April 2014 Issue of Wines & Vines

The Winery of the Future

Elements of it are operating today, say UC Davis professors

by Paul Franson
Gas conversion
By collecting CO2 from fermentations at the University of California, Davis, teaching winery, the gas can be converted to other side products or used for carbonation or biofuels.

While a few winemakers have consciously adopted a Luddite-like anti-technology position, most recognize that science and technology have led to better wines. Few places have done more to further the science of winemaking than the University of California, Davis, and its research and teaching winery and new sustainable research facilities (see “On Campus, Off the Grid” in the July 2013 issue of Wines & Vines) are already perfecting many old processes as they test new ideas.

The chair of the Department of Viticulture and Enology at UC Davis is David E. Block, a chemical engineering Ph.D. who is also a professor in the Department of Chemical Engineering and Materials Science there. Block formerly worked in another field utilizing fermentation, biopharmaceuticals.

He, along with another chemical engineer and veteran V&E professor, Dr. Roger Boulton, have devoted much time to considering the winery of the future. Block presented their thoughts at the 2013 Wine Executive Program conducted by the UC Davis Graduate School of Management.

The focus of the talk was incorporating new technology into winemaking, both in making wine and in improving management of utilities and waste.

The emphasis was solving key issues facing the wine industry, increasing wine quality, reducing processing costs and increasing sustainability while better managing natural resources. New technology can help meet all of those goals. This article summarizes Block’s comments.

The technologies that improve the winemaking process—and also improve wines—arise from a number of sources including R&D with a specific goal and the application of fortuitous inventions developed for other purposes. The wine industry can apply techniques developed for other industries including dairy processing, beer making and pharmaceuticals.

Fortunately, many changes can improve the wine while reducing cost; saving money doesn’t necessarily compromise quality.

Data helps decide harvest
Some of the improved technology is in instrumentation, which can provide better information for the winemaker to use in making decisions.

An example is deciding when to harvest. Once upon a time winemakers set harvest dates by the lunar calendar or saints’ days. In more recent times harvest was based on simple measurements of soluble solids and acidity. Many winemakers still don’t have access to instruments that can analyze tannins and anthocyanins. Instead they taste the grapes to assess these components, but their findings depend on their own experiences and inherent tasting abilities.

Fortunately, improvements in sensors combined with powerful computers—possibly even smartphones—can help provide quick field tests for polyphenols, including the use of near-infrared spectroscopy to measure anthocyanins.

Having more knowledge of juice composition can help predict how it should be fermented, including timing of harvest and processing steps, nutrient additions needed (if any) and even how to best manage the cap for red wines. This process can now be based on data from research and past harvests applied to the current juice’s composition.

Likewise, comparison of the must in a stuck fermentation with previous solutions, or best extraction of desired properties in red wine without excessive tannins, might be a matter of finding the optimum pattern in prior similar situations.

Grape sorting and pressing
Careful sorting of grapes has been widely adopted by high-end wineries to produce better wines, namely wines with intense flavors without undesired bitter tannins or green, overripe or moldy characteristics.

This initially was done via cluster selection, then with banks of workers removing by hand defective berries, jacks, leaves and other material other than good grapes. Now automated systems are becoming cost-effective as well as potentially superior. Some are simply shaking grids that allow only berries to pass through, but the most sophisticated involve real-time image analysis and help create the winery of the future today. The machine is “trained” with photographs of desired berries, and then as the berries move past a scanner the machine keeps those that match the images. Everything else is discarded. This equipment can process up to 10 tons per hour and leave only well-formed berries.

    Managing temperature gradients in tanks


    It’s well known that temperature has a big impact on phenolic extraction in red wine fermentations, but enologists are learning more and more about this complex subject through research. Temperature affects both the optimum length of fermentation and color and phenol extraction.

    However, gradients exist within tanks and the cap. This can cause different extractions of anthocyanins and tannins, for example, to occur at different tank levels and locations. Researchers at UC Davis are measuring these gradients with the aim of avoiding hot spots and guiding the length and timing of pump overs to control phenolic extraction.

    UC Davis has developed research fermentors that can be programmed for timing, frequency and length of pump overs with ongoing measurements of Brix. It is working on real-time sensors for color, phenolics and cell concentration.

    At present, temperature control in large fermentation vats is rather basic. One issue is that the cap can be significantly warmer than the juice below, causing faster extraction in the cap. This temperature difference can be controlled using cap management with pump overs or punch downs. However, the volume of pump over does not seem to affect extraction. Monitoring and controlling these parameters could improve the process.

Another process open to improvement through technology is pressing. At present, winemakers determine the length of time and pressure for pressing grapes mostly by experience, but online sensors could monitor the output of a press for phenolics and color density to control the pressure and separate wine into different fractions.

Improved information
One key to improving winemaking is to be able to access data and control processes. A laboratory information management system (LIMS) can store results of a range of instruments such as spectrometers, autotitrators or even high-performance liquid chromatography (HPLC) tests into a process database that can be accessed not only by winemakers and viticulturists but also others in purchasing and marketing.

A process-management system could likewise automate and control operations under a winemaker’s direction.

A supply chain/production-management system could go further and include data from vineyards, blending, bottling and packaging, even distribution and retailing in one database. It could also provide information needed to regulatory agencies like the TTB and ABC.

Implementing this level of automation can make some workers uncomfortable. One approach to overcoming that is to identify current automation needs and anticipate future automation needs as well as current management and operator comfort with automation.

Based on that, a winemaker can design for current needs with the current comfort level of automation (or just above it), yet install equipment capable of meeting future automation needs. The staff’s comfort level would rise as the winemaker increases automation with the existing equipment.

Conserving resources and treating wastes
In addition to improving the quality of wine and efficiency of winemaking, technology can help minimize the need for public utilities as well as improve treating and recovering waste products. By so doing, it can both reduce costs and increase the sustainability of winemaking.

One example of a technology that can be imported from allied industries is clean-in-place (CIP) systems for fermentation tanks and storage vessels. Spraying the inside of a tank with a hot caustic solution (typically sodium or potassium hydroxide) at high pressure can clean it thoroughly. The alternatives are today’s hand washing or individual cleaning units on each tank.

Cleaning tanks in place using automated systems provides better and more reproducible cleaning at lower costs with fewer personnel and less time, materials and waste. It’s also safer. There’s no dismantling of large equipment, contact with cleaning agents, hand scrubbing or crawling into tanks.

The factors involved in cleaning are contact time, temperature, concentration and cleaning agents, and turbulence or physical action. A CIP system must be able to vary all of these parameters.

Block pointed out that these systems have been used in milk processing since the 1960s and in the pharmaceutical business since the 1990s. “Of course,” he noted, “poor sanitation in those industries can kill you.” That’s not likely to occur with wine, but it can lead to poor quality. Breweries also use CIP systems.

UC Davis is starting to experiment with these systems, and it had the necessary plumbing installed in its research and teaching winery.

With the clean-in-place method, piping manifolds are provided for both supplying cleaning liquids and return of these liquids to a centralized system. These materials will eventually be recovered and reused by a specialized filtration unit.

Managing carbon dioxide
Carbon dioxide generated during fermentation is gaining increasing scrutiny from regulators as it contributes to pollution and is also a possible safety hazard. Standards are already enforced for large wineries in California’s Central Valley.

Since most fermentation tanks are closed, it’s relatively easy to collect the CO2 and pipe it to a central location. Some wineries already do this for safety reasons.

However, sequestering or using the CO2 makes a lot of sense, and the byproducts may even have value. After impurities are removed in gas absorption columns, the carbon dioxide can be reused for carbonating beverages, in processing or even feeding algae in ponds to produce biofuels.

The CO2 can also be bubbled through a solution of calcium hydroxide to produce calcium carbonate (chalk) used in wallboard or other products.

Minimizing water use
Water has always been tight in California, and it’s becoming more so, a situation highlighted by the current drought. Winemaking typically requires 4 to 6 gallons of water per gallon of wine produced, and most of that is for washing equipment. Some large wineries, however, use little more than 1 gallon of water for each gallon of wine produced.

Reclaiming and reusing water as well as reducing its use increases sustainability, may lower costs and may also become mandatory. Cleaning in place is one way to do this. Another way to reduce the water required is to capture and use rainwater.

Treating and reusing cleaning water is yet another approach. (We’re focusing on the winery, but of course recycled water can also be used for irrigation as well as flushing toilets, etc.).

To reuse wastewater it must first undergo coarse filtration or centrifugation to remove larger particles, then membrane filtration such as reverse osmosis to remove ions and other small impurities.

Another “waste” that can be used is heat. Wineries can recycle hot water streams used for bottling line sanitization and tank warming for heating spaces. Likewise, they can recycle cold streams used for tank cooling and cold stabilization in similar ways. Even better, they can abandon inefficient uses like tank cold stabilization in favor of energy-saving methods like ion exchange.

Alternate ways to generate energy are already popular. Photovoltaic cells are commonly used to generate electricity from sunlight, and some wineries also heat water with the sun. These arrays can be placed where they don’t occupy valuable vineyard land such as on rooftops, over leach fields and parking lots or even ponds. In the latter case, this also reduces evaporation from the pond. Roof-mounted arrays can reduce heat load on buildings.

Photovoltaic cells can also split water and release hydrogen, which can be stored and used to generate electricity in a fuel cell when sunlight is not available or is obscured.

Other ways to save energy come to mind, notably configuring buildings to use natural sunlight, daytime heating and night cooling as well as thick insulation to maintain temperatures. Heat pumps or underground arrays of boulders can store excess heat or cold to reduce energy needs.

The winery of the future will surely use technology to improve wine, lower production costs and increase sustainability. Even wineries that turn to traditional approaches like gravity feed, native yeasts and concrete and wood fermentors can benefit from instrumentation and automation that help guide winemakers to making better decisions.

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