Pre Fermentation Processing - Wine - Lecture Slides, Slides of Winemaking

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Pre-Fermentation Processing

Pre- 1°^ 2°^ Aging^ Wine Stabilization^ Bottling GrapeMaturity Ferm

Harvest (pH, TA, Brix, MOG)^ Yeast Inoculation MLB Inoculation^ Add Molecular SO

2

Sugar Decline Malic Decline VA and FSO

2 Big-3^ DO

Master Blend Completed Stabilization Complete

TIME

Clean Winemaking Stage Diagram

Grape Notes

Following veraison

Grape Maturity Monotoring

Stage

QC

Milestones

Gates Stylistic^ TempNutrients RS-Enz Mal-Enz (^) Stylistic Stable

Bottled Wine

SO2/BP

Time (Not to Scale)

Pre-Fermentation

• Harvest marks the beginning of Pre-

Fermentation

• Inoculation with wine yeast marks end of the

Pre-Fermentation stage

Pre-Fermentation

• All of the processes involved with bringing the

fruit in from the vineyard and manipulating

the clusters and berries into the desired state

• Pull juice samples for sugar, acid and Nitrogen

content

• NOTE – Chemical analysis are generally pulled

to measure chemistry that, if uncorrected, my

cause significant quality or winestyle defects.

Harvest

• Harvest grapes near the temperature you want to

process at

• Sample grapes near the expected picking time
• Minimize shearing of grapes before their arrival to

the winery

• Off-load and weigh grapes
• Grade grapes (MOG, visual assessment, analyses)
• Begin processing as soon as possible

Small Winery Receiving Equipment

Pallet Scale

Grape Processing

Small Winery Receiving Example

Hopper

To destemmer /crusher

Shaker Table

Progressive cavity or Must Pump

Screw Pump

Lobe Pump/ Waukesha

Must Pumps

To Press or not to Press?

Whites press the juice from the grapes to minimize color Reds ferment on skinsto extract the color extraction

Yield as crushed must: 230gpt Calculated juice yield: 150 to 180 gpt

Calculated juice yield: 150 to 180 gpt

Tank filling

• In preparation for

primary fermentation fill

the tank to the proper

level:

• Do not exceed 80% of the

tank’s volume

• Do not drop below the

cooling coil or your

temperature controls will

be ineffective.

80% Full

White Juice Clarification

• After pressing settling and racking off

the lees is necessary

• Centrifugation and Lees filtration and rotary vacuum filtration are often used at larger wineries to save time and losses
• Often 1 to 2% solids is acceptable
• Most will settle between 35 and 50F

prior to inoculation

• Heat exchange may be necessary (around 65F)

Clarification Methods

Rotary Vacuum Drum Filter / Rotovac

Stacked Disk Centrifuge^ Lees Filter

Cold Settling

Pre-Fermentation Analysis

Why do we care about these?

• Brix – Sugar Concentration
  • By Refrac – Allows for check using same method used as with grape sampling
  • By Hydrometer – Initial sugar measurement
• pH – Number of protons in solution – Assess risk level
• TA – Titratible Acidity - used to make acid additions
• YAN – Yeast Assimilable Nitrogen (NH3 + AAN) – Measure Nitrogen for precise additions of DAP and Complex nutrients
• VA – Volatile Acidity – Indicator of spoilage
• Malic Acid – may allow for additional acid addition
• Microbiological Analysis – assess risk of microbial spoilage

Must Adjustments

• Based on chemical and sensory analyses the following decisions are routinely made: - Sugar - Low sugar must may require a concentration addition to elevate the potential alcohol - High sugar musts may require a water addition or a “de-alc” after fermentation - Acid additions - Low acid conditions may warrant an acid addition - Color enhancement - Maceration Enzymes - Thermovinification - Very dark red concentrate addition (ie. Mega Purple or Purple 8000) - Saignee - Cold soak (aka cold maceration)
• Note: When making additions it is preferred to make a water or juice slurry rather than adding a dry substance
• Mixing is key to homogenize additives
• END of Prefermentation - Once the processing is complete and additives are made your tank is ready for inoculation