of the phenolics in the grape skins but may still be chilled to slow oxidation and reduce threat of spoilage organisms
- may also be chilled if cold soaking is planned

Question 4

Steps to red winemaking

Answer 4

1) hand or machine harvest
2) transport
3) sort
4) destem and crush (vast majority)
- whole bunch
- pre-ferment maceration
- rose production
- press
5) alcoholic fermentation and maceration
- post-ferment maceration
- carbonic maceration
- punching down
6) drain (free-run juice)
7) press
8) malolactic conversion

Question 5

Crushed fruit fermentations

Answer 5

• when grapes are destemmed and crushed first
• pre-ferment adjustments to acidity, sugar, and tannin levels can be made

Question 6

Macerations before fermentation

Answer 6

The aim is to extract color and flavors without tannin
1) cold soaking
2) maceration using heat

Question 7

Cold soaking

Answer 7

• aka cold maceration / pre-fermentation maceration
• juice and skins are chilled to 4-10C / 39-50F (to reduce risks of oxidation, spoilage organisms, and spontaneous fermentation)
• typically lasts 3-7 days
• usually with punching down/pumping over (also avoids growth of spoilage organisms on the skins that need oxygen aka acetic acid
• very gentle with slow, easily controlled, extraction
• premium wines as it takes time and the energy to chill it

Question 8

Pre-fermentation macerations using heat

Answer 8

• bursts the cells in the grape skins allowing for rapid extraction of high levels of anthocyanins and flavors
• the longer at high temps the more risk of cooked aromas developing
• juice may be pressed off skins before fermentation if low tannin is desirable
• these wines tend to have issues with color instability as there isn’t enough tannin to bind with the anthocyanins so generally meant or inexpensive early-consumption
• said to increase fruitiness at risk of losing varietal characteristics
  1) flash detente: quickly heated to 85-90C / 185-194F then rapidly cooled under vacuum all within around 2 minutes ($$$)
  2) thermovinification: heating must to at least 50-60C / 122-140F for minutes to several hours

Question 9

Other than rapid color and flavors extraction, what are pre-ferment macerations using heat used for?

Answer 9

• the high temperatures denature oxidative enzymes (laccase) produced by grey rot/botrytis
• flash detente can treat smoke taint

Question 10

Macerations during fermentation

Answer 10

1) cap management techniques
2) must concentration
3) co-fermentation

Question 11

The vast majority of red wines are fermented ___ skins

Answer 11

On

Question 12

Why is cap management important

Answer 12

• in a tank of fermenting must the grape skins rise to the top and are buoyed there by CO2
• without mixing the skins would only macerate the same small volume of liquid surrounding them and it would become saturated and stop dissolving
• the dry cap would also allow for bacteria to convert alcohol into acetic acid
• aeration of the must also prevents reductive sulphur compounds
• helps to distribute heat created during fermentation

Question 13

Cap management techniques

Answer 13

1) techniques
- punching down
- pumping over
- rack and return
- gainmede tanks
- rotary fermenters
2) frequency and duration
3) the timing
- more mixing at the start = more color
- more mixing towards the end = more tannin
4) temperature
- warmer = more color
- cool temps toward the end of the= less tannin

Question 14

Punching down

Answer 14

• a hand-controlled or mechanized plunger is used to submerge the cap of grape skins into the liquid
• best for small, premium production as it is labor intensive and only possible in relatively small, open-top vessels
• gentle
• ‘pigeage’

Question 15

Pumping over

Answer 15

• juice/wine is taken from near the bottom and sprayed over the cap of skins (usuallly 1/3 to 1/2)
• extracts color, tannin, and flavors from the cap as it passes through
• so gentle that it often needs punching down to rack in return in addition
• can be allowed to splash to increase oxidation, beneficial for yeast health and avoidance of reductive off-flavors OR anaerobically in closed vessels
• common for black grapes
• can be done in large vessels and pre-programmed to decrease labor cost ($-$$$)
• remontage

Answer 16

• juice/wine is taken from near the bottom and sprayed over the cap of skins (usuallly 1/3 to 1/2)
• extracts color, tannin, and flavors from the cap as it passes through
• so gentle that it often needs punching down to rack in return in addition
• can be allowed to splash to increase oxidation, beneficial for yeast health and avoidance of reductive off-flavors OR anaerobically in closed vessels
• common for black grapes
• can be done in large vessels and pre-programmed to decrease labor cost ($-$$$)
• remontage

Question 17

Rack and return

Answer 17

• juice is pumped from one vessel to another the sprayed back over the remaining skins in the original vessel, breaking up the cap and mixing thoroughly
• very extractive, generally only done 1-3 times during fermentation alongside punching down and pumping over
• common for Cab Sauv and reds where medium to high tannin, flavor, and color are desired
• cannot be fully automated thus requires set up and monitoring labor
• requires empty vessels
• ‘delestage’

Question 18

Ganimede tanks

Answer 18

• specialized tanks that bubble CO2 up through the wine/must to burst the cap
• high levels of extraction similar to rack and return
• can be fully automated
• oxygen can be used in place of CO2

Question 19

Rotary fermenters

Answer 19

• horizontal, closed, stainless steel tanks that rotates and has spinning internal blades that break up and mix the cap
• horizontal orientation increases surface area in contact with the cap
• very effective at extracting therefore used for high tannin, color, and flavor grapes
• very low labor requirements but not gentle or precise thus often used for high-volume production of inexpensive or mid-priced wines

Question 20

Must concentration

Answer 20

• less common maceration during fermentation option
• drawing off some of the juice just after crushing to concentrate the remaining must (rose de saignée)
• lowers volume slightly

Question 21

Co-fermentation

Answer 21

• less common maceration during fermentation option
• fermenting different grape varieties together
• most commonly a small portion of white grapes in red fermentation (takes advantage of the phenolic compounds in white grapes that increase color intensity and stability through binding with anthocyanins + contributes aromas, can dilute)

Question 22

Whole berry/bunch fermentations

Answer 22

• aka uncrushed fruit with the objective of creating an oxygen-free environment
• the grapes change from aerobic to anaerobic metabolism, causing sugar to ferment to alcohol within the grapes without yeast (aka intercellular fermentation)
• malic acid in the grape breaks down to create ethanol, reducing malic acid by up to 50%
• glycerol levels increase, adding texture and creating kirsch, banana, bubble gum, cinnamon aromas
• can be entirely or partially uncrushed

Question 23

Stems in fermentation

Answer 23

• for whole bunches the stems must be ripe, can add herbal or spicy notes and tannins
• stems can also be added to crushed fruit fermentations
• not often used with grapes that naturally have high tannin levels

Question 24

Forms of whole berry/bunch fermentations

Answer 24

1) carbonic maceration
2) semi-carbonic maceration
3) whole berries/bunches with crushed fruit

Question 25

Carbonic maceration

Answer 25

- placing only whole, uncrushed bunches into vessels that are filled with CO2 to remove all oxygen causing intracellular fermentation to start - creates around 2% abv - grapes then start to split naturally or are crushed and normal fermentation begins, generally drained immediately and pressed allowing fermentation to occur off the skins - extracts color and a tiny amount of tannin - resulting wines are fruity, low tannin, and candied generally meant to drink early - can improve high yield grapes

Question 26

Semi-carbonic maceration

Answer 26

- a vessel is filled with whole bunches, the bunches at the bottom releasing some juice (due to gravity) and beginning fermentation and producing CO2 causing the remaining bunches to undergo carbonic maceration - the intact grapes will split and they will be pressed to ferment off the skins - may see punching down/ pumping over or oak if the aim is a wine with more concentration, body, tannin, and ageing capacity - contributes a smoother texture and more vibrant primary fruit aromas

Question 27

Whole berries/ bunches with crushed fruit

Answer 27

- intracellular fermentation occurs as the berries are submerged and kept away from oxygen - more whole berries = more carbonic characteristics

Question 28

Fermentation temperatures

Answer 28

Fruity/low tannin: 20C/68F Greater extraction: 30C/86F

Question 29

Fermentation vessels

Answer 29

1) stainless steel 2) concrete 3) wood 4) open to closed at the top

Question 30

Post-fermentation maceration

Answer 30

- can last from a few days to a few weeks - further extracts tannins and encourages the polymerization of tannins with the aim of improving tannin structure and ageing potential - premium and super-premium

Question 31

Pressing the wine

Answer 31

- pressing takes place when no more extraction is desired - flushing with inert gas is less common as red wine is more protected against oxidation - freerun then press fractions, often blended - for carbonic wines pressing takes place when 2% abv is reached & some are pressed after further post-fermentation maceration & some are pressed immediately after fermentation usually with the intention of fermentation finishing in barrel leading to better oak integration (variable compared to whites)

Question 32

Malolactic conversion

Answer 32

- routinely carried out for reds - malo in oak can lead to better oak integration - can take place during or after alcoholic fermentation - decreases acidity, increase pH - decreasing alcohol is possible at this stage

Question 33

Maturation in wooden vessels

Answer 33

- mid-priced or more expensive as it takes additional time and barrels - inexpensive reds tend to get spicy notes from staves or chips - typically between 6 months and 2 years - gentle oxidation (especially in small barrels) helps to soften tannins and lead to development of tertiary notes/ complexity

Question 34

Lees ageing

Answer 34

- softens tannins - reduces color intensity - racking used to seperate wine off lees and therefore control the amount of lees - typical to rack off gross lees - not typical to stir lees