VINICULTUREPre-Fermentation


  • SUB-TOPICS Of VINICULTURE-PRE-FERMENTATION
    • What is Pre-Fermentation?
    • Stem Inclusion
    • Must
    • Punch-Down vs. Pump-Over

WHAT Is PRE-FERMENTATION?

**The Following Key Wine Analysis Listed Chronologically

DE-STEMMER- Machine That Separated and Removed Stems From Grape Clusters.

CRUSHER- Machine of Paddles and Rollers That Break Skins So Juice is Available to Yeast for Fermentation.

AUGER- Makes Loading and Feeding Your Grapes Into the Crusher-De-Stemmer Much Easier and Faster, Often Attached.

How the Grapes Are Handled: Roughly/ Delicately or In an Oxidative or Reductive Manner Has a Great Impact On How the Wine Will Come Out In the End.


STEM INCLUSION

To DE-STEM Or NOT To DE-STEM

VINICULTURAL DISCLAIMER~ There Terms Cluster/ Bunch/ Stems Are Interchangeable and Referred to by Peoples Preference.

  • THERE ARE The FERMENTATION OPTION WHEN REFERRING TO STEMS.
    • Whole Cluster Fermentation
    • Partial Cluster Fermentation
    • No Cluster Fermentation

Whole Cluster is a Wine Making Technique, and Stylistic Decision. There’s Usually No Recipe But Often Depends On Vineyard Site, Vintage and What Style Wine the Producer is Trying to Achieve.

STEM General Term For Material That Holds the Cluster Together. Stems Consist of 2%-4% of the Cluster Weight

  • Rachis– Main Axis of the Cluster, Bearing Flower Stalks at Short Intervals.
  • Pedicel– Attaches the Berries to the Rachis.
  • Peduncle– Bit That Attaches the Cluster to the Vine.

CLUSTER/ Bunch A Fertilized Inflorescence, Comprised of Many Berries.

  • Bunch/ Cluster Shapes– Conical/ Shouldered, Conical(Short), Conical(Long), Cylindrical, Cylindrical(Winged), Double Cluster.
  • Ways Bunches Differ-  Shape, Bunch Weight, Elongation
  • Proportion Rate– Percentage of Flowers That Received Pollen and is Now a Grape.
  • Clusters/ Bunch– Condition of Stems Plays an Important Roll, Are They Green or Lignified, is There Any Rot or Botrytis.
  • Lignification– Transition From Green Fleshy Plant to Woody Plant. Stems Begin as Green Photosynthetic Material, Then Undergo Lignification.
  • Having Stems In the Fermentation Can Lead to Different Outcomes Depending On the Degree of Lignification.
  • Whole Cluster Can Be From 10% to 100%.
  • Just as There Are Better Vintages and Vineyards Stems Can Be Different…Better Cleaner, Richer. Stem Should Be Assessed or Tasted On a Yearly by Vineyard or Oven by a Block by Block Basis.
  • Stems Can Be Assessed In the Mouth by an Educated Wine Maker or Vineyard Manager, Just as Grapes/ Seeds/ Skins Can Be Assessed.
  • Sometimes Grapes Are Destemed Completely, Then Stems Are Added Back by Percentage.

EFFECTS Of INCLUDING STEMS IN A FERMENTATION

  • VINICULTURE- ADVANTAGES– Added Complexity, Smooth Tannins, Balances Acid
    • Cap is More Aerated During Fermentation.
    • Fermentation Temperature Are Generally 2°-3° Degrees Cooler.
    • Adds Aromatic Lift, Structure, Body, Complexity, Spice, Texture, Absorbs Alcohol.(Which Lower Abv. Slightly)
    • Allow Yeast to Move Around Easier.
    • Stem Help Drain the Juice In a More Natural Way.
    • Cap is More Aerated, Allowing Yeast to More Around More Easily.
    • Whole Cluster Fermentation When Done Correctly/ or In Moderation Adds to a Wines Complexity.
    • Adds Spiciness and Light Herbal Notes.(Tea Cardamom, Nutmeg, Oregano, Bell Pepper)
  • VINICULTURE- CHALLENGES– Add Herbal or Green Character
    • Add Too Much Tannin to a Wine, If Not Lignified Stems Can Add Greenness.
    • Some Wine Makers Press Off Before Fermentation is Complete So There Isn’t a Long Contact With Stems and a Lot of the Bitter and Green Tannins Have Been Pulled Out.
    • Loss of Color, Stems Absorb Color by Leaching to the Color of the Wine.
  • HISTORY Whole Cluster Has Been Used For Millennium and is Considered Old Fashion and Rustic.
    • Often the Wine Maker Will Ferment is Batches and Blend Whole Cluster/ No Cluster Wines Together at the End In Percentages.
    • Clusters Are Comprised of Stems, Often Also Know as Rachis Plus the Pedicels Which is the Part That Attaches the Berries.
    • Stems Have Aromatic Compound That Don’t Exist Anywhere Else In the Grapes.
    • Whole Cluster Fermentation Shouldn’t Confused With Whole Berry Fermentation.

To CRUSH Or NOT To CRUSH

  • Crushed Berries    or       Partially Crushed Berries     or
  • Whole Berries **Refer to “CARBONIC MACERATION” For Detailed Information.

CRUSH & STEM/ DE-STEM COMBINATIONS

  • Crushed Berries  With  No Stems
  • Crushed Berries  With  Partial Stems
  • Crushed Berries  With  Whole Stems
  • Partially Crushed Berries  With  No Stems
  • Partially Crushed Berries  With  Partial Stems
  • Partially Crushed Berries  With  Whole Stems
  • Whole Berries  With  No Stems
  • Whole Berries  With  Partial Stems
  • Whole Berries  With  Whole Stems

Carbonic Maceration is the Most Extreme and Pure Version of Whole Cluster Fermentation.

CARBONIC MACERATION/ Maceration Traditionelle- Whole Bunch Fermentation Without the Presence of Oxygen In a Carbon Dioxide Environment.

  • Process That  Occurs When Intact Bunches of Grapes Are Fermented In a Sealed Vat That Has Been Filled With Carbon Dioxide.  Newly Picked Uncrushed Bunches Are Put In Closed Vats With Carbon Dioxide. Grapes On Bottom are Crushed by Weight as Fermentation Begins. Technique is Considered Reductive Wine Making.
  • Carbonic Maceration is an Intra-Cellular, Anaerobic, Enzymatic Metabolism Inside Each Berry and Produces Light Reds, Low Tannins (Minimizes Tannin Extraction), Intense Color, Fruity-Fresh Aromas. Carbon Dioxide is Trapped In Tank, and Grapes Bath In it. During This Process Some Alcohol is Produced (2% Abv.) Along With a Range of Other Compounds That Affects a Wines Aromas and Flavors.

SEMI-CARBONIC MACERATION- True Carbonic Maceration is Rare. In Most Cases Semi-Carbonic Maceration is Taking Place Where a Portion of the Crushed Grapes On the Bottom of the Vessel Are Going Through Regular Fermentation While Carbonic Maceration is Happening Concurrently.

  • VARIETAL ASSOCIATED WITH WHOLE CLUSTER FERMENTATION
    • Pinot Noir
    • Syrah
    • Gamay
  • CLASSIC CARBONIC MACERATION WINES
    • Beaujolais AOC.                  Chinon AOC.
    • Jumilla DO.                         Rioja DO.
    • Paarl DO

PRESS

GRAPE PRESS Machine Used to Extract Juice by Bursting Grape Without Crushing Skin. Different Presses Are Used When Seeking Different End Result. Pressure Must Be Controlled In Order to Avoid Crushing Seeds and Releasing Unwanted Tannins Into Juice or Wine.

  • White…Generally Pressed Before Fermentation.
  • Red…Generally Pressed After Fermentation.

TYPES OF GRAPE PRESSES

  • BASKET PRESS Large Basket Like Press With Pressure Applied by Large Plate That is Forced Downward On the Fruit by Screw or Hydraulic Device. Juice Flows Through Opening In Basket. (Traditional Basket Press Hasn’t Changed Much Over the Last 1,000 Years.)
  • HORIZONTAL SCREW PRESS- Horizontal Cylinder With Large Plates Attached On Each End. Plates are Screwed Together to Press Juice Through Openings.
  • BLADDER PRESS- Large Horizontal Cylinder, Closed On Both Ends After Grapes Are Pre-Loaded. Large “Bladder” Filled With Air and Pushed Against the Sides, Pressing Juice Through Openings of the Cylinder.
  • LAGAR- Stone Trough Used For Foot Treading of Grapes In Duoro Valley For Port Production
  • ROBOTIC PLUNGER AND TREADER- Low-Sided, Square, Stainless-Steel Tank (Similar Dimensions and Proportions to Traditional Stone Lagar. Four Rectangle Block or Feet Are Suspended From a Ceiling and Can Be Programmed to Move Across.

PRESS FRACTIONS/ CUTS

  • FREE RUN JUICE/ Pressurage-  Juice Drained Without Pressure From Freshly Pick Grape. (Gravity of the Bunches, Slightly Cracking Open)
    • Around the Core of the Grape is the “Intermediate Zone”, it Contains the Highest Quality Juice Which is High In Acid and Sugar and Come Out In the Form of Free-Run Juice.
      • Generally- 20%-50% of Juice is “Free Run”, This is Considered Superior, Contains Less Tannins and is Widely Sought After For High-End Wines.
      • 1st. Press- Juice That’s Pressed Out of Grapes.
      • 2nd. Press- Juice That Has Been Pressed Out of the Grapes With Force.
    • When You Get Pressed Juice Near the Skin You Get the Properties of the Skin. (Phenolic, Bitter Tannins, Astringent Acid)
    • Wine Press is Released After Each Press, Then Slowly Pressed Again.
    • Free Run Juice and Pressed Juice Often Blended Back Together to Desired Levels.
    • Free Run Juice is Used For…Sparkling Wine, Rose, Blanc de Noir.
  • LIGHT PRESS- General Term For the Press Fraction After the Free-Run Juice Has Been Collected.
  • MEDIUM PRESS- General Term For the Second Press Fraction.
  • HEAVY PRESS- General Term For Last Press Fraction.

These Press Fractions Are Done at Different Atmosphere of Pressure From .25 to 1.5 and Are Often Kept Separate and Blended Together Later.


MUST– Mass of Crushed Grape, Juice, Skin, Seeds, Stems, Pulp, Living and Dead Micro-Organisms.

  • MUST WEIGHT- Amount of Fermentable Sugars In Must.
  • POTENTIAL ALCOHOL- Alcohol Level That Could Be Achieved if Must is Fully Fermented, and if Wine Becomes Completely Dry. (Brix & Specific Gravity Are the Two Important Tools Used to Determine Potential Alcohol)
  • MACERATION- Period Juice is In Contact With Must Before Fermentation.
  • Cold Soak- Maceration Usually Done In Fermentation Tank Where Controlled “Cold” Temperature (48*-50*) to Keep Yeasts From Commencing the Fermentation Process. Cold Soak is Usually Done For 2-20 (and Beyond) Days With Sulfites to Knock Down Any Micro-Organisms or Bacteria That Might Have Come In From the Vineyard. After Cold Soak is Complete Tank is Heated to Desired Temperature Which Allow For Fermentation to Commence.
  • During Maceration Extraction of Phenolics Material of In Grapes (Tannins, Anthocyanins, Flavors Compounds, Colors) are Leached From Skin Into Must, the Future Aroma of the Wine are In the Skins of the Grapes
    RED= 2 to 20 Days…Enhances +BODY, Tannins, Color Development.

MACERATION vs. FERMENTATION Of WHITE GRAPES

  • Cold Soak Whites…Brings Aroma, Texture, Terpenes
  • Fermentation Whites…Brings Tannins Phenolics
  • Maceration…Hours vs. Days vs. Months vs. Years
    • Short Maceration- Anything Under 1 Day…Whites and Rose
    • Extended Maceration- Anything Over +30 Days….Barolo 40+Days
  • CUVAISON- Period of Time Juice is In Contact With Must During Both Maceration and Fermentation
    CAP/ MANTA- Mass of Solid Must Matter That Rises to the Surface of the Vat With the Escaping Co2 In the Form of a Layer During Cuvaison. Integration of the Cap Back Into the Fermenting Wine is Needed.
  • POMACE/ Marc- Mass of Pulp, Seeds, Stems, Skin Left Over After Pressing.
  • EXTENDED MACERATION- Wine is Left On Must After Fermentation is Completed, +Tannin Extraction, +Mouthfeel, +Color, +Complexity
  • EXTRACTION- Absorption of Phenolics and Other Compounds From Grape Solids. Extraction Can Take Place Before, During and/ or After the Fermentation Process.
  • EXTRACT- Non Volatile Substances That Give Wine Character (Minerals, Sugars, Pigments)
    -Determined by Evaporating Liquid In Wine and Weighing Residue

CHAPTALIZATION Process of Adding Sugar to Unfermented Grape Must In Order to Increase the Potential Alcohol Content After Fermentation.

  • Chaptalization Isn’t Intended to Make the Wine Sweeter, But Rather to Provide More Sugar For the Yeast to Ferment Into Alcohol.
  • Is an Vinification Advantage Used In Cool Climate Areas Which Have Difficulty Ripening Grapes.
  • French Governing Wine Body Has Been Setting Limits For Chaptalization Since Early 1900’s.
  • Cane Sugar, Corn Syrup, Beet Sugar Are Often Used.
  • PIONEERS~ ~Jean-Claude Chaptal~ “France” Chemist Who Developed Chaptalization.

PUNCH-DOWN vs. PUMP-OVER

PUNCH-DOWN/ Pigeage Done to Keep the Fermenting Wine and Skins Mixed Up During Maceraton/ Fermentation.  Done With Pole or by Hand to “Push Down” Manta/ Cap.

  • Punch-Down is a More Delicate Way of Stirring a Wine and Keeps Skins From Getting Too Extracted and Allows Little to No Amount of Added Oxygen In the Fermentation. This Process is More Popular With “Non-Interventionist” Winemakers.
  • Punch Downs Are Usually Done 1 to 3 Time Per Day Depending On How Much Extraction the Winemaker Wants In the Wine.
    • ADVANTAGES Preserves Aromatics
    • VARIETALS THAT SEE “PUNCH DOWNS
      • Pinot Noir

PUMP-OVER/ Remontage Fermenting Juice is Circulated or “Pumped-Over” the Cap Mechanically During Cuvaison.

  • This Extracts Higher Amounts of Tannin In a Wine Depending On Frequency and Force. “Pump-Over” Doesn’t Break Up the Cap but Keeps it Submerged.
    • ADVANTAGES  Gets Wine In More Contact With Yeast.
    • VARIETALS THAT SEE “PUMP OVERS
      • Zinfandel
  • AUTO-VINIFICATION- Machine Used to Draw Maximum Color and Extraction From Grape Must. Auto-Vinification is Non-Electric and Powered by a Natural Build-Up of Carbon Dioxide In Its System and is More Vigorous and Efficient Than Pump-Over. Carbon Dioxide is Given Off and Its Pressure Builds Up Inside the Tank and Forces the Juice Up an Escape Valve Which Spills Into an Open Tank On Top of the Vat Which Pushed Down the Cap.


**Refer to “BIBLIOGRAPHY/ Sources” For Details On Scholarly Works Referenced.