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The purpose of testing and analysis during commercial winemaking is essential for TTB compliance.  It is also useful for improving wine quality.  Testing provides a basic technical framework which assists a commercial winemaker in predicting the impact of winemaking decisions on the resulting wine style and quality.   This presentation will provide a brief overview of different tests and analysis used while making wine in a commercial environment. We will review lab equipment, calculations, and evaluation methods which will allow you to scientifically assess resulting wine qualities, wine stability, and help finish a basic wine into a quality product. 

HARVEST

Harvest

Testing before, during, and after harvest

Sampling

Sampling

Purpose:  Know when to harvest.

  • Sample berries from different vines, from the shoulder, and the tip, random selection, or random whole clusters.  

  • Taste and see if ready for harvest.

  • Crush and press sample, at least 50ml.

  • Send to Lab for Test: send 50ml vial overnight courier to testing lab.  "Juice panel" for sugar content (Brix/SG), acid balance (TA), and nitrogen compounds (YAN).  Help predict when to harvest.

       ...or...

  • Test in-house including sugar, acid, nutrient requirement, if you have this capability --->

Sugar

Sugar Content

Purpose:  Predict potential alcohol, monitor fermentation progress.

  • °Brix: an estimate of sugar concentration and often as a predictor of potential alcohol, measured by refractometer

  • Specific gravity (SG): The SG of the juice called the Original gravity (OG), measured by hydrometer.

acid (pH & TA)

Acid Balance

Purpose:  Predict stability and SO2 requirements.  Assess acid additions.

  • Use meter specifically made for wine measurement.

  • pH meter should have two-point calibration.

  • pH meter should have 2-place decimal accuracy.

  • TA - titratable acidity, no correlation to pH.

YAN

YAN

Purpose:  Minimize incidence of hydrogen sulfide development.

  • Yeast Assimable Nitrogen (YAN).   berries from different vines, from the shoulder, and the tip. 

  • Simple Test requires formeldahyde, disposal issues.

  • Titrator for YAN considerable cost.  Not frequently used in small wineries.

  • Spectrophotometer (UV/Vis, FTIR)

  • Quick results.  More expensive but very versatile.

Crush & Press

Perform calculations, measure your additions.

Record Benchmarks

Measure & Record Benchmarks

Purpose:  Profile starting conditions of must or juice needed for planning a quality fermentation.

  • Tons of grapes, quantity of must, or gallons of juice.

  • Hydrometer SG/Brix readings

  • pH reading

  • TA reading

  • YAN reading

Calculations

Calculations

  • Purpose: Prepare for pressing, clarification, and fermentation stages.  Check for additives on hand.

  • Potential alcohol

  • Sugar additions (chaptalization) or water additions (amelioration)

  • Tartaric acid additions (bench trial)

  • Nutrient additions

  • KMBS Additions (SO2)

  • Enzymes (maceration & pectolytic) additions

  • Bentonite additions

  • Tannin additions

Reception

Reception

Measure and prepare additions.  Accurate, correct measurements for quality wine:

  • KMBS (SO2)

  • Ascorbic acid

  • Maceration Enzyme

  • Tannins for oxidation prevention

Crush & Press

Crush & Press

Measure and prepare additions:

  • KMBS (SO2)

  • pH and Tartaric acid (bench trial)

  • Pectolytic Enzyme

  • Check for residual pectin

  • Measure clarification/floatation additions

FERMENTATION

Fermentation

Measure, Innoculate, Malo-Lactic Fermentation (MLF/Conversion)

Prepare

Monitor

Stabilize Conversion (MLF)

 

  • Temperature of juice 

  • Test clarity (NTU) of juice

  • Water temperature - yeast preperation

  • Hydrometer - monitor for possible sugar depletion,

  • Measure & add sugar

  • Measure & add SO2, tannin, enzyme

  • Measure & add fermentation aids

  • Measure & hydrate sodium bentonite

1/3 of sugar depletion

  • Add some DAP/Fermentation Aid

  • Add sodium bentonite

  • Use your nose, detect H2S?

1/2 of sugar depletion

  • Add energizer, DAP, Fermentation aid

​

  • Measure ML nutrient

  • Monitor temperature, TA, and pH of wine

  • Prepare ML culture

  • Measure temperature during ML conversion

  • Test for completion of MLF

MATURATION

Maturation

Measure, Innoculate, Malo-Lactic Fermentation (MLF/Conversion)

Bio-Stability

Cold-Stabilization

Protein Stabilization

BOTTLING

Bottling

Bench Trials

Turbidity

Tartaric Stabilization

Bio-Stability

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