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Juice Analyses

IR Juice Scan- Only for 100% grape juice 

  • Purpose: Snapshot of juice chemistry: brix, pH, titratable acidity, volatile acidity, alpha-amino nitrogen, ammonia, tartaric acid, and malic acid.
  • Technique: FTIR
    • Price- NYWGF Member*: $15; NY Non-Member*: $22.50;  Non NY: $30

Acidity: pH

  • Purpose: A measure of hydrogen ion concentration, pH affects microbial stability, concentration of molecular SO2, tartrate stability, and the perception of wine structure. 
  • Technique: pH meter
  • Analysis notes: Due to the buffering capacity of wine, pH is not always directly correlated with wine TA. Juice pH generally ranges from pH2.8 to pH4.
    • Price- NYWGF Member*: $3.75; NY Non-Member*: $6.00; Non NY: $7.50

Acidity: Organic Acid Panel (tartaric, malic, acetic)

  • Purpose: A measure of the primary acids found in wine.
  • Technique: HPLC (tartaric, malic, lactic, acetic)
    • Price- NYWGF Member*: $45; NY Non-Member*: $67.50; Non NY: $90
  • Technique: OenoFoss (FTIR) (100% grape juice only-malic, lactic, acetic)
    • Price- NYWGF Member*: $15; NY Non-Member*: $22.50;  Non NY: $30
  • Analysis notes: Malic and tartaric are the primary acids found in grape juice, with lesser amounts of citric acid.  Juice and wines produced from other fruits will be dominated by malic (apple) or citric (berries) acids.

Acidity: Titratable Acidity (TA)

  • Purpose: A measure of the acids in wine that can be neutralized with a base.
  • Technique: Autotitration (to pH 8.2) and pH meter
  • Analysis notes: Titratable acidity most closely corresponds to the sensory perception of acid strength; it should not to be confused with total acidity. Expressed in g/L tartaric acid equivalents.
    • Price- NYWGF Member*: $7.50; NY Non-Member*: $11.25; Non NY: $15

Sugars: Soluble Solids (Brix)

  • Purpose: This measurement of the dissolved compounds in grape juice yields the approximate sugar concentration.
  • Technique: refractometry
    • Price- NYWGF Member*: $3.75; NY Non-Member*: $6.00; Non NY: $7.50

Sulfur: Free and Total Sulfur Dioxide (SO2)

  • Purpose: Sulfur dioxide is used as an antimicrobial and antioxidant in wine production.
  • Technique: Foss FiaStar (segmented flow analysis)
  • Analysis notes: The legal limit is 350 mg/L, and concentrations above 10 mg/L (ppm) require the label to include the warning "contains sulfites." TTB CFR 4.22(b)(1)
    • Price- NYWGF Member*: $17.50; NY Non-Member*: $26.25; Non NY: $35

Trace Elements: Copper, Potassium, Calcium, and Iron

  • Purpose: The concentration of dissolved analytes can affect wine stability. Excess calcium and potassium can promote tartrate precipitation, and copper and iron favor oxidation.
  • Technique: Atomic absorbance
  • Analysis notes: Turn around on this analysis is about one week.
    The amount of residual copper in wine cannot exceed 0.5 ppm.   TTB CFR 24.246
    • Price- NYWGF Member*: $27.50 per element; NY Non-Member*: $33.75 per element; Non NY: $45 per element

Turbidity

  • Purpose: Turbidity is a measurement of juice clarity, which is reduced by the presence of suspended solids.
  • Technique: Nephlometer
  • Analysis notes: For sound grapes, a range of 100-250 NTU is generally considered optimum for a healthy fermentation.
    • Price- NYWGF Member*: $15; NY Non-Member*: $22.50;  Non NY: $30

Yeast Assimilable Nitrogen (YAN): Ammonia (NH3) and α-Amino Nitrogen (NOPA)

  • Purpose: Quantification of the total nitrogen available to yeast for fermentation.
  • Technique:  Enzymatic analysis
  • Analysis notes: Insufficient YAN can lead to slow or stuck fermentations and excessive hydrogen sulfide production.
    • Price- NYWGF Member*: $27.50; NY Non-Member*: $41.25;  Non NY: $55

Yeast Assimilable Nitrogen (YAN): α-Amino Nitrogen (NOPA) ONLY

  • Purpose: Quantification of the total nitrogen available to yeast for fermentation.
  • Technique:  Enzymatic analysis
  • Analysis notes: Apple juice generally has no ammonia, so only the α-Amino Nitrogen assay is required.
    • Price- NYWGF Member*: $20; NY Non-Member*: $30;  Non NY: $40

Consultation

  • Purpose: Troubleshooting or production planning beyond that related to service analyses
  • Analysis notes: Enology extension faculty and staff are available for consultation, but please note that we are not able to provide general product development assistance.
    • Price- NYWGF Member*: No Charge; NY Non-Member*: No Charge; Non NY: $150/hr

* Analyses are offered at a discount to all New York bonded wineries, home winemakers, and craft distilleries because a portion of testing costs (50% for members; 25% for non-member NY wineries) are subsidized by the New York Wine and Grape Foundation (NYWGF). We are unable to offer this discount to wine distributors or out-of-state wineries because of the nature of NYWGF funding.