Overview Laboratory

This section covers our laboratory for measuring the chemical characteristics of grape juice, must in fermentation and maturing wine. This page explains why we need a laboratory, what we analyze and measure, and how we calibrate the instruments. The following pages describe each measurement and the associated laboratory process.




We know little, but we measure a lot

When I compare the art of viticulture and winemaking to my professional background in engineering and finance, I sense we are still in the dark ages. We know good wine when we drink it, but we have little scientific understanding of the chemical processes that lead to good wine. We have learned the importance of measuring specific physical and chemical characteristics of grape juice and wine mostly because we know what ranges they should be in to make drinkable wine and what to do if they are not. We do not understand most chemical processes leading to good wine and what and how to measure to optimize these processes. We know famous vignerons who have developed successful processes for their grapes, leading to high-priced wines. Still, they don't understand the underlying science – they are artists who have refined their craft based on recipes handed down over generations or based on processes they chanced upon.

The following questions and answers highlight how limited our current understanding is:

1. Exactly which chemical compounds in what combination in mature wine (phenolics and flavor compounds) create that wonderful combination of sensory experience in smelling, tasting, and drinking great wine? We don't know. We know which chemicals create bad tastes and smells, and we know the composition of some of the substances which are associated with specific flavors

2. Exactly how do specific cellaring processes (aging in barrels, adding wood chips, racking, etc.) change the chemical composition of wine? We don't know because we don't know the chemical composition of wine in the first place, let alone the change therein. But we know that specific cellaring techniques have led to wine selling for a higher price.

3. How do the steps in winemaking (enzyme addition, cold soak, fermentation, extended maceration, pressing) extract the "good" phenolics and flavor compounds from the grapes? What should we measure to guide us better on what to do, when, and how much? We still rely primarily on the smell and palate of experienced winemakers and their past successes to guide us through the art and craft.

4. What happens in the vineyard concerning phenolics and flavor compounds in the grape? How can we make the vines produce the suitable phenolic composition in the grapes, which 

So, my argument is: we still know (academically) very little about what exactly makes superb wines and why. We know a fair amount about the acceptable ranges for chemical properties we can easily measure. We also know how to intervene in winemaking to get these measures back into acceptable ranges. So science has helped us reduce the amount of lousy wine made, but we still need to understand more of the chemical processes for science to help us make outstanding wines.

Gifted and experienced winemakers can smell and taste the slightest aberration in wine – thus, the laboratory is not very important in small boutique wineries. In large wineries with industrialized processes, laboratories are essential to ensure consistency. We are a small boutique at best and lack the gifted nose and palate, so the laboratory is vital for us.




Measurement tools

Laboratory tools have become very sophisticated and expensive as technology has progressed, and industrial scalability has become essential. Consequently, many wineries have outsourced this function to specialized providers (e.g., ETS, Enartis Vinquiry, Signature Labs, etc.). Given our goal to keep the whole vineyard and winery process in-house, we decided to maintain a laboratory – it defies economic logic for the sake of understanding the entire picture.

While our laboratory is well equipped, it is no match to the sophisticated equipment currently employed at top commercial wineries and leading universities (primarily for various types of chromatography, spectrometry, nuclear magnetic resonance spectrometry, etc.).

The "wet" lab

In the old-school-"wet"-lab, we measure chemical properties by changing the chemical characteristic or composition of the sample to be measured: we measure boiling points, we add known quantities of a given reagent until a property changes, etc. In "wet" labs, you see a lot of glassware and bottles with reagents. Time-consuming processes are needed to measure every property of every sample.

The main benefit of "wet"-labs is cost: fixed costs are $2,000 – 5,000 for glassware and tools. The variable cost averages $3 – 5 for reagents per sample. The main disadvantage is labor: A single measurement takes 5 to 45 minutes.

The new approach: spectrometry

The new approach has three steps: a) centrifuge samples to separate sediments, b) measure the spectral density over a wide range of frequencies, and c) derive, with specialized software, specific chemical properties of the sample from its spectral density curve.

We currently use two types of spectrometer setups:

  • An OenoFoss Analyzer (www.foss.us/industry-solution/products/oenofoss/ ) for the basic chemical properties: Brix, Alcohol, Glucose, Fructose, Density, pH, Total Acidity, Volatile Acidity, Malic Acids, and Lactic Acids,

  • A Genesys 10S UV-Vis spectrometer from Fisher Scientific with a 0.2mm quartz flow cell from Starna Cell fed into cloud software from WineXRay to measure phenolics (www.winexray.com).

The main benefits of spectrometry are speed and zero variable costs: less than 3 minutes per sample with 6-12 simultaneous measurements. The main disadvantage is high fixed costs: $5,000 – 40,000 per setup. Thus spectrometry can only be justified when hundreds of samples are to be analyzed yearly.

We introduced spectrometry in 2013 when we started measuring phenolics. We stopped using most of our "wet"-lab tools in 2017 when we bought an OenoFoss Analyzer to handle the increasing number of basic measurements.



What do we measure, and how?

Our approach to measurements has changed significantly since 2009. We started with a well-equipped "wet" lab to take basic measurements. We soon realized that measuring samples in a "wet" lab every time we interacted with the grapes, must, or wine became impractical – far too time-consuming. We started using spectrometry in 2013 to measure phenolics, and we bought an OenoFoss Analyzer in 2017 to measure the basic chemical properties. In 2019 we started experimenting with measuring dissolved CO2, dissolved oxygen, and, in 2021, Oxygen Reduction Potential ("ORP").

As of 2023, the primary laboratory instruments we use are:

  • OenoFoss Analyzer for measuring the basics: sugars (Brix, Glucose, and Fructose), alcohol (% Alcohol, Density), acids (pH, Total Acidity, Volatile Acidity, Malic Acids, Lactic Acids, Tartaric Acids, Gluconic Acids), nutrients (Yeast Available Nitrogen: Alpha Amino Acids, Ammonia)

  • WineXRay for measuring phenolics: Anthocyanins (bound, free, and total), Tannins, and Total Iron-Reactive Phenols ("TIRPs"). The setup includes a centrifuge, a sipper pump, a spectrometer, and a laptop to connect to the WineXRay cloud for analysis.

  • Enotrex for measuring essential characteristics of maturing berries (with OenoFoss), Potential Anthocyanins (with WineXray). The setup includes a precision press, a temperature-controlled bath, and WineXRay.

  • @Accuro for measuring Oxidation Reduction Potential ("ORP") to monitor oxygenation during fermentation

  • Hanna HI84500 Titrator for measuring SO2

  • DOTek from Flotek and Hanna HI9148 for measuring dissolved oxygen

  • Carbodoseur from Laboratoires Dujardin-Sailleron for measuring dissolved CO2

Each of the following seven pages describes these instruments. The five pages which follow illustrate the now outdated "wet" lab measurement methods:

  • Brix measured with Optical Refractometers and Hydrometers

  • Alcohol measured with Eboulliometers

  • Acidity (pH and Total Acidity) measured with a pH meter and titration

  • Volatile Acidity measured with a Cash Still

  • Malic & Lactic Acids measured with Paper Chromatography

Instrument calibration

Instruments used in wet labs should be calibrated every time before use. This calibration is time-consuming and requires calibrated reagent solutions with a relatively short shelf-life (a few months at best). This makes wet labs cumbersome.

Spectrometer-based instruments, which do not depend on chemical reactions, are usually calibrated by the manufacturer against typical must and wine samples from the winery using sophisticated wet-lab assays. This is expensive, but their calibrations are good for extended periods (years).

Measuring the chemical properties during fermentation is challenging because the must's chemical composition continually changes as it ferments (hour by hour). This makes many wet-lab measurements impractical – they take too much time. For the same reason, spectrometer-based instruments cannot be calibrated for measurements during fermentation. However, the calibration adjustments can be interpolated from the results measured at the beginning and end of the fermentation when the samples are stable enough for wet-lab calibration. Details on how we calculate these adjustments can be found in the Data Management Section.

Here is a link to a pdf file of the Laboratory section as of May 16, 2023

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Last updated: March 3, 2023