A few weeks ago, I was asked two simple yet crucial questions during an interview with the Sustainable Restaurant Association: what does the word “waste” mean to you? What elements would you include within this definition?
In considering my response, I realized how important it is to define and correctly understand what the word “waste” means and encompasses in order to establish effective reduction strategies.
With this idea in mind, I began asking wine world professionals these very same questions, and the results of this exercise were very enriching.
By definition, the term “waste” refers to a material, substance, or by-product that is eliminated or discarded as no longer useful or necessary once a particular process has concluded.
When looking at wine production, we could say that each stage of the process generates a certain amount of different waste products.
Let’s start with the vineyard. When I posed the questions to Jeff Baccus, winegrower at Advanced Viticulture, he explained that vineyard waste includes a number of things, starting with chemical runoff and soil accumulation, the containers the chemicals are stored in, as well as refuse generated during the manufacture and transport of agrochemicals.
Certain vineyard tasks involve the use of tractors, which run on fossil fuels and therefore generate waste. Their maintenance involves oil changes, coolants, and the upkeep of brakes and tyres, all of which also generates waste.
Likewise, transporting workers and equipment to the vineyards requires the use of vehicles, with their own fuel and maintenance needs that in turn produce waste. If the vineyards are located in remote areas, they need to be equipped with portable bathrooms for the staff, thereby generating a series of waste products derived from their use, cleaning, and maintenance.
Finally, systems designed to protect the vineyards from increasingly common weather phenomena such as frost require fossil fuels, thereby also generating waste in the form of greenhouse gas emissions.
If we turn our attention to the winery, we will find a variety of waste products, some of which overlap with those found in the vineyard. Here refuse generally falls into two categories: organic and inorganic waste.
The vast majority of the refuse (80–85%) generated in the winery can be classified as organic.
Organic waste primarily refers to elements that derive from what is known as biomass, that is to say, leftover parts of the grapes themselves: grape pomace, seeds, pulp and skins, stems, leaves, lees, and tartrates/bitartrates that remain at the end of the winemaking process.
According to certain wineries like Adega de Redondo in Portugal, these organic residues are not considered waste as such, but rather by-products.
Most wineries obtain an added value from these products by selling them to third parties, such as officially authorized distilleries. In other words, they provide the raw materials to make spirits, alcohol, tartaric acid, and other products that can then be reincorporated into the making of wine and spirits, as well as alcohol used in manufacturing gels and cosmetics.
Another way of giving new use and value to grape-related organic waste is through bioconversion, whereby micro-organisms, bacteria, or fungi transform sugar-containing waste into a variety of natural compounds, such as ethanol, organic acids, or amino acids.
The organic waste produced by the wine industry can be used as biomass to obtain methanol or ethanol. Whereas biomethanol is usually extracted from leftover pomace, bioethanol is obtained from solid waste, such as grape skins or dried lees. In both cases, the process calls for anaerobic fermentation.
At Foley Family Wines in California, where no organic by-product is cast aside, we find a clear example of what it means to bring new value to organic waste. All solid waste matter is prepared for sale, along with any remaining lees and bulk wine left over at the winery.
In short, these days, organic waste can work its way into the circular economy of the wine industry, as long as it isn’t simply dumped, making it possible to transform refuse into ingredients to make new products.
The winery, however, also generates inorganic waste. This kind of waste derives from minerals and synthetic products, which do not decompose or break down naturally, or if they do, the process may be too slow.
In the winery, the majority of the inorganic waste pertains to leftover packaging, such as boxes, plastic packing materials, glass bottles, scrapped bottle closures, labels and the backing web needed to apply them in the bottling line, discarded containers used in the process of cleaning or treating the wines, etc.
In these cases, the strategy to reduce the amount of inorganic waste rests on what is known as the 10R principle or the 10 “R’s”. This refers to a list of 10 action verbs, all starting with the letter “R”, which are built into the idea of a circular economy.
These 10 circular strategies are arranged in order of preference: “refuse”, as in doing away with the need for certain materials, components or products, tops the list (the most valuable strategy), and “recover”, as in recovering the energy contained within a product through incineration, comes in last (the least desirable).
When we talk about waste in the winery, it is also important to consider wastewater. This is a regularly occurring form of waste given the number of cleaning operations that are carried out in the winery during the winemaking process. Wastewater contains a number of pollutants, both organic and inorganic.
The exact composition of the wastewater varies greatly, depending on the type of operation being carried out in the winery at any given moment, along with any possible treatments that are implemented. For this reason, the reuse of wastewater should be closely analysed for each individual farm.
In any case, an increasingly industrialized market of this size requires the maintenance of a constant production process, and the implementation of appropriate and effective waste management and reduction strategies.
Furthermore, seeing how waste management involves additional and steadily rising costs, the use of waste reduction strategies will not only have a positive environmental impact, but makes financial sense as well.
Marta Juega, Ph.D.