Canning and Climate: Reducing Food Waste
- David Bell
- 7 days ago
- 9 min read
Food waste is a massive issue in the UK, with households discarding 7 million tonnes annually, costing families around £1,000 a year. This waste contributes to 8-10% of global greenhouse gas emissions, with decomposing food in landfills releasing methane, a gas far more harmful than CO2. Canning offers a straightforward way to tackle this problem by preserving surplus produce for up to five years without refrigeration, cutting waste and reducing emissions.
Key points:
10 million tonnes of food and drink wasted yearly in the UK; households account for 70%.
Food waste generates 18 million tonnes of CO2e emissions annually in the UK.
Canning extends food shelf life, prevents spoilage, and reduces the need for refrigeration.
Items like bruised apples or blemished tomatoes can be preserved instead of thrown away.
Canning is easy to do at home and helps cut costs while making better use of seasonal produce. It’s a practical step for households and a meaningful way to reduce waste and emissions.
The Climate Impact of Food Waste
Food waste has a significant impact on climate change, primarily through the release of methane as it decomposes in landfills. Beyond that, it represents a massive waste of resources like water, energy, and land that go into producing food [8][3].
"Food waste contributes to climate change and environmental degradation in two ways; through release of gases (such as methane) from its breakdown in landfill and through waste of the energy and resources required to produce wasted food." - House of Commons Library [8]
The numbers paint a stark picture. In 2021/22, food and drink waste in the UK was linked to around 18 million tonnes of CO2 equivalent emissions, with households responsible for 60% of this waste by weight [8]. In 2022, UK households alone discarded 6.0 million tonnes of food and drink, producing an estimated 16 million tonnes of CO2e [9][4]. Items like meat, fish, and pre-prepared meals have the highest greenhouse gas footprint when thrown away [8][9].
On top of that, 3.9 million tonnes of household food waste still end up in black bins, missing the chance to be composted or processed through anaerobic digestion [9][7]. The land currently used to grow food that ultimately goes to waste could be repurposed into forests or grasslands, which would help absorb carbon from the atmosphere [3].
The financial cost is just as staggering as the environmental toll. UK local authorities spend more than £500 million each year managing and treating household food waste [9]. Meanwhile, the value of edible food wasted by households is estimated at £17 billion annually - equivalent to about £1,000 for a family of four [8]. Addressing this issue through practical solutions, such as canning surplus food, could help ease both the environmental and economic strain.
How Canning Reduces Food Waste
Canning helps tackle food waste by significantly extending the shelf life of surplus or less-than-perfect produce, all without relying on energy-intensive refrigeration. This method transforms fruits and vegetables that would otherwise spoil quickly into preserved goods that can last anywhere from one to five years when stored correctly [12]. As a result, it plays a key role in cutting down the amount of food that ends up in landfills.
This process is especially beneficial for saving produce that might otherwise be discarded. For example, an apple with a small bruise or a tomato with a minor blemish can be trimmed and preserved, rather than being thrown away [6][10].
The Canning Process Explained
The steps involved in canning highlight why it’s such an effective way to reduce waste. It begins with washing, peeling, and trimming the produce to minimise the presence of microorganisms [10]. After that, the food is heated - either through blanching or the hot-pack method - to boiling temperatures, which inactivates enzymes that would otherwise alter the food’s colour, texture, and flavour [11].
The next step involves packing the food into clean jars, leaving a small amount of space at the top - typically about 0.6 cm for jellies and 3.2 cm for meats - to allow for expansion during heating [10][11]. Once sealed, the jars are processed using one of two methods. High-acid foods like fruits and pickles are processed in a boiling-water bath at 100°C (212°F), while low-acid foods such as vegetables and meats require pressure canning at higher temperatures - 115°C to 121°C (240°F to 250°F) - to eliminate heat-resistant bacteria [10][11]. As the jars cool, the contents contract, creating a vacuum seal that keeps the food safe from recontamination [10][5].
"The most critical step in ensuring safety in canning is processing in a boiling‐water bath or pressure canner. Processing destroys microorganisms and creates the desired vacuum for a good seal." – University of Minnesota Extension [10]
Managing Surplus and Seasonal Harvests
Canning proves especially valuable during peak harvest seasons when fresh produce is abundant but immediate use is limited. To ensure the best quality, most vegetables should be canned within 6 to 12 hours of being harvested [6][10].
The hot-pack method is particularly helpful for managing surplus produce. By heating the food to boiling before packing it into jars, this technique removes air from the food tissues, preventing discolouration and slightly shrinking the food. This shrinkage allows more produce to fit into each jar, making the most of the surplus [6][10]. Once canned and stored in a cool, dark place at temperatures between 10°C and 21°C, these goods require no refrigeration, eliminating the energy costs and waste that come with cold storage [6][10].
Benefits of Canned Foods
Environmental Advantages
Canned foods do more than just reduce food waste - they also bring some notable environmental perks. One key benefit is that they don’t need refrigeration, cutting down on energy use across the supply chain. Unlike fresh or frozen foods, which require cold storage during transport, in shops, and at home, canned goods can be safely stored at room temperature. Plus, the metal used for their packaging - mainly steel or aluminium - can be recycled endlessly without losing quality, contributing to a circular economy.
In the UK alone, more than 2.5 billion cans are recycled each year, preventing around 125,000 tonnes of solid waste. Recycling also reduces carbon emissions significantly, as each recycled steel can saves over one and a half times its weight in CO₂. Even a single recycled can makes a difference - it saves enough energy to power a 10W LED bulb for 24 hours, watch an hour of TV, or run a full load of laundry [2]. The recycling process itself is efficient too, using magnetism for steel and eddy currents for aluminium, reinforcing the environmental benefits of canned foods.
Practical and Nutritional Advantages
Canned foods are a practical choice for households, offering a mix of convenience and nutrition. Thanks to the canning process, food is preserved at its peak, locking in essential vitamins and nutrients without the need for added preservatives. Since the food is fully cooked inside the can, all it usually needs is a quick reheat before serving. As Canned Food UK explains:
"Because the canning process locks in nutrients and vitamins of fresh ingredients at the height of their ripeness, the flavours are delicious." – Canned Food UK [2]
This makes canned foods a time-saver and a cost-effective alternative to fresh options, especially for those on a budget. For anyone watching their sodium intake, there are low-sodium varieties available, or you can simply rinse the contents to reduce salt without losing out on nutritional value.
How to Maximise Canning's Impact
What Consumers Can Do
Choose fresh, ripe produce at its peak for the best results. For vegetables, aim to can them within 6 to 12 hours of harvest to maintain quality and safety [6]. If you're shopping rather than harvesting, consider buying items close to their "best before" date. These are often still perfectly good for preserving and help combat food waste. For instance, one in three loaves of bread is discarded due to date labels, even when it's still edible [7].
When canning, the hot-pack method is a great way to extend shelf life. Be sure to follow recipe guidelines for headspace, and store your jars in a cool, dark spot where the temperature stays between 10°C and 21°C. For the best quality, aim to consume your home-canned goods within a year [6].
By regularly canning surplus or nearly expired items, you can make a real dent in household food waste. This is especially important considering UK households throw away 4.4 million tonnes of edible food each year [13].
Policy and Industry Actions
While individual actions are vital, policy and industry play a crucial role in making a broader impact. In March 2026, the Department for Environment, Food and Rural Affairs (DEFRA) introduced a requirement in England for all businesses to separate food waste from other waste streams for at least weekly collection. This was part of the "Simpler Recycling" initiative [15]. Expanding such efforts to include support for canning programmes - like funding "Master Food Preserver" courses - could empower more people to safely preserve seasonal produce [6].
On the industry side, companies can make a difference by investing in lightweighting technology to reduce the environmental impact of metal packaging. For example, modern steel food cans are now 46% lighter than they were 30 years ago, with some weighing as little as 41 grams [14].
In summer 2023, Zero Waste Scotland launched the "CAN-paign" with celebrity chef Julie Lin, encouraging festival-goers to embrace tinned food as a way to cut waste and save money [16][17].
"Our CAN-paign sets out to dispel some of the misconceptions around canned and highlight tinned food as a winner when it comes to budget-friendly ways to cut household food waste" – Iain Gulland, Chief Executive of Zero Waste Scotland [17]
Efforts like these, along with incorporating canned goods into the UK's food waste reduction targets, could tackle the 41% of household food waste caused by fresh food spoiling before it's used [16].
Conclusion
Canning offers a practical way to tackle food waste while also addressing climate challenges. By preserving surplus produce at its freshest - ideally within 6 to 12 hours of harvest - it transforms perishable items into long-lasting, shelf-stable goods. This approach directly addresses the staggering statistic that 25–30% of all food produced is wasted, contributing to 8–10% of global greenhouse gas emissions [1][10][18]. In addition, canning helps extend the life of seasonal produce that might otherwise spoil [10][5]. In the UK alone, where 23% of food system emissions stem from food waste, methods like canning can make a noticeable difference [1].
"Canning can be a high impact intervention... to stabilise prices, increase market reach and better access to year round nutritious foods." – Neha Kumari and Priyadarshani P. Mohapatra, Department of Food Science and Nutrition [18]
This quote underscores the value of canning not only for households but also for markets, enabling better access to nutritious food throughout the year. Whether you're preserving surplus from your garden or managing excess produce, canning empowers you to reduce waste in your own home. Just remember to consume your preserved goods within a year to enjoy their nutritional benefits and minimise your environmental impact [10][6].
From individual households to larger-scale industry efforts, canning stands out as a practical and scalable way to stabilise food systems, lower emissions, and ensure resources aren’t wasted. By making canning a regular part of your routine, you contribute to a more efficient and responsible food system - one jar at a time.
FAQs
How does canning help reduce food waste and lower emissions?
Canning is an effective way to cut down on food waste by preserving extra produce and prolonging the shelf life of seasonal items. This process helps prevent food from spoiling, ensuring that perfectly edible items don’t end up discarded.
On top of that, recycling metal cans plays a big part in reducing waste. It not only keeps thousands of tonnes of solid waste out of landfills but also lowers emissions tied to producing, transporting, and disposing of unused food. By maximising the use of available resources, canning supports a more efficient and responsible food system.
How does using canned food help the environment?
Canned food offers a practical solution for cutting down on food waste by keeping surplus produce fresh and extending the availability of seasonal items. By preventing food from going bad, it helps reduce the massive amounts of waste that would otherwise end up in landfills, where it contributes to greenhouse gas emissions. In the UK, food waste is responsible for about 23% of emissions, so this simple choice can have a noticeable environmental impact.
What’s more, the sturdy and recyclable nature of cans adds another layer of eco-friendliness. This supports a circular economy by ensuring materials are reused, rather than discarded. Opting for canned food isn’t just a convenient choice - it’s a small but meaningful way to help protect the planet.
How can households easily start canning to reduce food waste?
Canning is a brilliant way to preserve the flavours of the season, cut down on waste, and save a fair bit of money. To ease into the habit, try setting aside a regular day each month for your canning sessions - perhaps when your garden is overflowing with produce or when local markets are bursting with fresh fruits and vegetables. A little planning can make it a seamless part of your routine.
Before you begin, make sure you’ve got the essentials: proper jars and lids, a boiling-water or pressure canner (depending on what you’re preserving), and a clean, organised workspace. Start by thoroughly washing your produce, trimming it as needed, and, for low-acid foods like vegetables, ensuring the acidity levels are correct. Stick to the recommended canning method for each type of food to maintain safety and quality.
After processing, label each jar with its contents and the date (e.g., "Strawberry Jam – 20 January 2026") and store them in a cool, dark spot. By making canning part of your routine, you’ll enjoy seasonal flavours all year long, waste less food, and even save up to half the cost of shop-bought canned goods.
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