Ch 13 General Winemaking Options

Question 1

General winemaking options

What are the 8 overall general winemaking options?

Answer 1

○ O2 and S02
○ Transport to winery
○ Grape reception
○ Pressing
○ Must adjustments
○ Alc fermentation
○ MLC
○ Post-fermentation adjustments

Question 2

General winemaking options

What are oxidation reactions?

Answer 2

○ O2 doesn’t react with many compounds in must/wine -> those it does react with are oxidation reactions -> create many compounds that themselves react with many must and wine compounds
○ Timing and amount are key to det if they have pos or neg effect

Question 3

General winemaking options

How and why does oxidation impact fresh fruity white wines (4)?
Example?
What compounds can inhibit oxidation impact?

Answer 3

○ White wine needs protection from o2
○ Loss of fruitiness - many aroma compounds break down in presence of o2 -> Loss of fruitiness - e.g., thiols in SB
○ Unwanted aromas - acetaldehyde which forms from oxidation of ethanol -> nutty, apple aroma
○ Color impact - white wines can darken -> become gold and then brown
○ Phenolic compounds - have anti-oxi effect - can absorb more o2 before effects are perceived

Question 4

General winemaking options

What is protective winemaking and what is another name for it?

Answer 4

aka - reductive winemaking
Minimize O2 contact during winemaking process

Question 5

General winemaking options

What 5 steps can winemakers take to min O2 contact?

Answer 5

○ Avoid ullage in vessels - headspace of air bet wine and top of container -> fill to top; in non-airtight containers, may need to be topped up due to evaporation
○ Use of inert gases - chem inactive gases do not interact with wine - e.g., nitrogen, C02, argon -> flush out o2 from vessels, pipes and machinery; can also be used for headspace in vessels to prevent 02 contact
○ S02 - strong anti-oxi effects
○ Use impermeable containers - stainless, concrete, glass/screwcap during storage
○ Cool, constant temps - cool temps slow rate of oxi = why wine is matured in rel cool cellars/picking grapes early in morning so fruit not warm

Question 6

General winemaking options

When is controlled O2 exposure good for wine (3)?

Answer 6

○ Ferm - some o2 required to start ferm to promote growth of healthy yeast; lack of o2 can sometimes create reductive/off flavors
○ Hyperoxidation - for white wine, exposure of must to o2 can lead to greater o2 stability = increased aging potential
○ Color stability/tannins - for reds - o2 reacts with anthos and tannins to add color stability

Question 7

General Winemaking Options

What is hyperoxidation?
How is it done and why does it work?
What benefits?
What varieties best for?

Answer 7

• Exposure of must to O2 before fermentation
• Thought to make white wine greater O2 stability and increase aging potential
• Targets compounds in must that readily oxidize. Turns must brown, then compounds precipitate out during ferm.
• Best for netural varieties

Question 8

General winemaking options

How does O2 exposure impact wine over time?

Answer 8

○ Changes aromas/flavors = greater range and diversity
○ Fresh fruits -> dried fruits
○ Tertiary notes of caramel, honey, nuts, coffee, leather, mushroom

Question 9

General winemaking options

What wines need high level of O2 exposure?

Answer 9

Oxidative styles - Oloroso sherry, madeira, tawny port

Question 10

General winemaking options

How can O2 exposure be increased?

Answer 10

○ Cap management techniques in red wine ferm
○ Use of small wood barrels -> small vol wine rel to amt o2 that enters thru bung and staves
○ Inc number of rackings and/or amt of lees stirring during aging -> any procedures that req bung/lid opened and/or wine moved = more o2 exposure
○ Allow ullage
○ Techniques that pump o2 into must (hyperoxi) - or the wine (micro-oxi)

Question 11

General winemaking options

How does O2 relate to spoilage?

Answer 11

○ Presence of 02 can favor growth of spoilage orgs -> acetic acid bacteria, brett if conditions are favorable (e.g., sugar present)
○ Wines exposed to o2 must be carefully monitored

Question 12

General winemaking options

What properties does SO2 have?

Answer 12

○ It is a preservative
○ Anti-oxidant - only reacts w/ O2 itself very slowly -> reduces oxi effects by reacting with products of oxi reactions so they can’t further oxidize compounds in wine; inhibits oxidative enzymes
○ Anti-microbial - inhibits development of microbes like yeast and bacteria; diff species of yeast vary in sensitivity to S02

Question 13

General winemaking options

How can SO2 be added?

Answer 13

○ Gas, liquid, solid
○ As S02, potassium metabisulfate, potassium bisulfate
○ Small amt <10mg/L produced naturally in ferm

Question 14

General winemaking options

How are SO2 levels regulated
How handled in organic viticulture?
What are labeling requirements?

Answer 14

○ Max concentrations defined by local laws since it is toxic
○ EU - max in reds is 150mg/L and whites is 200mg/L; sweet can have higher levels
○ Organic wine limits lower than non-organic; natural winemakers can choose not to add any or only very small amt
○ Levels in wine are below toxic level, though some people have allergic reaction
○ If wine has >10mg/L - “contains sulfites” must be on label

Question 15

General winemaking options

When is SO2 added?
What happens when it is (2 kinds of S02 in wine)?

Answer 15

○ Usually added soon after grapes picked/reach winery; can be added at various other points in winemaking process - usually at bottling
○ Some becomes bound S02 - when added to must or wine -> dissolves and some of it reacts with compounds in the liquid and becomes bound -> bound S02 NOT effective as anti-oxi or anti-microbial
○ Free S02 - S02 not bound to other compounds. Most free SO2 exists as rel inactive form and small prop exists as molecular S02 which is most effective vs oxi and microbes

Question 16

General winemaking options

What is relationship of pH to SO2?

Answer 16

○ pH level in must or wine has key effect on efficacy of S02
○ Greater amt of free S02 is in molecular form at LOWER pH levels (more acidic) -> more S02 needs to be added to must/wine that have rel higher pH (less acidic) to protect them

Question 17

General winemaking options

What role do timing and amount of SO2 play?
What can winemakers do to limit amount needed?

Answer 17

○ Adding larger amt when grapes are crushed, at end of MLC and at bottling are considered more effective than adding small amts throughout winemaking process
○ Careful winemakers try to limit S02 additions both because of legal limits and because it can dull flav/aromas and sometimes cause wine to taste harsh
○ Winemakers can ensure good hygiene and effective grape sorting to limit microbes in winery; limit o2 exposure and keeping grapes/must cool reduces amt s02 needed for anti-oxi/microbial

Question 18

General winemaking options

What are the risks during transportation of grapes to winery?

Answer 18

○ Grapes vulnerable to oxidation as well as ambient yeasts and acetic acid bacteria
○ Threats greater at higher temps
○ Black grapes less vulnerable - have more phenolic compounds that have anti-oxi properties

Question 19

General winemaking options

What can winemakers do during grape transport to reduce risk of O2/microbe exposure?

Answer 19

○ Harvest/transport at night when temps cooler (or at sunrise if hand harvesting)
○ Add S02 at time of harvest
○ Cool grape temps by putting in cold storage room on reception
○ Sanitize harvesting equipment/bins (only prevents microbes)
○ Collect/transport grapes in small crates - minimizes crushing

Question 20

General winemaking options

What are harvesting considerations for hand harvested vs machine harvested grapes?

Answer 20

Hand harvest
* Usually put in small, stackable crates that pickers can carry - minimal crushing = less o2 and microbe exposure
* Small crates tipped into larger hoppers for transport - can cause some crushing -> some growers add S02 in form of potassium metabisulfate

Machine harvest
* Fruit has already been de-stemmed by picking and is usually transported in large containers = some juice released
* Can add s02 at this point - some newer machines can sort/crush and add s02 before transport to winery

Question 21

General winemaking options

What are 4 main processes in grape reception?

Answer 21

○ Chilling
○ Sorting
○ De-stemming
○ Crushing

Question 22

General winemaking options

What are the factors affecting how grapes are handled at reception?
How are large vs small volumes handled?

Answer 22

Factors:
○ Amount of grapes
○ Whether hand or machine harvested
○ Health/quality of the grapes

	○ Large - conveyor belt or screw conveyor (more gentle)
	○ Small - moved manually

Question 23

General winemaking options

What is chilling phase?
What method options are used and why?
What are some considerations for different approaches?

Answer 23

○ warm grapes inc rate of oxi -> chilling helps preserve fruity aromas and reduce spoilage risk
○ Whole bunches - usually in refrigeration unit -> chilling whole bunches takes time which can slow processing of grapes
○ Heat exchanger - can be used to chill if grapes are more liquid format (machine harvested, destemmed and maybe crushed) = works very quickly
○ Costs - both have equipment and energy costs -> harvest at night/early morning to avoid costs

Question 24

General winemaking options

What factors determine how sorting is done?

Answer 24

○ Ripeness and health of fruit
○ Final intended quality and price
○ Whether any sorting was done in vineyard
○ State of grapes - if some have been crushed, may be too liquid to sort

Question 25

General winemaking options

How does QSP affect sorting decisions?

Answer 25

○ Amount and level of sorting needs to be considered relative to expected return
○ More sorting = higher cost due to labor and time -> greater scrutiny often means lower yield
○ Poor years/cool climate - more sorting may be req to remove moldy/under-ripe fruit
○ Good years - sorting may only need to remove MOG
○ Inexpensive wines - may not be sorted at all

Question 26

General winemaking options

What are sorting options for premium wines?

Answer 26

○ Remove unwanted grapes/bunches before picking/during hand harvesting
○ Sort by hand on a table or vibrating belt (also removes MOG); can be before or after de-stemming
○ Optical sorting

Question 27

General winemaking options

What is optical sorting?
What kind of wine done for?

Answer 27

§ high tech, high cost option using digital imaging and software to scan individual grapes
§ Scan 100 grape sample, then full load passed thru and it rejects ind grapes (and MOG) that don’t meet sample
§ Can be done in harvesting machine or at reception
§ Usually only done for premium/super-premium due to cost

Question 28

General winemaking options

What is de-stemming?
When is it done, how and why?

Answer 28

○ Hand harvested grapes for whites and most reds are destemmed on arrival
○ Machine harvested - destemmed in vineyard already because grapes are shaken off vine
§ Work by means of series of blades within a rotating drum that removes grapes from stems
○ Stems contain tannin which can be extracted if left in contact with wine -> not wanted in whites and are additional to seeds/skins in reds
○ If stems not ripe, can add unwanted green flavors and bitter tannins

Question 29

General winemaking options

What wine styles are not de-stemmed?

Answer 29

○ Whole bunch ferms for reds (Burg PN)
○ Carbonic
○ Whole bunch pressing for some whites - common in high quality sparkling

Question 30

General winemaking options

What is crushing?
How is it different than pressing?
How is it done and what are key considerations?

Answer 30

○ Happens at beginning of winemaking process
○ It is application of enough pressure to break grape skins and release juice making it avail for ferm
○ Different than pressing - separation of juice or wine from skin/seeds
○ Pressure gentle enough to not crush seeds -> would add bitterness
○ Traditionally done by feet, now most wineries have a combined de-stemmer/crusher -> using this means sorting can only be done at whole bunch level

Question 31

General winemaking options

What is must?

Answer 31

○ The substance that is being fermented - the mixture of grape juice, pulp, skins and seeds that comes out of the crusher
○ For whites - can also be the grape juice that is fermented (after pressing and clarification - pulp, seeds and skins removed)

Question 32

General winemaking options

What is the difference in the pressing process for whites vs reds?

Answer 32

○ Whites - grapes almost always pressed to extract juice AND separate skins from juice BEFORE ferm
○ Reds - grapes usually crushed before ferm and pressed AFTER desired time on skins or at end of ferm

Question 33

General winemaking options

What is soft pressing and why important for whites vs reds?

Answer 33

○ Whites - goal is to crush and press berries to max juice release without extracting tannins from skins/seeds and avoid too many solids
○ Reds - since pressing is usually after ferm, need to take care to not extract excessive tannin/bitterness from skins and seeds that have been softened by being in must for 5 days - 3 weeks

Question 34

General winemaking options

What are the 4 kinds of presses?
Which ones require batch processing?

Answer 34

○ Pneumatic
○ Basket
○ Screw
○ Continuous

	Batch processing - pneumatic, basket and screw

Question 35

General winemaking options

What are pneumatic presses, how do they work, adv/disadv, where most commonly used?
What is another name for them?

Answer 35

○ Most popular type of press - aka air bag presses
○ Has cylindrical cage w/ a bladder that runs down side or middle of it
○ Grapes loaded into tank on one side of bladder, other side of tank filled with air inflating bladder -> grapes gently pressed against grates on side of cage separating juice from skins
○ Adv - can be programmed with diff amts of pressure, can be flushed w/ inert gas before use to protect juice/wine from oxi
○ Disadv - expensive - most common in mid to large scale wineries, batch processing req

Question 36

General winemaking options

What are basket presses, how do they work, adv/disadv, where most commonly used?
What is another name for them?

Answer 36

○ More traditional form of press but still in use
○ Aka vertical presses/champagne presses
○ Basket is filled with grapes -> pressure applied from above -> juice runs thru holes in side of basket and collected at bottom of press. Pipe transfers juice/wine to another vessel
○ Adv - some winemakers feel these are gentler than pneumatic,
○ Disadv - not sealed, so can’t be flushed with inert gas to min 02 exposure, hold smaller volume than pneumatic -> much more labor intensive, batch processing req
○ Most common to small wineries making premium wines

Question 37

General winemaking options

What are horizontal screw presses, how do they work, adv/disadv, where most commonly used?

Answer 37

○ Similar to basket press - mounted horizontally above rectangular draining tray
○ Less gentle, so less common
○ batch processing req

Question 38

General winemaking options

What are tradeoffs of using computerized press?

Answer 38

○ Adv - can be precisely programmed - amt of pressure and length of cycle
○ Disadv - less pressure = less color/tannin extracted but also less volume of juice/wine

Question 39

General winemaking options

What are continuous presses, how do they work, adv/disadv, where most commonly used?

Answer 39

○ Allows grapes to be continually loaded into press as it works by using screw mechanism
○ Adv - faster pressing of large volumes of grapes
○ Disadv - less gentle
○ Best for high vol, inexpensive wines

Question 40

General winemaking options

What are tradeoffs between quality/volume in terms of pressure and press time?

Answer 40

○ Seek balance between quality of juice/wine and volume that can be made
○ Longer press cycle extends contact between skins and juice/wine which extracts more flavor and tannin

Question 41

General winemaking options

What is pomace?

Answer 41

Solid remains of skins and seeds after pressing

Question 42

General winemaking options

What is the goal of adjusting the must and when are they usually done?
What are the 5 main must adjustments?

Answer 42

○ Create more balanced wine-> especially if there’s been a compromise in reaching optimal ripeness of sugar/acid/tannin/flavors

Done after must clarification for whites, can also be done after fermentation

5 adjustments:
Alcohol related
1. Enrichment/chaptalization
2. reduce alcohol

Acid Related
3. acidification
4. de-acidifcation

5. add tannins

Question 43

General winemaking options

What are 4 factors that can influence whether to do pre-ferm adjustments?

Answer 43

1. climate type
2. bad weather that year
3. pests/disease
4. style of wine desired

Question 44

General winemaking options

What is enrichment, when is it done?
What does it mean in the EU in terms of 2 ways it can be done and the specific techniques for each?
What is process of adding sugar known as?

Answer 44

What is it and when done:
○ In cool climates, common to enrich must with sugar to increase alc content of final wine
○ Done either before or during ferm

In EU - increase sugar by
1. addition - dry sugar, grape must, grape concentrate or RCGM
2. concentration - reverse osmosis, vacuum extraction, chilling

Adding sugar - enrichment or chaptalization

Question 45

General winemaking options

What is RCGM

Answer 45

Rectified concentrated grape must
- manufactured flavorless syrup from grapes

Question 46

General winemaking options

What kind of sugar is allowed?
In EU how does this vary from cool to warm climate zones?
How does EU structure its regulation - examples and levels?

Answer 46

○ Sugar can be beet or cane
○ In EU, allowed with limits in cooler areas;
○ in warmer areas, not allowed to add sugar except for grape concentrate or RCGM within limits
○ As temps rise, may be less need for enrichment

	EU regulation:
			○ Split into zones that determine the level of enrichment allowed - as well as acidification/de-acidification
	○ Ex - Zone A (coolest) Germany - min natural alc -8%; max enrichment +3%; max final alc if enriched 11.5% (12% reds)
	○ Ex Zone CIIIb (warmest) Portugal, S Spain, etc. - min natural alc 9%; max enrich +1.5%; max final alc if enriched -13.5%

Question 47

General winemaking options

What is potential alcohol?

Answer 47

Amt of alc created by yeast ferm all natrually-occurring sugar in the must into alc

Question 48

General winemaking options

When is enrichment allowed to be done and when is it actually done in “real world” practice?

Answer 48

Allowed to be done either before or during fermentation

○ In practice, done when ferm is underway -> yeasts are already active and can better cope with add’l sugar

Question 49

General winemaking options

What technologies can be used for enrichment, how do they work and what are considerations?

Answer 49

○ Reverse osmosis and vacuum extraction - most expensive due to machinery cost -> limit use to wines where can recoup ROI or high volume wines
○ Cryoextraction - freezing the must or even final wine and extracting ice from it - costs less and is more widely used

In all cases, need to consider economics given there will be less wine at the end

Question 50

General winemaking options

What is the goal of alc reduction and how is it done?
Where is it allowed?
What are disadvantages?
When/how else can it be done?

Answer 50

○ Reduce potential alc in warmer areas (sugar can accum quickly in grapes)
○ Add water to must to reduce alc level slightly
○ Only legal in some areas - in CA - water can be used within the addition of other processing additives
○ Disadv - dilutes grapes aromas, flavors and acids
○ Can also be done by removing alc from final wine in post-ferm adjustment

Question 51

General winemaking options

What is acidification?
What kinds of regions is it done in?
Why do it, what benefits/impacts on wine?
and how do it?

Answer 51

○ Increase acidity of must in warmer areas without cooling infl -> grapes lose malic acid signif as grapes ripen; if wine not acidified can lack freshness
○ Also done to lower pH -> inc microbiological stability, inc effectiveness of S02, inc red color in red wine and enhances ability of wine to age
○ Done in most warmer areas for inexp and mid-price wines and many premium

	○ Usually done by adding tartaric acid; can also add
	      ○ Citric acid -> not allowed in EU for acidification
	      ○ Malic acid -> less used as it can be turned into lactic acid by MLC
	      ○ Lactic acid -> can be used if adjustments are made after MLC -
				   tastes less harsh than other acids

Question 52

General winemaking options

When in winemaking process is acidification done?
How does EU regulate?

Answer 52

○ Can be done before, during or after ferm
○ Most winemakers prefer before ferm starts to benefit from effects of lower pH and because its believed acid added at this point is better integrated into wine
○ Total acidity and pH can both be affected during other parts of winemaking process - MLC, tartrate stabilization -> winemaker needs to consider this in det how much to add

EU Regulation:
○ Same as enrichment - by climatic zone
○ In coolest areas - only de-acidification is allowed
○ Moderate zone CI - Bordeaux, N Spain, Trentino-Alto Adige: can deacidify or acidify
○ In warmest zones - acidification is allowed
○ Winemakers not allowed to BOTH chaptalize and acidify - to prevent musts from being “stretched” by the additions

Question 53

General winemaking options

Why is de-acidifcation done and under what circumstances?
What needs to be considered?
How is it done?

Answer 53

○ Cool climates - grapes may be picked before fully ripe = need to de-acidify must/wine
○ Consideration - need to think about final acid level taking into account lowering of acidity due to MLC
○ Add calcium carbonate (chalk) or potassium carbonate - lowers acidity by formation and precipitation of tartrates
○ Ion exchange - high tech option - signif equip expense and need to ensure legal where the wine is sold
○ EU law sets limits on de-acidification

Question 54

General winemaking options

How are tannins adjusted, why and when in process?

Answer 54

○ Add powdered tannins
○ Helps clarify must, and for reds also stabilizes color of must and improves mouthfeel
○ Can be added to the must before ferm or to the wine before mat

Question 55

General winemaking options

What is alcoholic ferm?
What is the alcoholic ferm equation?

Answer 55

○ Conversion of sugars to ethanol and CO2 by yeast in the absence of O2 (anaerobically). Also releases heat which needs to be managed

	○ Sugar + yeast + O2 = ethanol + CO2 + heat

Question 56

General winemaking options

meta Q for test prep:
what are the key topics to remember related to fermentation?

Answer 56

yeast types - ambient vs cultured
yeast impact
what fermentation process produces besides alc, CO2 and heat
fermentation temperatures - temp ranges
ferm vessels

Question 57

General winemaking options

What are yeast and what impact do they have on wine?
How do yeast do their work?
What is aerobic respiration vs fermentation?
What are optimal conditions for yeast to conduct ferm?

Answer 57

What are yeast/imapct on wine:
○ Microscopic fungi that convert sugar to alc
○ Affect the flavors/aromas of wine

Aerobic respiration vs ferm:
○ Initially, yeast need o2 to multiply = aerobic respiration
○ Use up 02 and they switch to fermentation

Optimal conditions:
○ Viable temp range
○ Access to yeast nutrients - esp nitrogen
○ Absence of oxygen

Question 58

General winemaking options

What are examples of wine aromatics that form from aroma pre-cursors during ferm?
What are examples of wine aromas created by yeast directly during ferm?

Answer 58

Pre-cursors: - have no flavor/aroma in must - activated by yeast
○ Thiols - 4MMP - boxwood/gooseberry in SB
○ Terpenes - linalool and geraniol - floral/grapey aromas in Muscat

By yeast directly:
○ Esters - fruity aromas/flavors - banana in carbonic wines
○ Undesirable aromas - some yeast strains create reductive sulfur compounds (rotten egg/cabbage) and acetaldehyde (bruised apple/paint thinner)

Question 59

General winemaking options

What else does fermentation produce (4) beyond creating alc, CO2 and heat

Answer 59

○ Volatile acidity - in normal ferm, not enough to be perceived
○ Very small amts of naturally occurring SO2
○ Wine aromatics - from aroma precursors or created by yeast
○ Glycerol - increases body of wine

Question 60

General winemaking options

What is most common yeast species and why?

Answer 60

○ Saccharomyces cerevisiae
○ Reliably ferments to dryness -> it can withstand high acidity and inc alc levels of must as it ferments
○ Also resistant to S02

Question 61

General winemaking options

When is O2 needed in ferm process?
What can winemakers do to help yeast?

Answer 61

○ O2 needed at start of ferm process to enable yeast to multiply rapidly
○ Can add yeast nutrients - esp N if levels in must are low
○ Low N -> stress the yeast and cause them to create reductive sulfur compounds (rotten egg) and/or to stop fermenting
○ DAP (Diammonium phosphate) or thiamine (B1) can be added as nutrients

Question 62

General winemaking options

Where is ambient yeast found, aka, examples and how related to Sacch?
What are adv?
What are disadv?

Answer 62

○ Found in vineyard and in the winery
○ Includes range of yeast species - ex Kloeckera and Candida
○ Most ambients die when alc above 5% ->
○ Sacch becomes predom even in wild ferms
○ SO2 favros sacch (kills ambient)
○ ambient prefer cooler temps vs sacch

advantages
○ Can add complexity to wine from several species being present, producing different aroma compounds
○ Free
○ Yeast pop in a must can be unique to place/region esp if cultured yeasts not been used
○ Can be used in marketing the wine

disadvantages
○ Ferm may start slowly - dangerous for buildup of unwanted VA and growth of spoilage orgs (brett) and bacteria which can lead to off flavors
○ Ferm to dryness can take longer - may not be desirable in high vol winery
○ Risk of stuck ferm leaving wine vulnerable to spoilage orgs
○ Cant guarantee consistent product

Question 63

General winemaking options

What is cultured yeast, aka?
How is it used?
What is another strain of cultured yeast and what used for?
Advantages and disadvantages?

Answer 63

• Yeast strain selected in lab and grown in volumes to sell -> often single strain of sacch
• Aka selected yeast or commercial yeast

How used:
○ Must may be cooled to prevent ferm from ambient yeast; or SO2 can be added
○ Starter batch made up of fermenting grape must which has been activated with cultured yeast then added to tank of must to be fermented
○ Cultured yeast that are added which quickly overwhelm natural yeast

Another strain:
○ Sacch bayanus - used for must w/ high pot alc or re-ferm sparkling wine

Advantages:
○ Reliable, fast ferm to dryness
○ Produce low levels of VA
○ Given speed/reliability - less risk of spoilage orgs/bacteria -> one of main reasons winemakers use cultured yeast
○ Consistent product across vintages
○ Large selection of cultured yeasts available -> can tailor to quality/style (neutral for sw; another to boost aromatics of SB)

Disadv:
○ Some feel lead to similarity of fruit expression (industrial wine)
○ Adds cost

Question 64

General winemaking options

How is ferm temp related to ferm speed?
How do winemakers use ferm temp across ferm cycle?

Answer 64

○ Temp related to speed of ferm and affects style of wine being made
○ Many winemakers prefer warmer (25°C) temp at beginning to get yeast estab and then adjust must temp up or down as needed

Question 65

General winemaking options

What are temp ranges that define key white and red styles and why?
What is considered a high ferm temp and what happens?

Answer 65

○ Cool 12-16°C - fresher, fruitier white wines and rose -> promote production and retention of esters

	○ Mid-range 17-25°C
		   § Reds - easy drinking fruity red wines to retain fruit aromas and for low tannin extraction
		   § Whites - middle of range for less fruity whites; top of range for barrel ferm whites
			 
	○ Warm 26-32°C
	  	§ Reds - for reds with pronounced flavor concentration and high tannins -> max extraction of color and tannins,  but can lose some fruity flavors

High = 35°C
- ferm can slow/stop as yeast can’t survive -> temp needs to be controlled

Question 66

General winemaking options

What are the ways to control ferm temps?

Answer 66

○ Most basic level (traditional) - ferm temp can be affected by cellar temp and adjusted by changing that temp. Sluggish ferms can move to warmer room and over-warm to cooler areas
○ Modern wineries have ferm temp control systems - water or glycol jackets on ferm vessels (or inserts)
○ Pumping over (délestage) can release also release heat

Question 67

General winemaking options

What are the 3 main types of ferm vessels?

Answer 67

○ Stainless steel
○ Concrete
○ Wood

Question 68

General winemaking options

What is ‘modern standard’ ferm vessel type?
What are adv and disadv?

Answer 68

Stainless Steel
○ Modern standard - easy to clean, avail in large range of sizes, gives high degree of temp control
○ Neutral vessels - no flavor/aroma imparted
○ Very good at protecting from O2
○ Most common in modern, high vol wineries due to price, hygiene and high deg of mechanization

Disadv
- substantial initial cost

Question 69

General winemaking options

Concrete vessels - what are the key characteristics and considerations

Answer 69

○ Adv - high thermal inertia - maint even temp more efficiently than s/s
○ Smaller vessels are very expensive, but thought to set up convection currents that mix fermenting must and mix the lees during mat (natural lees stirring)

Question 70

General winemaking options

Wood ferm vessels - what are adv/disadv?

Answer 70

Adv
○ Retains heat well
○ Allows micro-oxygenation that benefits red wine ferm in oak
○ Can be re-used many times - lower long term cost
Disadv
○ Hygiene care is key - pores in wood can harbor bacteria/spoilage orgs
○ Very expensive to purchase initially

Question 71

General winemaking options

What are other/secondary ferm vessel options, what used for and key considerations?

Answer 71

○ Plastic - light, versatile and good for small batch ferm; but permeable to O2 and temp hard to control

	○ Terracotta - used historically and in small scale today - amphorae, qvevri

Question 72

General winemaking options

What is MLC?
What is another name for it?
What happens and when in process is it done?
How does it happen?

Answer 72

○ Aka MLF, Malo
○ Result of lactic acid bacteria converting malic acid into lactic acid and CO2 + heat (like another form of ferm)
○ Usually happens after alc ferm and sometimes during it

How happen:
○ Historically - spontaneous in spring
○ Now - can be started by adding cultured lactic acid bacteria and when optimal conditions are available

Question 73

General winemaking options

What conditions are needed for MLC?

Answer 73

○ Temp - 18-22°C
○ Moderate pH level - 3.3-3.5
○ Low TOTAL SO2

Question 74

General winemaking options

What conditions prevent MLC?
What can winemakers do?

Answer 74

Conditions to prevent:
○ Temp <15°C
○ Low pH (acidic environment)
○ Moderate levels of SO2

Winemakers can
§ add enzyme lysozyme -> kills lactic acid bacteria
§ move any batch of wine undergoing MLC to another part of winery to avoid spread of lactic bacteria
§ Filter out lactic acid bacteria to completely prevent

Question 75

General winemaking options

How are reds/whites different with regard to MLC?

Answer 75

Reds regularly go thru it
Whites - winemaker choice

Question 76

General winemaking options

What are outcomes of MLC and why?

Answer 76

○ Reduction in acidity and rise in pH -> lactic acid weaker than malic; may be desirable in overly acidic wines -> results in softer/smoother wine
○ Some color loss in reds - only an issue in very pale red wines
○ Greater microbial stability -> if goes thru MLC during or after alc ferm, prevents MLC from happening later spontaneously which is undesirable
§ If pH of wine is high, raising pH slightly can make wine more vulnerable to spoilage orgs
○ Modifies flavor - slight loss of fruit flavor, addition of buttery notes (diacetyl); increases VA

Question 77

General winemaking options

Why do some winemakers do MLC in barrels vs tank, considerations?
Why do some winemakers do MLC at same time as alc ferm?

Answer 77

Barrel vs tank:
○ Ability to stir lees at the same time and better integrate flavors
○ Adds work - barrels may be at different temps and so need to monitor individually

Same time as alc ferm:
- Inc fruity char and shortens production times -> saves money as wines can be finished and sold sooner

Question 78

General winemaking options

What are the 3 main post-ferm adjustment options?

Answer 78

○ Acidity, pH and tannins can be adjusted in same ways as before ferm; winemaker should only make small adjustment post-ferm -> maintain balance of wine
○ Removal of alc
○ **Color **- reduce unwanted tints

Question 79

General winemaking options

Why is alc removal done post-ferm?
How is it done (low and high tech)?

Answer 79

Why done:
* Make a lower alc wine (<5.5%) or adjust alc level slightly

How:
○ Easiest to add water to must - but also dilutes flavor
○ High tech solutions:
§ Reverse osmosis - most common - form of cross-flow filtration that removes flavorless permeate of alc and water which can be distilled to remove alc, then blend back in ->equipment costly but can be rented
§ Spinning cone - device first extracts volatile aroma compounds and then removes alc; aroma compounds then blended back in to wine of desired alc level -> only economic for large vol producers
§ EU allows both high tech approaches, but within limits

Question 80

General winemaking options

What is post ferm color adjustment?
How is it done?
Laws example?

Answer 80

○ Remove unwanted tints by fining the wine
○ When making high vol wine, can enhance color by adding very small amts of MegaPurple - grape-derived coloring agent
○ Regulated in some areas - not allowed in Ribera del Duero