Ch. 0 – Vinification Flashcards

Question

Sulfur Dioxide in winemaking

Answer 1

Preservative Anti-oxydant Anti-microbial - protects from yeast and bacteria Forms - gas (sulfur dioxide), liquid (potassium metabisulfite) or solid (potassium bisulfite) 10 mg/l naturally created by fermentation (more than this the label has to state that the wine contains sulfites) EU max. permitted 160 mg/l for red wines 210 mg/l for white wines Bound SO2 - SO2 which reacts with compounds in wine or must, Ineffective against oxidation Free SO2 - molecular form effective against oxidation Greater amount of SO2 has to be added to wines with high pH High levels of SO2 can dull wine aroma and flavours, eventually make the wine taste harsh

Answer 2

In small crates - minimal crushing, limited oxidation Large crates - some crushing (oxidation) adding SO2 ``` Minimising oxidation and microbial spoilage: Harvesting at night or sunrise Addition of SO2 Cold storage Sanitizing harvesting equipment ```

Answer 3

Sorting on conveyor belt or srew conveyor ``` Chilling Preserving fruit aroma, reducing microbial spoilage Slows down processing (higher cost) Possibility of heat exchanger Cost of energy and equipment ``` Sorting (triage) Better the sorting, higher the cost Labour requirement, lowering yield Sometimes MOG only (material other than grapes) Quality wine sorting: Removing unwanted grapes before picking or during hand harvesting Sorting by hand before and/or after destemming Optical sorting (expensive equipment) Destemming If stems are not ripe, they can convey green flavours and bitter tannins into wine Grapes not destemmed for: Red wine fermentation with whole bunches (Burgundy Pinot Noir) Carbonic maceration (Gamay in Beaujolais) Whole bunch pressing for some white wines (common for high quality sparkling wine) Crushing Gentle enough not to break seeds Combined crusher-destemmer machimes Grapes turn into must

Answer 4

Mixture of grape juice, pulp, skins and seeds

Answer 5

Pneumatic press ("air bag press") Cylindrical cage with bladder that inflates Can be programmed to different pressures Can be flushed with inert gas Basket press ("vertical or champagne press") Pressure applied from above, juice runs through holes on the sides of press, collected by tray on the bottom Not sealed vessel, cannot be flushed with inert gas Holds small loads Labour intensive Horizontal screw press Mounted horizontally, above rectangular draining tray Less gentle Requires batch processing Continuous press Allows grapes to be continuously loaded Less gentle

Answer 6

Solid remains of grapes left after pressing

Answer 7

Generally after must clarification for white wines Enrichment Usually before or during fermentation to raise alcohol Adding dry sugar, grape must, grape concentrate or rectified concentrated grape must (RCGM) OR concentration process - reverse osmosis, vacuum evaporation, cryoextraction (least expensive) EU is split into zone to indicate permited enrichment Reducing alcohol Adding water Only allowed in some regions ! also dillutes aroma, flavours, acids Acidification also used to lower pH Usually addition of tartaric acid Citric acid (not permitted in EU) Malic acid and lactic acid (used after malo) Before, during or after fermentation EU split into zones to indicate permitted acidification EU do not permit to both acidify and chaptalize Deacidification Adding calcium carbonate (chalk) or potassium carbonate Or using Ion exchange (expensive investment)

Answer 8

after Jean-Antoine Chaptal Adding dry sugar in form of beet or cane sugar

Answer 9

Freezing must (or even the final wine) and removing ice from it

Answer 10

Usually before or during fermentation to raise alcohol Adding dry sugar, grape must, grape concentrate or rectified concentrated grape must (RCGM) OR: concentration process - reverse osmosis, vacuum evaporation, cryoextraction (least expensive) EU is split into zone to indicate permited enrichment

Answer 11

Adding water Only allowed in some regions ! also dillutes aroma, flavours, acids

Answer 12

Also used to lower pH Usually addition of tartaric acid Citric acid (not permitted in EU) Malic acid and lactic acid (used after malo) Before, during or after fermentation EU split into zones to indicate permitted acidification EU do not permit to both acidify and chaptalize

Answer 13

Adding calcium carbonate (chalk) or potassium carbonate Or using Ion exchange (expensive investment)

Answer 14

Conversion of sugar into ethanol and carbon dioxide carried by yeast in the absence of oxygen (anaerobically) Also produces heat

Answer 15

Group of microscopic fungi that convert sugar into alcohol Initially they need oxygen to multiply quickly, but once oxygen is used they switch to fermentation They need: right temperatures, nutrients (nitrogen), absence of oxygen ``` Fermentation produces: Alcohol Carbon dioxide Heat Volatile acidity Small amount of SO2 Wine aromatics (from aroma precursors) Glycerol - increasing body of wine ``` Most common species of yeast is: Saccharomyces cerevisiae Can stand high acidity and alcohol, resistant to SO2

Answer 16

Aroma precursor Gooseberry aroma in Sauvignon blanc

Answer 17

Aroma precursor Linalool and geraniol - floral grapey aroma in Muscat

Answer 18

Aroma precursor Banana flavours in Beaujolais Nouveau

Answer 19

Saccharomyces cerevisiae Can stand high acidity and alcohol, resistant to SO2

Answer 20

Present in the vineyard and winery Range of species of yeast (Kloeckera, Candida) out of which most will die when alcohol reaches 5%. Saccharomyces cerevisiae will quickly become dominant Advantages: Add complexity by producing different aromas No additional cost Unique to place of origin - supporting terroir Can be used as part of marketing Disadvantages: Fermentation may start slowly (danger of build up of volatile acidity and spoilage yeast - such as Brett) Fermentation to dryness can take more time Increased risk of stuck fermentation Consistent product cannot be guaranteed

Answer 21

Also selected or commertial yeast Low levels of nitrogen can lead to stuck fementation and rotten egg smell from sulfur compounds Selected in laboratory, usually single strains of Saccharomyces cerevisiae Must has to be chilled (to surpress ambient yeast) or SO2 must be added to let cultured yeast to multiply. Started batch with cultured yeast is added to must to be fermented. ``` Advantages Reliable fast, fermenting to dryness Low levels of volatile acidity Less risk of spoilage Consistent product Large selection available - can affect the style of wine ``` Disadvantages Leads to certain similarity Adds cost

Answer 22

Nitrogen (prevents stuck fermentation and rotten egg smell) Diammonium phosphate (DAP) Thiamine (vitamin B1)

Answer 23

Cool 12-16 Fresher fruitier whites or rose Mid range 17-25 Easy drinking fruity reds with low tannin less fruity whites Warm 26-32 Powerful red wines Above 35 fermentation may slow down and stop

Answer 24

Temperature of the cellar Water or glycerol jackets that surround vessels Inserts put into vessels Reducing temperature by pumping over which releases heat

Answer 25

``` Stainless steel Easy to clean Range of sizes High degree of control over temperature Protection from oxygen High level of mechanization Initial investment ``` Concrete Inexpensive Maintain even temperature more efficiently Eggs - expensive set up currents which mix lees during maturation ``` Wood Retain heat well Attention to hygiene has to be paid Bacteria and spoilage organisms risk Small amount of oxygen Expensive when new oak is used ``` Alternatives Plastic (permeable to oxygen, difficult to control temp) Terracotta

Answer 26

Result of lactic acid bacteria converting malic acid into lactic acid and carbon dioxide and it produces heat. During and after alcoholic fermentation Encouraging conditions: 18-22 degrees moderate pH (3.3-3.5) low total SO2 Historically naturally started in spring when cellar warmed up, now lactic acid bacteria is added Avoiding it: adding enzyeme lysozyme (kills lactic acid bacteria) or filtering, keeping temperature below 15 Routine for red wine, choic for white wine ``` Outcomes: Redustion in acidity and raise in pH Colour loss in red wine Greater microbial stability (prevents malo spontaineously happening later) Modification of flavour (slight loss of fruit, adding butterly notes) Increasing volatile acidity ```

Answer 27

Acidity and pH can be adjusted Removal of alcohol Adding water to must (if permitted) Reverse osmosis - form of cross flow filtration which removed flavourless permeate of alcohol and water, which can be destilled to remove alcohol. Permeate is then blended back to recreate the wine. Spinning cone - First extracts volatile aroma compounds and then removes alcohol. Flavour components are then blended back into wine

Answer 28

``` Young aromatic fruity Protecting from oxygen Blanketing with so2 or inert gas Stainless steel Can be stored in bulk and bottled for final customer ```

Answer 29

Reduction in primary aromas, development of tertiary Influencing colour of wine Exposing young red to oxygen stabilizes colour Anthocyanins bind with tannins Softening tannins

Answer 30

Most exposure when doing transfers, rackling, lees stirring or topping up - when bung is removed Some wine is lost because it impregnate the wood and alcohol evaporates - gradual concentration of the wine Small vessels have large surface to volume ratio which encreases ageing, barrels need to be frequiently topped up (more exposure to oxygen)

Answer 31

Cheaper alternative without wood Bubbling oxygen through wine Increases colour stability and intensity, softens tannins, improve texture and reduce the presence of any unripe herbaceous flavours More quick, cheaper and can be controlled Oxygen in wine can provide environment for spoilage microbes such as acetic acid bacteria or Brettanomyces

Answer 32

White - 6-12 Red - 12-16

Answer 33

Age of the vessel New wood contains various extractable compounds Barrel looses about 50% of it new oak flavours during the first year New wood is used usually as proportion of blend Size of the vessel Greater extraction from wood and exposure to oxygen in small vessels Type of wood European (French, Hungarian, Russian, Slavonian) Imparts more tannin More expensive production (must be split in staves) American Higher levels of lactones (cocounut aroma) Greater aroma impart than European oak Can be sawn, grows faster Tightness of grain Oak from continental climates grows slower and the grain is tighter (slower extraction of compounds)

Answer 34

Wood seasoning Outside for 2-3 years. Lowers humidity levels in wood, increases flavour Cedar aromas Heating staves to bend in shape Transforms tannins and aroma compounds Toasting Light / medium / heavy toasted Aromas: spice, caramel, roasted nuts, char and smoke

Answer 35

Barrels are expensive to buy Minitoring costs Performing winemaking operations such as lees ageing is labour intensive with growing number of barrels Cleaning and sanitation (avoiding spoilage microbes such as Brett) Maturation is slow process adding on cost, return on investment is slow Alternatives: Oak chips or staves quick to have effect can be speeded up by micro-oxygenation

Answer 36

The sediment which settles on the bottom of the wine vessel (dead and dying yeast and bacteria, grape fragments, precipitated tannins, nutrients and other compounds) Gross lees (settled in 24h) and fine lees May be removed by racking

Answer 37

Yeast autolysis releases compounds contributing to flavours, body and texture. Some of these compounds bind with phenolic compounds in grapes, reducing colour and softening tannins. Also bind with wood components such as wood tannins (reducing astringency and modifying flavours from wood) White wine - yoghurt, dough-like, biscuit, toast aromas Helps with stabilization against unstable proteins (prevents hazes) Protect from oxygen, helping to maintain slow, controlled oxidation during maturation and reducing need for SO2. But if layer of lees is too thick, it can produce volatile reductive sulphur compounds. Lees provide nutrients for microbes so can help to grow lactic acid bacteria for malolactic fementaion (but also risk of Brett) Raised labour cost from monitoring and storing

Answer 38

Dying and breaking down of yeast

Answer 39

Process of transfering wine from one vessel to another with aim of removing sediment Can be oxidative process

Answer 40

Can happen at any stage but most common before finishing ``` Combining: Different grape varieties Different locations Different grape growers or sellers Different vintages Wine which has been treated differently Wine which has been treated equally for logistical reasons ``` Reasons: Balance - adjusting certain characteristics for balance Consistency - non vintage sparkling wine, cheap wine Style - ccertain house style, quality levels Complexity - greater range of flavours Minimise faults - diluting faulty batches Volume - bought grapes, different parcels Price - cheaper varieties Best carried before stabilization

Answer 41

Sedimentaton Centrifugation Fining Filtration

Answer 42

Natural clarification option Forming sediment on the bottom of the vessel which will be racked off The larger the vessel the greater the number of rackings needed Sedimentation avoids the loss of texture and flavour Long process, suitable for premium wines. If barrel maturation takes place sedimentation is part of the ageing process

Answer 43

Rapid spins to clarify wine. Can replace depth filtration and allow early bottling Only for high volume wineries

Answer 44

Fining agent is added to speed up the process of precipitation of suspended material in wine. The fining agent and the colloid attract each other and form a solid large enough to be removed by racking or filtration Clarifies the wine and helps to stabilize it. Can remove positive compounds or make the wine unstable if too much is added (over-fining) Each fining agent has particular properties which can offer solution to problems Protein or mineral origin 1) Agents that remove unstable proteins Betonite - form of clay, some colour loss in red wines Mainly used for whites (avoiding hazes) Protein in reds binds with tannins (clear wine) 2) Agents that remove phenolics (colour and bitterness) Egg white - fresh or powdered form able to remove harsh tannins and clarify Gentle, but must be declared on label Gelatin - Removes bitterness and astringency in red and browning in white easy to overfine (stripping flavours) Casein - Removes browing from whites and clarifies to some extent. Must be declared on label Isinglass - very effective for whites (bright appearance) Too much - hazes and fish smell (from fish bladders) Vegetable protein products - from potato or legumes PVPP - insoluble plastic in powder form Removes browning and astringency from oxidised white. Rarely used for reds 3) Agents that remove colour and off-odours Charcoal - removes brown colours (Pale Cream Sherry) and some off-flavours Overfines easily - stripping flavour

Answer 45

Separation technique used to eliminate solids from suspension by passing it through a filter or medium consisting of porous layers taht trap solid particles, thus making the liquid clear. The most common form of clarifying wine

Answer 46

Traps particles in the depth of the material that forms the filter. It can cope with fluid with many particles in it Does not block easily, however is not absolutely reliable Not absolute filter Diatomaceous earth (DE or Kieselguhr) pure silica, inert Rotary vacuum filters use it for very cloudy wine Oxidative process Enclosed DE filters can be flushed with inert gas DE comes in range of particle sizes Must be disposed responsibly (additional cost) Sheet Filters (plate, frame, pad filters) The more sheets, the quicker the filter Require initial investment

Answer 47

Includes tackling the potential for unwanted hazes, deposits in the bottle and rapid chanes in wine (browning). Protein stability Fining with betonite Tartare stability (potassium and calcium bitartrate) -4 degrees crystals form, then filtered only removes potassium bitartrate cost of cooling and equipment Contact process Quicker, more reliable, cheaper Wine cooled to 0 degrees, Potassium bitartrate is added to form cryslals and after 2h filtered Electrodialysis Charged membrane to remove selected ions High initial investment, low operation cost Both potassium and calcium ions Ion exchange Does not remove tartrates but replaces potassium and calcium ions with hydrogen or sodium ions It is not allowed in some territories Carboxymethylcellusose (CMS) Cellulose extracted from wood and prevents tartrates to develop to visible size Cheap and used on white or rose Not suitable for red as it reacts with tannin (hazing) Metatartaric acid Prevents growth of crystals The acid is unstable and effect is lost over time Microbiological stability Residual sugar - risk of refermenting. Removing yeast through sterile filtration or adding sorbic acid or SO2 Malolactic in the bottle (filtration or making sure malo was completed before) Infection with Brett (treatment with DMCD dimethyl dicarbonate - Velcorin)

Answer 48

Tartare stability (potassium and calcium bitartrate) -4 degrees crystals form, then filtered only removes potassium bitartrate cost of cooling and equipment Contact process Quicker, more reliable, cheaper Wine cooled to 0 degrees, Potassium bitartrate is added to form cryslals and after 2h filtered Electrodialysis Charged membrane to remove selected ions High initial investment, low operation cost Both potassium and calcium ions Ion exchange Does not remove tartrates but replaces potassium and calcium ions with hydrogen or sodium ions It is not allowed in some territories Carboxymethylcellusose (CMS) Cellulose extracted from wood and prevents tartrates to develop to visible size Cheap and used on white or rose Not suitable for red as it reacts with tannin (hazing) Metatartaric acid Prevents growth of crystals The acid is unstable and effect is lost over time

Answer 49

Residual sugar - risk of refermenting. Removing yeast through sterile filtration or adding sorbic acid or SO2 Malolactic in the bottle (filtration or making sure malo was completed before) Infection with Brett (treatment with DMCD dimethyl dicarbonate - Velcorin)

Answer 50

Surface filtration Stops particles that are bigger than the pore size of the filter. Absolute filter Membrane filters (cartrige) Slower, wine must be pre-filtered (easy to block) Sterile filtering Initial invetment is small, cartriges are expensive Cross-flow filters (tangential) Wine passes through filter while cleaning the surface of the filter as it goes Expensive machine, but no cartridges or sheets

Answer 51

Final full chemical analysis (at least alcohol, residual sugar and free SO2) right before bottling levels of dissolved oxygen and CO2 will be checked. ``` Adjusting levels of SO2 lower pH wine requires lower SO2 levels Generally white 25-45 mg/l red 30-55 mg/l sweet 30-60 mg/l ``` Reducing dissolved oxygen can accelerate ageing Sparging - flushing wine with inert gas to remove O2 ``` Adding carbon dioxide Added freshness (especially inexpensive white) ```

Answer 52

Flushing wine with inert gas to remove oxygen

Answer 53

Growth of yeast or bacteria Failure to filter adequately (or filtereing too fast) Wrong type of fining agent or over-fining ``` Remedy: Better hygiene Pre-bottling analysis Slow filtering Analysis after fining ```

Answer 54

Cloudiness and hazes Tartrates Re-fermenting in bottle Cork taint Oxidation Volatile axidity Reduction Light strike Brettanomyces

Answer 55

All wines have volatile acidity but high concentration results n smell of nail varnish or vinegar Activity of acetic acid bacteria, inadequate levels of SO2 and excess exposure to oxygen ``` Remedy: Sorting fruit to exclude damaged grapes Hygiene in winery Keeping vessels topped up Careful racking Maintaining adequate SO2 levels ```

Answer 56

Sulfur like smell (onion or rotten egg) Produced by yeast under stress (low nitrogen levels) or near complete oxygen exclusion during ageing in closed vessels especially when lees ageing Remedy: Assuring yeast have enough nutrients and oxygen Not overloading with SO2

Answer 57

Caused by UV radiation reacting with compounds in wine forming volatile sulfur compounds Odour such as dirty drain Wines which are left in direct sunlight or near fluorescent lightning are most in danger

Answer 58

Animal, spicy, famyard smell (complexity in low levels, high levels clear fault) Difficult to eradicate once it occurs. Wood is hosting the organism Keys to avoid Brett: Excellent hygiene Maintaining effective SO2 levels Keeping pH level low Keeping period between alcoholic fementation and malolactic conversion as short as possible

Answer 59

Final amount of oxygen in the container will determine the shelf life and expected development of the wine ``` Combination of: Dissolved oxygen in the wine Oxygen in the head space Oxygen in the cork or other closure Oxygen transmission rate (OTR) of the cork or closure ```

Answer 60

Glass No taint to wine and inpermeable to oxygen Near sterile conditions Inexpensive to manufacture and recyclable Best option for ageing High carbon footprint initially (heat for production) Heavy to transport and fragile Once open, subject to oxydation Clear bottles are susceptible to spoilage by light Plastic Light, tought, inexpensive, recyclable Must be lined with barrier to oxygen Special filling equipment required Bag-in-box Carboard box, flexible bag, aluminium foil as barrier Flexible pour size, range of container sizes Good protection from oxygen once opened Low environmental impact and easy to store Wine must have slightly higher SO2, low dissolved oxygen, no head space and low carbon dioxide level Shelf life 6-9 months Brick Tetra Pak Cardbord with plastic layers and aluminium foil Filling equipment is large investment Pouch Similar to bags inside bag-in-boxes Can Light weight, robust, easy to open, impermeable to oxygen and recyclable Aluminium has to be lined with plastic to avoid being attacked by the acidity of wine Large investment for filling equipment

Answer 61

Protect wine from rapid oxidation Be inert so that it does not affect the quality of wine Be easy to remove and re-insert Cheap, recyclable and free of faults

Answer 62

Light, flexible, inert, renewable, natural resource Positive image for consumers Variable levels of oxygen ingress - wine ages at different rates in the medium to long term Can house harmful fungi Can taint wine through the creation of TCA (2,4,6-trichloroanisole) about 3-5% of bottles Cleaning corks with stream extraction Recomposed cork particles cleaned and reconstituted with plastic Rigorous quality control during production Introducing barrier between the cork and the wine

Answer 63

Cork that has been subected to a manufacturing process Agglomerated cork (granules glued together) One-plus-one cork central part is agglomerated cork and sides are natural cork Diam cork Combination of cork and plastic Available in different ingress rates

Answer 64

Food grade plastic with silicone coating Difficult to re-insert in bottle Limited protection from oxygen Flavour scalping Plastic absorbs some flavour molecules

Answer 65

From tin (impermeable to oxygen) or Saran (form of plastic with low permeability to oxygen) Wines can become reductive after bottling - therefore lower SO2 levels should be used

Answer 66

Vinolok (brand name) Seal is formed by a plastic ring Special bottles must be used to ensure perfect fit As expensive as top quality corks

Answer 67

Increases cost Oxygen transmission rate of closure, oxygen in head space of bottle and dossolved oxygen in wine play key role on ageing (small amount of oxygen is beneficial) Low level of oxygen at bottling can result in volatile reductive sulfur compounds in wine (rotten egg) Undisrupted, cool, dark place with consistant temperature ideally around 10-15 degrees and constatnt humidity. If sealed with cork bottles should be lying down.

Answer 68

Hazard analysis of critical control points Identification of hazards, their seriousness and how to prevent them and correct them

Answer 69

Each consignment of wine will be given lot number which appears on bottle. EU requirement The winery must keep records of its activities at every point of production

Answer 70

Bulk Flexitank - single use, recyclable, polyethylene bag that fits into standard container ISO tank - stainless steel vessel built to ISO standards which can be reused Reefers - insulated tanks with temperature control Advantages of bulk shipping More environmentally friendly Cheaper Less fluctuation of temperature Reducing loss of fruit and oxidation Quality control can be analyzed better Wine can be adjusted at the final market before bottling Shelf life is extented (later bottling) Advantages of shipping bottles Producer has control over the entire product Disadvantages of shipping bottles Smaller amount of wine in one container, higher cost Weight of glass Potential damage, breakage, temperature, labels Shorter shelf life for inexpensive wine (bottled earlier)