D1: General winemaking options

Question 1

Oxygen is responsible for a number of reactions that occur between the compounds in grape must or wine and for this reason can have a significant effect on wine style and quality.

Answer 1

Although oxygen itself is not very reactive with many compounds in must and wine

The reaction it does take part in create products that then go on to react with many must and wine compounds

— these reactions are oxidation reactions

• the timing and amount of oxygen exposure is key, making the difference between positive or negative effect
• • an understanding role of oxygen is essential

Question 2

why isoxygen a general threath for the production of fresh fruity winestyles ?

Answer 2

1) many of the aroma compounds that give these wines their fruity character, (eg thiols in sauv b) break down in the presence of oxygen
- – this can lead to a loss of fruitiness

2) The products of oxidation may contribute to unwanted aromas to the wine: ex: acetaldehyde (from the oxidation of ethanol)
- – can give the nutty apple aroma

Question 3

What does oxidation do with the color of the wine ?

Answer 3

1) White wines: turn darker, becoming gold and then brown with increased oxidation
* therefore white wines tend to need greter protection

2) phenolic compounds in red wines have an anti-oxidative effect, which means that they can absorb more oxygen before such effects are perceptible

Question 4

How is the practice of minimising oxygen often called ?

Answer 4

Reductive or protective winemaking

Question 5

How can the effect of oxygen to the must of wine be limited ?

Answer 5

1) avoiding ullage in vessels:
- - ullage is the headspace of air between the wine and the top of the container
- it can be avoided by:
* ensuring vessels are filled to the top
* if using wooden barrels there may be a gradual loss of liquid through evaporation
- - therefore, these vessels should be topped up regularly with more wine to avoid ullage

2) Use of inert gases: nitrogen, carbon dioxide and argon can be used to flush out oxygen from vessels, pipes and machinery (presses)
- - these gases do not react with compounds in the wine
- - can also be used to fill up the empty headspace of any containers where the wine does not reach the top to prevent oxygen coming into contact with the wine

3) add of so2

4) use of impermeable containers: stainless steel r thick concrete vessels are impermeable to oxygen
- - glass bottles with screw cap also minimise exposure to oxygen during storage in bottle

5) cool constant temp: slows the rate of oxidation reactions
- - hence the reason for maturing wines in cooler conditions
- - or picking grapes in the night or early in the morning so that the fruit is not warm

Question 6

How can controlled oxidation be positive for the wine ?

Answer 6

1) oxygen is required at the start of fermentation of all wines to promote growth of a healthy yeast population and, in some cases
- – lack of oxygen in winemaking or storage can lead to reductive off flavours (fault)

2) in production of white wines: exposure to oxygen before fermentation is thought to lead to greater oxidation stability of the wine
- — increases age potential (hyperoxidation)

3) red wines: oxygen is essential in the reaction of anthocyans and tannins
- – this leads to greater color stability

Question 7

what can oxygen do to the aromas of the wine over time ?

Answer 7

1) it can give a greater range and diversity of characteristics:
* fresh fruit becomes dried fruit and notes such as honey, nuts, caramel, coffee, leather and mushrooms

2) a high level of oxidation is vital in some wine styles, such as olorosso sherry, madeira and tawny port
3) less extreme oxidation also contributes to the complexity of many matured white and red wines

Question 8

How can oxygen exposure be increased ?

Answer 8

1) use of cap management techniques in red wines fermentation that spray or splash the must/ wine
2) use of small wooden barrels that only contains a small volume of wine relative to the ingress of oxygen through the bung, holes and staves

3) increasing the number of rackings or amount of lees stirring during ageing:
- - any procedures where the bung or the lid of the barrel or vessel need to be removed and the wine to be moved
* increases the oxygen exposure

4) allowing ullage in wine containers without use of inert gases
5) pumping over

Question 9

Oxygen can favour the growth of spoilage microbes, such as:

Answer 9

1) acetic acid bacteria
2) brettanomyces

– especially if other conditions are favourable ( grape must or wine with residual sugar

• therefore wines exposed to oxygen must be carefully monitored for these microbes and their associated faults

Question 10

Sulfur dioxide is a preservative (voorbehoedend) and it acts like:

Answer 10

1) Anti oxidant:
- only reacts with oxygen itself very slow
- - it reduces the effect of oxidation by reacting with the product of oxidation reactions
- — so they cannot oxidise further compounds in the wine
* it also inhibits (remt) oxidative enzymes

2) anti microbial:
- - inhibits the development of microbes such as yeast and bacteria
- — different species of yeast and bacteria can vary in their tolerance to so2

Question 11

so2 can be applied in many forms:

Answer 11

gas liquid or solid:

— as sulfur dioxide, potassium metabisulfite or potassium bisulfite

Question 12

what about the amounts of so2 ?

Answer 12

1) small amount is naturally produced during ferm (10mg/l or less)
2) max concentrations are defined by local laws as it is a toxic substance
ex: eu 160mg/l is the max permitted for red wines and 210 mg/l max for white
* sweet wines are permitted to contain higher levels

3) the max permitted levels are lower for organic wines than non organic (usa so2 is forbidden for organic wines)

4) The concentrationof so2 found in wines are far below toxic levels
however some people experience an allergic reaction even at this low levels

5) if a wine contains over 10 mg/l, the label must state that the wine contains sulfites

Question 13

When adding so2 ?

Answer 13

1) generally soon after the grapes are picked and or reach the winery
2) it may be added at various points during the winemaking process and usually at bottling

Question 14

What kind of forms does so2 haves ?

Answer 14

1) when added to must or wine it dissolves and some of it reacts with the compounds in the liquid
- – this proportion is called bound so 2
* ineffective agains oxidation and microbes

2) the proportion that is not bound is called free so 2:
- - the vast majority of free so2 is in a relatively inactive form
- —- small proportion exist as molecular so2 which is the most effective against microbes and oxygen

Question 15

What about the ph level and so2 ?

Answer 15

1) the ph level of must or wine has a key effect on the efficiacy of so 2
- - a greater proportion of so2 is in the molecular form at lower ph levels
* this means a greater amount of so2 need to be added at higher ph level to protect them from oxidation and microbes

Question 16

And what about timing and size of so2 additions ?

Answer 16

Adding a larger amount when the grapes are crushed, ad the end of malolactic conversion and at bottling is considered more effective than adding smaller amounts throughout the winemaking process

Question 17

Judicious add of so2 are benfical and often necessary to produce unfaulty wines that remain unfaulty once packaged. however where possible quality conscious winemakers will aim to limit add of so2 both because of the legal restrictions listed above and because:

Answer 17

high levels of so2 can dull (saai) aromas and sometimes cause the wine to taste harsh

Question 18

How can you reduce microbial invasion in winery and reducing the amount of additional so2 ?

Answer 18

1) good winery hygiene and effective grape sorting can limit the amount of harmful microbes in the wine and winery
2) limiting oxygen exposure and keeping grapes/must/wine at coll temp can also reduce the amount of so2 needed to protect from oxidation and microbial spoilage

Question 19

what are the options to transport the harvesed grapes to the winery ?

Answer 19

1) small crates: quality purpose or small scale grapegrowing
- - small crates means minimal crushing of grapes and therefore limiting oxidation and microbial spoilage

• • small crates are tipped into larger hoppers (large bins) for transport
• without protective measures this would involve some crushing of the grapes and therefore oxidation and potentially microbial spoilage
• — some grapegrower will add so2 at this moment and in the form of Potassium metabisulfite

2) machine hharvested fruit has already been destemmed and is therefore transported as grapes in larger containers with some release of the juice again microbial spoilage and oxidation
- – so adding so2 at this moment (especially for the larger estates)

Question 20

Once grapes have been picked they are vulnurable to oxidation and to ambient yeasts and acetic acid bacteria (turns alc into vinegar)

Answer 20

all of these threats to quality, rises with higher temp
but black grapes are less vulnurable to oxidation because they contain more phenolic compounds that have anti oxidative properties

measures can be taken to minimise these threats:

• • harvesting grapes at night with lower temp or harvesting at rising sunlight if harvesting by hand
• • add of so2 at harvesting
• • reducing grape temp by putting them in cool storage room once received at the winery
• • sanitising harvesting equipments

Question 21

What are the steps at the face of grape reception ?

Answer 21

1) chilling (eventually
2) sorting
3) destemming
4) crushing

Question 22

On arrival from the harvested grapes to the winery, a number of options are possible:

Answer 22

it will depend on the volume, hand or machine, health and quality of the grapes

1) large volumes: a conveyor belt or screw belt (transportbanden) will be used, the former being gentler with higher quality potential

2) smaller volumes of handharvested grapes can be carried in manually or with a forklift
- - the grapes are conveyed either to the sorting phase or to the destemmer/crusher

Question 23

What are the chilling options ?

Answer 23

1) chilling of whole bunches usually takes place in a refrigeration unit
- - chilling takes time
* this can be benefical if the sorting tables and presses and other equipment are already in use

2) heat exchanger: if the grapes are in a more fluid form
- – can also heat in cool climate and cool in warme climate
- —– more present if machine harvested than the grapes are more fluid

• both of these options incur cost in terms of equipment and energy
  so where possible harvesting at night or in the early morning will keep the grapes cool and avoid these costs

Question 24

What are the factors depending sorting ?

Answer 24

1) ripeness and health of the fruit arriving at the winery
2) intended final wine and quality and price
3) any sorting already in vineyard
4) physical state of grapes (if grape arrives in big containers the grapes at the bottom will be crushed and released juice — this is too liquid to sort)

Question 25

The more sorting that is carried out, the higher the cost this is both due:

Answer 25

1) the labour requirement and time taken for meticulous (nauwkeurig) hand sorting and because greater scrutiny often result in lower yields -- the level of sorting need to be fit in the choise of expected sale of wine * in poor years and and in cool climates a greater of level of sorting may simply be required to remove mouldy and under ripe grapes * in good years grapes will be received in allmost perfect condition and less triage is needed (MOG often still needed) * grapes for inexpensive wines may not be sorted at all (cost, machinery or labour)

Question 26

what are the range of sorting options for quality wines ?

Answer 26

1) removing unwanted bunches or grapes before picking or during hand harvesting 2) sorting by hnd on a table or a moving or vibraion belt ( latter also removes mog) can take place before or after destemmin (sometimes both 3) optical sorting (high tech), uses digital imaging and software technology to scan individual grapes - - machine scans a 100 grape samples chosen by the grapegrower - - rejects grapes that not conform to the sample and the mog * this can be done in a harvesting machine or at receptionat the winery - -- grand cru estates bordeaux

Question 27

what can you tell me about destemming ?

Answer 27

1) Hand harvested grapes for most white and many red wines are destemmed on arrival at the winery 2) machine harvested grapes are already destemmed becuse the grapes are shaken from their stems during harvesting 3) destemmers generally work by a series of blades within a rotating drum that remove the grapes from the stems

Question 28

Why destemming ?

Answer 28

1) stems contains tannins, which can be extracted if the stems are left in contact with the wine - - these tannins are unwanted in white wines - -- are additional to skin/seed tannins in red wines * so can be desirable in some wines 2) if stems not ripe they can convey unwaned green flavours and bitter tannins to the wine

Question 29

Grapes are not destemmed for wines made in certain ways: ex:

Answer 29

1) red wine ferm that use some whole bunches (pinot noir burgundy or sonoma) 2) carbonic maceration (gamay beaujolais) 3) whole bunch pressing for some white wines (commonly for high quality sparkling wine)

Question 30

The crushing stage:

Answer 30

1) happens at the beginning of the winemaking process 2) it is the application of sufficient pressure to the grapes to break the skins and release the juice (making it available for ferm) -- it is not to be confused with pressing (which is the separation of the juice from the skins and seeds 3) it is important that the pressure applied is gentle enough not to crush the seed, shich would add bitterness * traditionally pressure was done by human feet 4) many wineries combines these two last processes with a combined destemmer- crusher machine - - using this machine means that sorting can only be done at the level of whole bunches

Question 31

What is must ?

Answer 31

1) the mixture of grape juice, pulp, skins, seeds that come from the crusher is commonly termed 'must' 2) for white wines, must may refer to the grape juice that is fermented - - pressing and clarification means pulp, skins and seeds have been removed 3) hence in winemaking must typically refers to the substance that is being fermented

Question 32

When pressing for white wines and when for red ?

Answer 32

1) white: the grapes are amost always pressed to extract the juice from the grapes and to separate the skins from the juice before ferm 2) red: before fermentation the grapes are crushed and pressed after the desired number of days on the skins or at the end of fermentation

Question 33

What can you tell me about the pneumatic press ?

Answer 33

1) most popular type of press throughout the world 2) also called air bag presses 3) made of a cylindrical cage with a bladder (blaas) that runs down the side or middle of it - - grapes are loaded into the tank (on one side of the bladder) - - the other side of the cage is filled up with air and as the bladder inflates, the grapes gradually pushed against grates on the side of the cage - ---separating the juice or wine from the skins 4) the advantages are that it can be programmed to exert (uitoefenen) different amounts of pressure (light pressure for less extraction, harder pressure for greater extraction - - which can provide different blending components if needed * it also can be flushed with inert gas before use to protect the juice or wine from oxidation

Question 34

What about the basket press ?

Answer 34

1) more traditional form of press(vertical press or champagne presses) 2) a basket is filled with grapes and pressure is applied from above 3) the juice or wine runs through gaps or holes in the side of the basket and is collected by a tray at the bottom of the press 4) a pipe transport the juice to another vessel 5) basket presses are not sealed vessels and therefore cannot be flushed with inert gases to avoid oxygen exposure - - some winemakers believe these are gentler than pneumatic 6) however these generally hold a smaller press load, are much more labour intensive and are therefore most suited to small wineries making premium wines

Question 35

Which other presses are used ?

Answer 35

1) horizontal screw press: - similar to basket press mounted horizontally abova a rectangular draining tray (rechthoekige) - -- less gentle than other presses and therefore less popular - - like pneumatic press requires batch processing: * a volume of grapes i loaded into the presses * they are pressed * skins are removed * press may be cleaned * next batch can be loaded - - takes a lot of time 2) continuous press allows grapes to be continually loaded into the press as it works by using a screw mechanism * this allows for quicker pressing of larger volumes of grapes * less gentle than pneumatic and basket - - well suited to producing high volumes of inexpensive wines

Question 36

most modern presses are computerised:

Answer 36

1) the winemaker can program the pressure and length of the press cycle to obtain the desired results 2) applying less pressure will extract less tannin and colour but will result in smaller volume of wine 3) a longer press cycle extends the contact between the skins and the juice/wine which extracts more aroma/flavour and tannin

Question 37

Winemakers can make a number of adjustments to the must. these can be made before, during or after the fermentation. what is legally permited depends from region to region. what kind of adjustments do you know ?

Answer 37

1) enrichment 2) Reducing alcohol 3) acidification 4) deacidification

Question 38

What is enrichment ?

Answer 38

1) common practice for winemakers in cooler climates to enrich the must either before or during fermentation do increase the alcoholic content to the final wine 2) generally enrichment in EU refers to a range of practices: * adding dry sugar * grape must * grape concentrate (RCGM): manufactured (vervaardigd) flavourless syrup from grapes * process of concentration: reverse osmosis, vacuum extraction, chilling - -- these also concentrate other parts in wine like tannins or if present, faults

Question 39

What is chaptalisation ?

Answer 39

1) adding dry sugar (named after Jean Antoine Chaptal 2) the source of the sugar can be beet or cane 3) in the eu this is allowed within limits in the cooler parts 4) in the warmer parts this is forbidden - - but they can add RCGM 5) Rising temp: less need for chaptalisation

Question 40

Examples of eu zones who permit chaptalisation:

Answer 40

zona A= Germany, excluding baden and UK: Min natural potential alc: 8% enrichment +3% -- max alc level in final wine if enriched 11,5(12 for red wines) zone Clllb: Most of Portugal, southern spain parts of southern italy and greece: Min natural potential alc: 9% enri: +1,5% -- max alc in final wine: 13;5%

Question 41

What is the potential alcohol ?

Answer 41

It is the amount of alcohol that would be created by fermenting all the naturally occurring sugar in the must into alcohol

Question 42

When adding sugar ?

Answer 42

When fermentation is underway because the yeasts are already active and can therefore cope better with the additional sugar in the must

Question 43

Sugar levels in musts can also be concentrated by technological means of removing water:

Answer 43

1) reverse osmosis 2) vacuum evaporation 3) cryoextraction: freezing the must or final wine and removing the ice from it - - first two are expensive due the initial outlay of the machines - - cryoextraction costs less and may be used more widely

Question 44

In warm or hot regions where sugar in the grapes can accumulate quickly, it may be desirable to lower the potential alcohol of the wine slightly by adding water to the grape must:

Answer 44

this is only permitted in a few countries * however adding water also dilutes the aromas, flavours and acids of the wine * other ways: removing alcohol

Question 45

In warm climates without any cooling influences the malic acids in the grape tends drops dramatically as the grapes ripen:

Answer 45

If not the wine can lack at freshness * it can also be used to lower the pH grade * routine in more warmer parts of the world

Question 46

Acidification is typically carried out by the add of tartaric acids, the acidic characteristics of the grapes other options are ?

Answer 46

1) Citric acid (not permitted in EU) 2) malic acid (less used as it could be turned into lactic acid by malo) 3) lactic acids (if it is still needed after malolactic ferm)

Question 47

Acidification can take place before, during or after the fermentation, however:

Answer 47

1) winemakers typically prefer to acidify before ferm starts, to benefit from the effects of a lower pH and because they believe that the acidity added at this stage integrates better within the profile of the wine as a whole

Question 48

EU acidification or deacidification:

Answer 48

Zone A: germany excluding baden and UK: -1 to 0g/l (tartaric acids) Zone Clllb: most of portugal southern spain parts of southern italy and greece: 0to +2,5g/l * * in the moderate climate CI, which includes Bordeaux, spains cool north and italys trentino alto adige - - winemakers may acidify or deacdify according to the season (-1 to + 2,5g/l) ** within the eu regions winemakers are not allowed both to chaptalize and to acidify musts, this is to prevent wines being stretched by the two additions

Question 49

In cool climates where grapes may have to be picked before theyre fully ripe it may be necessary to deacidify the must or wine. how ?

Answer 49

1) malolactic fermentation 2) adding calcium carbonate (chalk) or potassium carbonate - - lowers the acidity by the formation and precipitation of tartrates 3) high tech: ION exchane (investment and expensive machinery ** the deacidification needs to be in legal limits of the producers zone

Question 50

What is alcoholic fermentation ?

Answer 50

It is the conversion of sugar into ethanol (ethyl alcohol) and co2 carried out by yeast in the absence of oxygen (anaerobically) -- this conversion also produces heat, which has to be managed

Question 51

Yeast is a collective term given to the group of microscopic fungi that convert sugar into alcohol and affect the aroma/ flavour charcterisics of wines:

Answer 51

1) yeast needs oxygen to multiply quickly - - once any oxygen is used up by the yeast (in aerobic respiration) they switch to fermentation 2) The yeast species that are most often used in winemaking convert the sugars in the must to produce alcohol if given the right conditions: - a viable temp range - access to yeast nutrients (especially nitrogen - absence of oxygen

Question 52

As well as alcohol, co2 and heat the ferm process also produces:

Answer 52

1) volatile acidity (vinegar and nail polish remover smell) - in standard ferm not enough is produced to be perceptible 2) very small amounts of naturally produced so2 3) wine aromatics: * from aroma precursors: compounds that have no flavour in the must, but released by the action of yeast and create some aromas in wine. - -- ex thiols 4MMP give aromas of gooseberry and boxwood to SB - -- many terpenes (lianool and geranil which gives muscat its floral grapey aroma) * created by yeast: esters which gives many fruity aromas (banana flavours fro carbonic maceration - - the reaction of some species or strains may also produce detectable levels of undesirable reductive sulfur compounds (rotten eggs, rotten cabbage) and acetaldehyde (bruiced apple, paint thinner) 4) glycerol, which increases body to the wine

Question 53

What is Saccharomyces cerevisiae ?

Answer 53

1) Most common species of yeast used in winemaking 2) it can withstand well the high acidity, increasingly high alcohol of the must as it ferments - - it is fairly resistant to so2 in comparison to other yeast species - - it reliably ferments must to dryness 3) there are many strains within the species - - which give rise to the option to choose a strain (known as selection) for particular outcomes * ex: some will select a strain to boost the aromatics (mid price sb in Marlborough) * some will choose for ambient or cultured yeast that produce a more restrained fruit character (Sancerre) 4) other species are used for particular wines: saccharomyces bayanus: for must with high potential alcohol, or re fermenting sparkling wine

Question 54

What are ambient yeasts ?

Answer 54

1) also called wild yeasts: are present in the vineyard and winery 2) they will include a range of yeast species: Kloeckera and Candida - -- most of which will die if the alc rises above 5% 3) typically Saccharomyces cerevisiae quickly becomes the dominant yeast, even in wild fermentations

Question 55

What are the advantages of ambient yeast ?

Answer 55

1) Can add complexity resulting from the presence of a number of different species producing different aroma compounds 2) it costs nothing to use 3) The dominant yeast population in a must is unique to a place or region - - thus the yeast strain contribute to the individuality of wines or even the terroir of a wine 4) using ambient yeast may also be uses as a part of the marketing of the wine

Question 56

what are the disadvantages ?

Answer 56

1) ferm may start slowly: dangerous for the build up of unwanted volatile acidity and the growth of spoilage yeasts (such as brettanomyces) and bacteria, potentially leading to off flavours 2) ferm to dryness may take longer (not desirable i large volume wineries) - - also higher risk at stuck fermentation (ceases or slow) leaving the wine in a vulnurable state to spoilage organisms 3) consistent product can not be guaranteed, which can be a drawback - - especially for producers who are looking for consistency over many large vessels or across vintages

Question 57

what are cultured yeasts ?

Answer 57

1) also called selected yeast or commercial yeast 2) theyre strains that are selected in a laboratory and then grown in volumes suitable for sale 3) commercially available cultured yeast are often single strains of saccharomyces cerevisiae 4) to use: - must need to be cooled down to prevent ferm fwith ambient yeast and then the cultured yeast can be added - -- cultured yeast will overwelm the ambient yeast quickly - also you can add so2to supress ambient yeasts - -- a starter batch made of ferm must with cultured yeast is than added to the tank of must to be fermented

Question 58

What are the advantages of cultured yeast ?

Answer 58

1) produces reliable, fast fermentation to dryness 2) produces low levels of volatile acidity, given its speed and reliability, there is less danger from spoilage yeasts and bacteria - - many winemakers use cultured yeast to guarantee the security of a clean, completed ferment 3) also help to produce a consistent product from one vintage to another 4) there is a large selection of cultured yeast, so the winemaker can choose wisely to affect the style of wine: - - neutral yeast for sparkling wine base to enhancing the floral or fruity characteristics of aromatic varieties

Question 59

What are the disadvantages of cultured yeast ?

Answer 59

1) Some believe that it leads to siilarity of fruit expression (and hence the charge of industrial wine) 2) using cultured yeast adds the cost of using a commercial product

Question 60

yeast needs oxygen and yeast nutrients. Explain:

Answer 60

during the ferm itself does not require exposure to oxygen -- this is needed at the early stages to enable yeast to multiply rapidly at the beginning of fermentation Winemakers may also add yeast nutrients: - particularly nitrogen, because if levels are low the ferm can get stuck and rotten egg smells from undesirable sulfur compounds created by yeast that are stressed by the low nitrogen levels - --- also Diammonium phosphate (DAP) or thiamine (vitamine B1) can also be added as nutrient

Question 61

What about the temperature for the fermentation ?

Answer 61

The speed of ferm is related to the temperature of the must - - which in turn affects the style of wine being produced * winemakers may favour a relatively warm start of the ferm (25°c 77°f) and then monitor it regularly and cool or warm the must as required Above 35°c 95°f the ferm may slow down and stops as yeasts struggle to survive, which is a risk for stuck ferm --- hence the temperature must be controlled to prevent this from happening

Question 62

so What does cool ferm temp affects the winestyle ?

Answer 62

12-16°c 54-61°f: -- fresher, fruity white wines and rosé cool temp promote the production and retention of fruity aromas and flavours

Question 63

What does a mid range ferm temp affects the winestyle ?

Answer 63

17-25°C 63-77°f -- easy drinking fruity red wines to retain fruity aromas and low tannin extraction *middle of this temp range for less fruity white wines * top of this range for barrel ferm white wines (to reduce formation of fruity esters isoamyl acetate (banana flavour)

Question 64

Warm ferm temp also affects the winestyle:

Answer 64

26-32°c 79-90°f - - used for powerfull red wines * gives max extraction of colour and tann - - but can lead to a loss of fruity flavours

Question 65

what are the options for temperature control ?

Answer 65

1) temperature of the cellar (warmer rooms and cooler so the vessels can be transported if they need a change of temperature and if theyre fit to be tranported) 2) modern wineries have ferm controlled installed in many vessels - - they use water or glycol in jackets that surround the vessel (typically stainless steel) - - or in inserts that can be put into vessels - --- most are controled and monitored by comp 3) pumping over also releases heat

Question 66

What about stainless steel vessels ?

Answer 66

1) modern way: easy to clean, large range of styles and sizes and can control temperature of must and wine 2) neutral so protecting from oxygen 3) no adding flavours 4) modern high volume wineries due to price, hygiene and a very high level of mechanisation possible (aut pump over, temp control, aut emptying, etc) 5) they can require a substantial and initial financial investment

Question 67

Concrete vessels:

Answer 67

1) inexpensive option of the last century 2) high termal inertia: - - they maintain a more even temp control than stainless steel 3) small egg formed concrete vessels: - very expensive - - set up convection currents that mix the fermenting must and mix the lees during maturation

Question 68

Wood in fermentation:

Answer 68

1) retain heat well 2) care for hygiene because poors can carry bacteria and spoilage organisms 3) some prefer the small amount of oxygen 4) can reused for many times so inexpensive in a long term 5) white wines can be fermented in small barrels - - relatively rare for reds because they need to manage the cap

Question 69

what are the alternative options

Answer 69

1) plastic: light, versatile and usefull for small batch ferm - - is permeable to oxygen and can be difficult to control temp 2) terracotta

Question 70

what about malo ?

Answer 70

1) Lactic acid bact convert malic acid into lactic acis and co2 and produces heat 2) typically after ferm or during it

Question 71

What are the encouraging condtions for malo ?

Answer 71

1) 18-22°c 64- 72°f 2) mod ph 3) low so2 * historically it occurs naturally in spring * * now you can add cultured lactic acid bact

Question 72

What are the inhibiting conditions of malo ?

Answer 72

1) temp below 15°c low ph and mod so2 2) if not wanted winemaker can add enzyme lysozyme - - kills lactic acid bacteria - - or move batch of wine to another room to avoid spread of the bacteria - --- also can be filtered out

Question 73

Red wines go through malo naturally. it is an option for whites. what are the outcomes ?

Answer 73

1) reduction in acidity and rise in ph: - - lactic acid is weaker than malic - --- desirable for overly acidic wines (chardonnay cool climate) 2) some colour loss for reds 3) greater microbial stability: - - if wine already has undergone malo, it prevents the wine from malo in bottle if not wanted * however in cases where the ph of the wine is high, raising the ph makes the wine vulnurable to spoilage organisms and make wine not refreshing because the total acidity is decreased 4) modification of the flavour: - slight loss of fruit character and an add of butery notes (whites) - --- also increase volatil acidity

Question 74

Some winemakers choose to conduct malo in the same size of barrels for red and whit because:

Answer 74

they can manage the lees bi stiring them, enhancing and promote better integration of the flavours -- but more work because barrels can be at different temp so more monitoring * winemakers may to prefer to promote malo during ferm, this can increase fruity character and reduce production times saving money as wines can be finished and sold earlier

Question 75

What are the post fermentation adjustments ?

Answer 75

1) acidity or ph - - winemakers choose at this case for small interventions because it can unbalance a wine dramatically - --- this can be done at the same way as prefermentation 2) removal of alcohol: a. add water b. high tech: - reverse osmosis: cross flow filtration that removes a flavourless permeate of alc and water * this can be distilled and than blended back to recreate the wine * * costly - spinning cone: first extract the volatile aromas compounds from wine and then removes the alcohol * the flavour compounds are then blended back into the wine * * only financial viable in large volume winemaking 3) colour: reduce unwanted colour tints by fining the wine - - enhance colouring ageant MegaPurple (not everywhere permitted)