Our Approach to Eco-Friendly Winemaking
Words by Mark Driver
We’re trying to be as ‘sustainable’ as we can. We’ve adopted various practices across the estate to reduce our carbon footprint and reduce our impact on the natural environment, and Decanter magazine reported our ambition to be one of ‘the greenest’ wine producers in the world. But what do we mean by sustainable and what can you do to be environmentally sensitive when consuming wine?
The dictionary definition of Sustainability is ‘the avoidance of the depletion of natural resources to help maintain an ecological balance’, and the motivation for writing this blog was to reply to an article in the Drinks Business that quoted a report by UC Davis Professor, Roger Boulton, saying that “Carbon from the winemaking process is five times more concentrated than planes and cars. A litre of juice produces 60 litres of carbon dioxide. Why aren’t we trapping it?”
To me, that’s a crazy statement and it was probably taken out of context because grapes and vines sequester (trap) carbon dioxide. The average litre of wine, after considering the carbon/energy used in its production from vineyard tractors and maintenance, to grape fermentation and all that happens in the winery, sequesters or traps 300g of carbon per litre of wine (click here). The problem is caused after this when we then bottle and then transport the wine, which then burns carbon. According to the American Association of Wine Economists: “The CO2 emitted during fermentation represents less than 3 percent (around 100 g) of the overall CO2 emissions resulting from the production and delivery of one bottle of wine.”
The science is as follows: Two CO2 molecules are created from every glucose molecule, 180.16g of glucose yields 88.02 g of CO2. This yield represents a 48.86% conversion ratio (88.02g / 180.16g), thus 1 litre of juice at 20°Brix (20% glucose, by weight, the equivalent of 11.5% potential alcohol) releases 97.3g of CO2.
Wrap.org estimate that CO2 emissions associated with transport vary per bottle, from 432g for an Australian Wine imported into the UK, to 119g for a French Wine. However, if the wine is imported in bulk, as most Australian wine and some French wine is, those figures fall to 268g and 81g respectively.
However, the biggest effect on carbon emissions is packaging and in particular bottle weight, which accounts for an estimated 85% of that. The average still wine bottle weighs 500g. Reducing that to 400g will save approximately 100g of CO2 emissions. According to the Wrap report, the combined benefits from bulk shipping and bottling with the lightest 300g bottle would save 375g per bottle.
Perversely organic viticulture has minimal effect on the environmental impact compared to standard farming practices. According to a report on the ‘Life cycle environmental impacts of wine production and consumption in Nova Scotia, Canada’, the improvements were “albeit marginal at best”, partly because vineyards use relatively low levels of chemicals on vines and when you consider the associated lower yields and other impacts the effect is minimal.
To me sustainability is multi-layered, it’s everything we touch. It’s not just about the use of carbon or energy or chemicals. It’s about how we treat our soils, our use of water and all the inputs we have in the winemaking process, the whole environment. However, the biggest impact on the environment from wine production according to research I’ve read is, in decreasing order; glass bottles, cardboard boxes, fuel, electricity, closures (corks, caps, etc), pesticides and fertilizers. So, what are we doing?
- Sadly, we can’t do much about our bottle weight as we bottle ferment our wines and the bottle needs to be able to withstand 6-bar of pressure, but we have chosen a bottle which is 20g lighter than the traditional bottle.
- We use modern Fendt tractors that are far less polluting than older tractors and we try to do several things in the same pass, such as mowing and vine trimming. We’re hoping to trial an electric tractor this year.
- We generate electricity from photo-voltaic cells behind the winery and on the flint barns roof, which contribute significantly to our energy needs in the winery and associated buildings. We wanted to erect wind generators, but we’re in the South Downs National Park and whilst they’re encouraged off the coast, they’re not very popular around here.
- We have a strict recycling policy across the estate and a cycle to work policy, and several of our staff cycle to work.
- We use a mixture of organic and conventional practices in the vineyard: we use certain chemicals to tackle mildew and we use limited amounts of herbicide to keep down weeds under the vines, but we also use an under-vine mower and grow plants between rows that encourage beneficial insects, such as parasitic wasps which help reduce vineyard pests.
- We use organic fertilisers such as a liquid seaweed product, which we spray directly onto the foliage, covering three rows at a time, and we use council provided compost on the vines.
- When we built the Winery buildings we used locally sourced flint in our walls and oak sourced from within 50miles of the Estate.
- Making wine uses a lot of water – between 3-10 litres for every litre produced – so we take water from a borehole on the land, filter it and after using it we treat it and put it back into the land, so we’re self-sufficient in water. Note: we don’t irrigate the vines.
- We use Electro-Dialysis (ED) to cold-stabilise our wine, to prevent tartaric acid crystals forming in the wine if you leave it in a very cold fridge. The conventional process is to freeze your wine for 72 hours to knock out the tartaric acid crystals before bottling, which uses huge amounts of energy. ED uses far less energy and requires less water, as you don’t have to clean the crystals out of the tank after this process, and it’s 100% safe, and I think kinder to the wine.
- We chose to use a dark green, almost amber bottle, to prevent the risk of light shock. Darker bottles tend to be made of more (typically 80%) recycled glass.
- Lastly, we use mainly local labour – our vineyard team typically come from within 15 miles of the estate and many car share. We also use the flint barns to accommodate workers during harvest to reduce traffic on and off the Estate.
So what else can we all do to reduce the carbon footprint of the wine we consume? It seems the most logical thing is to buy locally made wine. Buy English wines and recycle your bottles. However, let’s put this into perspective – using 1 litre of petrol generates 2.4kg of CO2 and gets you approximately 6 miles, the equivalent of two bottles of wine, according to many people! So, cycle to your off license and buy English wines.