Starting a Lab in a Small Commercial Winery

The following is a guide meant to help establish a wine lab in a small (<10,000 cases annual production) to mid-size (<30,000 cases) winery.
Starting a Lab in a Small Commercial Winery - Articles
Starting a Lab in a Small Commercial Winery

Advantages of an In-House Laboratory

While having a laboratory in each winery may be challenging, there are several advantages to having an in-house laboratory:

  • Provide quick and immediate analytical results.
  • Improve record keeping and maintain accurate records of quality control parameters.
  • Saves on shipping and analytical costs associated with using wine lab services elsewhere.
  • Provides better analytical insight into the wines' quality.
  • Helps to identify key problem areas and can be used to avoid potential production problems.
  • Emphasizes a serious image towards the winery's customers.

Unlike the use of tasting and sensory analysis in a winery, analytical techniques offer an objective evaluation of a wine's chemistry and microbiological characteristics. Additionally, analytical parameters should not vary from operation to operation where as sensory analysis perception will vary from individual to individual. Done correctly, analytical results provide reliable, consistent numbers directly reflective of wine's chemistry, and, therefore, quality.

A Review of Basic Wine Analyses

Following a wine's chemistry through analytical tests provides a foundation for accurate records, knowledge on a potential wine problem, and the ability to watch chemistry trends in a specific variety (i.e., if a certain variety comes in from harvest with a high pH, high TA year-after-year).

There are several important topics that are not covered in this report, but vital to understand when discussing wine analysis. These topics include:

  • sampling techniques,
  • frequency of sampling,
  • use proper glassware during analysis (e.g., volumetric vs. serological pipets),
  • accuracy and precision, and
  • molarity vs. normality.

A list of available resources are cited at the end of this document for those that require additional information on those topics.

Most traditional wine analysis consists of "wet chemistry" methods, which means that analysis is completed in a liquid phase. pH and titratable acidity (TA) are measurements that evaluate acidity.

pH is a measure of the free hydrogen ion concentration in a solution (in this case, the "solution" is juice or wine), while TA measures those organic acids that are reactive with a base (Zoecklein et al. 1999). The base used for acid titrations of wine is typically a dilute solution of sodium hydroxide (commonly referred to as NaOH).

In wine, TA is commonly expressed as g/L of tartaric acid, as that is the dominant acid in grapes, and thus, wine. While both pH and TA measure acidity, TA is an indicator of how sour a wine will taste. On the other hand, the pH of a wine will relate directly to a wine's stability (e.g., cold stability, protein stability, color stability) and quality (e.g., presence and proliferation of microflora).

Sugar is commonly expressed as °Brix in grapes, juice, or must at harvest. The sugar concentration (or soluble solids) can be analyzed by refractometer or hydrometer prior to fermentation. During fermentation, most winemakers will switch to hydrometry as the ethanol development interferes with a refractometer. However, near the end of fermentation it is recommended that wineries switch to use a Clinitest, as it more accurately determines residual sugar in lower remaining sugar concentrations.

Wine is considered "dry" when it reaches under 1 g/L residual sugar. Most wineries try to reach this level of dryness to minimize the risk of potential spoilage or Brettanomyces (Brett) growth, which has been shown to utilize 0.1 g/L of residual sugar in wine (Arvik and Henick-Kling, 2002). However, Zoecklein et al. (1999) notes that a wine can never reach 0% residual sugar due to residual pentoses that are not fermentable by yeast.

For more accurate analyses of residual content in wine, a winery can consider the use of an enzymatic assay analyzed with use of a spectrophotometer. A spectrophotometer is an instrument that measures the amount of light that passes through a sample. While the original investment for this equipment can be expensive, a spectrophotometer can be used for multiple wine analyses if the appropriate kits are purchased. This includes analyses to measure malic acid concentration, primary amino acid content (for YAN), ammonia concentration (for YAN), and acetic acid concentration. Enzymatic kits for these analytes contain reagents and enzymes that cause a chemical reaction to occur in the juice or wine, specific to each analyte. A "before" and "after" sample is measured by an absorbance reading using the spectrophotometer.

The importance of Yeast Assimilable Nitrogen (YAN), which is the total of ammonia + primary amino nitrogen (PAN) is also well documented in the literature. For a quick reference on YAN and how it relates to nutrient strategies during fermentation, please refer to the Penn State Wine Made Easy Fact Sheet: Nutrient Management .

The YAN value is important as it will determine the nutrient strategies utilized during primary fermentation. Too little or too much YAN at the start of fermentation can lead to higher risks of developing hydrogen sulfide (rotten egg aromas) during primary fermentation. The development of hydrogen sulfide leads to a decreased perception of fruit and is often considered a wine flaw.

Lab Analysis Set Up

In-house labs are recommended to have documented safety procedures as well as standard operating procedures (SOPs) and protocols available to all employees. Protocols should be reviewed for accuracy and should dictate what lab equipment will need purchased or maintained over time to complete the analysis.

The following is a generalized list of materials you will probably need to get started.

pH

  • pH meter with electrode & Automatic Temperature Compensation (ATC) probe - Potential suppliers:
    • Enartis Vinquiry
    • Fisher Scientific
    • Sigma-Aldrich
    • VWR
  • Electrode storage holder & solution (or pH 4.00 buffer)
  • 50 mL glass beakers
  • pH buffers (3.00, 4.00, 7.00, 10.00)
  • Distilled water
  • Optional: stir plate (with or without hot plate) and stir bars

Titratable Acidity (TA)

  • 25 or 50 mL buret - Potential Suppliers:
    • Enartis Vinquiry
    • Presque Isle Wine Cellars
    • Scott Labs
  • Buret stand
  • Buret clamps
  • Stir plate (with or without hot plate)
  • Stir bars
  • 250 mL glass beakers
  • 5 mL volumetric pipet
  • Degassing source/sparge stone (for wine samples)
  • Normalized Sodium Hydroxide (NaOH)
  • Normalized Hydrochloric Acid (HCl) for TA Calibration
  • Phenolphthalein or pH meter (for endpoint identification)
  • Distilled water

Brix for Juice Analysis

  • Refractometer
  • Distilled water
  • Kim Wipes
  • Disposable Pipets

Yeast Assimilable Nitrogen (YAN)

Ammonia by Ion-Specific Electrode

  • Ion-specific electrode (with pH meter; must have millivolt reading capability)
  • 250 mL glass beakers
  • Stir plate (with or without hot plate)
  • Stir bars
  • 1L volumetric flask
  • Ammonium Chloride (NH4Cl)
  • De-ionized water
  • 1N Hydrochloric Acid (HCl)
  • 10M Sodium Hydroxide (NaOH)
  • Ammonia standards (bought or prepared from Ammonia Stock Solution)

Ammonia by Enzymatic Kit

Free Amino Concentration

  • Spectrophotometer (Abs. at 335 nm or 340 nm)
  • Free Amino Acid Nitrogen Enzymatic Kits - Potential Suppliers:
    • Enartis Vinquiry (Vintessential Kit)
    • Megazyme
  • Vortex Mixer
  • Centrifuge & centrifuge tubes OR Whatman filters (to remove gross solids)
  • Cuvettes
  • Cuvette rack
  • Parafilm
  • Eppendorf pipettors (*see above*)
  • Eppendorf pipet tips
  • Small (~100 mL) volumetric flasks (for isoleucine standards, depending on kit)
  • Stop clock
  • Distilled water

Malic Acid Concentration

  • Spectrophotometer with UV capability (Abs. at 340 nm)
  • Cuvettes
  • Cuvette rack
  • Eppendorf pipettor (*see YAN, above*)
  • Eppendorf pipet tips
  • Malic Acid Reagent Kit - Potential Suppliers:
    • Enartis Vinquiry (Vintessential Kit)
    • Roche Custom Biotech

Microbiology - Microscope

  • Phase Contrast Microscope
  • Microscope slides
  • Cover slips
  • Lens paper
  • Pasteur pipets
  • Immersion oil
  • Methylene Blue (Yeast stain)

Alcohol Concentration

  • Ebulliometer - Potential Suppliers:
    • Dujardin-Salleron
    • Enartis Vinquiry
    • Presque Isle Wine Cellars
  • Thermometer (86-102°C)
  • Dial alcohol scale
  • Alcohol lamp (fueled with >90% ethanol)
  • Distilled water

Volatile Acidity

  • Cash still assembly
  • TA assembly (with 2 burettes--50 mL)
  • 250 mL Erlenmeyer flasks
  • 10 mL volumetric pipet
  • 5 mL serological pipet
  • Pipettor
  • 0.1N Sodium Hydroxide (NaOH)
  • Phenolphthalein
  • 1+3 Sulfuric Acid
  • 0.02N Iodine
  • Starch Indicator

Free and Total SO2 (Sulfur Dioxide)

Aeration Oxidation Set Up (Free SO2)

  • AO Assembly
    • Metal stand
    • Impinger set
    • 100 mL side port flask
    • Support ring for flask
    • Bubbler/stopper (into side of side port flask)
    • Stopper/glass tubing adaptor (into top of side port flask)
    • 3-fingered clamps (2 to 3 per set up)
    • Clamp holders
    • Tygon tubing
  • Vacuum: airejector aspirator
    • Quick disconnect plastic connector
    • Amber latex tubing
    • Flowmeter (0.4-40 mL/min)
  • 20 mL volumetric pipet
  • 10 mL serological pipet
  • Pipettor
  • TA assembly
  • 3-30% Hydrogen Peroxide (diluted to 0.3%)
  • 25% Phosphoric Acid
  • 0.01N Sodium Hydroxide (NaOH)
  • SO2 Indicator

Ripper Set Up (Total SO2)

  • 250 mL Erlenmeyer flasks
  • 25 mL serological pipet
  • 10 mL serological pipet
  • 5 mL re-pipettor (for Sulfuric Acid)
  • Pipettor
  • TA assembly
  • 0.02N Iodine
  • Starch Indicator
  • 1+3 Sulfuric Acid
  • 1N Sodium Hydroxide (NaOH)

Extra Reading, Resources, and Protocols

  • Chemical Analysis of Grapes and Wine: Techniques and Concepts byPatrick Iland, Nick Bruer, Greg Edwards, Sue Weeks, and Eric Wilkes. (2004) ISBN: 0-9581605-1-1
  • Wine Analysis and Production by Bruce W. Zoecklein, Kenneth C. Fugelsang, Barry H. Gump, and Fred S. Nury. (1999) ISBN: 0-8342-1701-5
  • Wine Microbiology by Kenneth C. Fugelsang and Charles G. Edwards. (2007) ISBN: 0-387-3341-X
  • Microbiological Analysis of Grapes and Wine: Techniques and Concepts by Patrick Iland, Paul Grbin, Martin Grinbergs, Leigh Schmidtke, and Alison Soden in conjunction with The Interwinery Analysis Group. (2007) ISBN: 0958160544
  • Introduction to Wine Laboratory Practices and Procedures by Jean L. Jacobson. (2006) ISBN: 0-387-24377-1
  • Food Analysis by S. Susanne Nielsen. (2003) ISBN: 0-306-47495-6
  • "Lab Equipment: Affordable Products Allow Small Wineries to Automate Labs" by Curtis Phillips in Wine Business Monthly, July 2006.
  • "Brettanomyces bruxellensis occurrence, growth, and effect on wine flavor" by Torey Arvik and Thomas Henick-Kling in Practial Winery & Vineyard Journal, May/June 2002.
  • Enartis Vinquiry Website
  • Presque Isle Wine Cellars Website
  • ETS Laboratories Website
  • Bruce Zoecklein's Website

Authors

Denise M. Gardner