Category Archives: small block

Fun for the whole family with a household waste audit

The waste audit on our path to an zero-emissions home revealed a grand total of 50kg of annual emissions and some ways to reduce it. Here’s how to do a waste audit, and what we found.

Why waste?

The average Australian generates about 1,200 kg of waste each year. The average emissions from municipal (household) waste, is approximately 1.4 times the weight of the waste, meaning that average Australians emit about 1,680 kg of CO2e  each year. Total emissions from Australian solid waste are about 23,000,ooo tonnes per year, or  3.8% of Australia’s total emissions footprint in 2014-5. So emissions from waste are worth worrying about.

Emissions from waste are mainly the result of organic substances, like food scraps and paper, breaking down in landfills. When this happens underground in a landfill, it forms methane, which has about 25 times the global warming potential of carbon dioxide.

Most rubbish bins contain lots of organic waste. Organics are about 65% of household waste when councils do not collect garden and park waste, and about 60% when they do.

My council does collect garden and park waste, but I don’t use the service. Instead I give (nearly) all of my food scraps to the chooks and compost (most of) the rest. We make very good use of the council recycling bin, so our landfill waste is significantly less than would be without that service. So I was expecting my waste emissions to be lower than the average. I did a waste audit to check.

Here’s how to do a waste audit, and what we found.

My household waste audit

Equipment

  • A unit of waste – we used one average week’s waste, collected from all household bins.
  • A tarp, or enclosed area to sort the waste – we used a kids play-pen.
  • A set of scales for weighing the waste.
  • Buckets to hold waste.
  • Tongs, so you don’t have to touch it.
  • Gloves, for the bits you do have to touch.

Method

Decide on your categories.

If you are trying to work out whether the waste is going in the right bins, your categories need to match the bins, eg:

  • landfill waste,
  • recycling,
  • organic.

If you are working on a carbon footprint, then your categories need to match the groups of wastes with different emissions factors, or global warming potentials. This only applies to the organic component and according to the Australian National Greenhouse Accounts Factors (Table 41), includes:

  • food,
  • paper and cardboard,
  • garden and green,
  • wood,
  • textiles,
  • sludge,
  • nappies,
  • rubber and leather, and
  • inert waste.

I was interested both in whether householders were using the right bins, and also in calculating the greenhouse emissions. So I used every relevant organic waste category, plus ‘landfill waste’, which is essentially the waste that should have been in the rubbish bin, because there wasn’t another option. I also added two other categories of interest. They were:

  • paper towels – which I use quite a bit to mop up organic kitchen waste which I don’t want to flush down the sink, as it fills up my septic tank with sludge, and
  • monstrous hybrids – which are an infuriatingly difficult category made up of things that could be recycled, if only they weren’t joined together with things that can’t be.

Sort your waste

Tip the waste into the sorting area, and get to work with the tongs. Put all of the waste into its waste category.

Then, fill a bucket with waste from just one category and weigh it. First you’ll need to zero the scales so that you weight the waste, not the bucket. If you are thinking about bin sizes, you need to estimate the volume, or size of the waste, but for carbon accounting, just the weight will do.

Record the results

Here are the results from my household’s weekly waste audit.

 Category kg
hand towels 0.21
Co-mingled recyclables 0.1
Inert waste 0.58
Monstrous hybrids 0.05
Food 0.19
 Total 1.13

Multiply by 52 to get an annual total.

  Weekly Annually
 Category kg  kg
hand towels 0.21 10.92
Co-mingled recyclables 0.1 5.2
Inert waste 0.58 30.16
Monstrous hybrids 0.05 2.6
Food 0.19 9.88
 Total 1.13 58.76

Calculate the greenhouse gas emissions

To calculate the emissions, you need the emissions factors for each type of waste. These are in table 41 of the Australian National Greenhouse Accounts Factors, which is regularly updated, so get the current version. This gives a multiplier for the weight of each type of waste. To work out emissions, all you have to do is multiply the weight of each organic waste type by the relevant factor, like this.

Weekly Annually Factor Emissions
Category kg kg Multiply by weight kg CO2e
hand towels 0.21 10.9 2.9 31.7
Co-mingled recyclables 0.1 5.2 0 0
Inert waste 0.58 30.2 0 0
Monstrous hybrids 0.05 2.6 0 0
Food 0.19 9.9 1.9 18.78
Total 1.13 58.76   50.44

How did we go?

This gives me a total of just over 50 kg of emissions from waste each year. My household is about 3 people, so that’s only about one per cent of the emissions of an average three-person household (3 x 1680= 5,040).

Frankly, I’m amazed it could be so low, and so I’ll use some other blog posts to look into how I’m keeping it down. Most of it seems to be the chooks, and the aerobic composting, but we’ll see.

Can we improve?

Despite the emissions being so low, there are several things I could do to reduce even further. I could:

  • either stop using hand towel or put it in the council’s green bin. This would take out 31.7kg per year of CO2e emissions.
  • be more rigorous about composting all organic waste or giving it to the chooks. The food waste still in the mix was generally uneaten cat food, or meat bones. These are tough wastes to get rid of, since bones don’t break down, and I don’t like to feed cat food to the chooks, because who knows what’s really in it. However if I could solve this, it would cut out the other 18.8 kg of organic waste. Again, some of it could go in the council green bin.

Why not check your own waste

Inspired? Have a go at doing your own waste audit. Its fun for the whole family. Or perhaps not. As I said in another post, the household 13yo found it totally gross (there were some maggots on the food waste).

Myrle pouring rubbish for waste audit

If you do a waste audit, tell us what you found.

Steps on a carbon-neutral journey

How will I know that my home is carbon neutral? How will others believe me? The first steps are working out what to measure, and how to measure it. This post explains how that’s done.  It’s a little bit dry, so to keep you interested, here’s a snapshot of the next step which was the waste audit, described by the household 13yo as ‘totally gross’.

Myrle pouring rubbish for waste audit

The National Carbon Off-set Standard (NCOS) tells us to do a life cycle analysis (LCA) of the greenhouse gas emissions associated with home. That means working out a ‘cradle to grave’ assessment of all greenhouse gas emissions involved in running a household. The NCOS points us to the International Standard for Environmental Management – Life cycle assessment – Principles and Framework IS014040 identifies four phases for an LCA. Here’s how it looks for my house.

flow diagram for carbon LCA

There are some general standards, and some choices about the scope of a greenhouse gas inventory. These are well established for businesses and products, and they can also be applied to a home. For instance, the Scope 1 emissions from my diagram are really a must. Those are the direct emissions from gas heating and fires, and anything else burned or decomposing at a site. Strangely, human breathing is not included in inventories, even though animal farts may be.

pre-winter solstice bonfire 2015

Emissions from electricity used in a building are also a must in the inventory. But you don’t have to include the full fuel cycle emissions from electricity, like transmission losses from the poles, wires, and the times when high voltage loads are transformed to lower voltages. I’ve chosen to include the full fuel cycle. The interpretation stage gives me a chance to change my mind about this if it’s not working out. Similarly, I’d love to include the emissions associated with the stuff we buy for my home. I would, but the data gathering and calculations are way too complex.

The reason that we can exclude these ‘scope 3’ emissions is that they are all included in the inventories being done by other people or businesses. For instance, I’ll be counting emissions from air travel, even though airlines are required to record and report all of those emissions under Australia’s National Greenhouse and Energy Reporting Scheme.

Keep your eye out for the next post, on my home waste audit. That’s when we’ll start to see how my emissions stack up, and what I can do to reduce them.

Towards a carbon neutral home

In Paris, 2015, the Council of Parties reached international agreement that urgent action is needed to prevent climate change. Then February 2016 broke all the records for breaking global warming records. More needs to be done and I can do some of it myself, starting at home.

New Commitment for 2016: Make my home carbon-neutral.

I’ll aim for my home-life to be healthy, comfortable and affordable, but not to contribute to global warming. I’ll also record the details in this blog, and encourage other households to join in.

The plan is to systematically:

  • measure my carbon footprint,
  • look for ways to reduce emissions,
  • off-set whatever remains,
  • continue assessing and reporting so I can continue the journey, and maybe even become carbon negative.

The Australian National Carbon Offset Standard shows these steps together like this.

So what does it mean to be carbon neutral?

We humans are emitting greenhouse gases into the atmosphere faster than they can be absorbed back into the earth. As a result, more heat is trapped within the atmosphere than previously, and global temperatures are rising. This is happening even though some people don’t understand, or disagree with the science.

(If you are one of those climate change denialists, there’s no point me arguing with you, and you won’t be interested in this blog, so kindly head off and put your head in the sand somewhere else).

People who measure and reduce the greenhouse effect have worked out an accounting system to keep track of emissions. The basic idea is to get all of the emissions in the same units. Lots of different gases contribute to global warming. Each gas has a different impact, or global warming potential. A tonne of methane (CH4) for instance, causes about 25 times as much global warming as a tonne of carbon dioxide (CO2). And a tonne of sulphur hexafluoride (SF6) has about 23,900 times as great an impact. Because CO2 is both the most common greenhouse gas, and also has the smallest impact per unit, we simplify things, by using CO2 as the reference point. All we have to do is to convert all emissions to their carbon dioxide equivalent (CO2e), and we can sum the totals together.

Carbon Neutral Standard diagram

Being carbon neutral means minimising your emissions, then balancing any that remain with an equal amount sequestered or off-set. Basically, you absorb as much as you emit.

In the next few blogs, I’m going to measure the emissions my household has from:

  • waste,
  • electricity,
  • other energy sources,
  • transport,
  • other sources.

Wish me luck and come along for the ride.

The hot dirt on compost

By Su Wild-River

It’s well known that compost generates heat. Clever people even heat their houses, run cookstoves and cars off compost. Here’s a little look at a humble backyard compost system through the lense of a thermal imaging camera.

A thermal imaging camera is really a heat sensor, not a camera which shows what you see with your eyes. In these photos, the hottest areas are shown in white, and a rainbow spectrum going through red, to yellow, green and finally blue, show colder areas.

The photographs were taken on a cool autumn morning, with an ambient temperature around 14 degrees Celsius (about 57 Fahrenheit). The yellow glowing thing is a ‘compost dalek’, or plastic drum with air vents at the top, and compost inside.

Its interesting to see in the first pair of photos, that the water-filled pot at the front, and the two ceramic pieces behind are the coolest spots around. These are the high thermal mass areas of the photographs, and I was surprised at first to see that they were so cold, as I usually think of thermal mass as warm. Of course the main feature of thermal mass is not that it stays warm, but that it moderates temperature changes. Large thermal mass elements, like water tanks insulated slabs change temperature so slowly that they stay around the long-term average ambient temperature.

Compost by Kath McCann. Photos by Su Wild-River

Compost by Kath McCann. Photos by Su Wild-River

The outside of the compost dalek registers a temperature of around 16.5 degrees Celsius. It is much warmer than everything around it, and only the vents are colder.

Looking inside without turning the compost gives us a look at even higher temperatures. The hottest parts here are about 20 degrees Celsius. They are the deeper parts of the compost, so we dug a bit further.

Compost by Kath McCann, Photos by Su Wild-River

Compost by Kath McCann, Photos by Su Wild-River

Only an inch or so down, the hottest temperature was 26.4 degrees Celsius. This is more than 10 degrees above the background temperature.

Compost by Kath McCann, Photos by Su Wild-River

Compost by Kath McCann, Photos by Su Wild-River

Now this compost is owned by Kath McCann, a keen gardener, and a good composter, but not someone who is using the stuff to heat her house. It seems as if even humble compost could make enough heat to warm us up, if only we plan and use it wisely.

So there you go. Compost really is warm. How could you be using yours?

Food security and the vegetable decathlon

By Su Wild-River

This post was first published at http://nofunnybusiness.net/2014/03/food-security-and-the-vegetable-decathlon/

Scientists are tackling global food insecurity in a range of ways. They are researching crop narrowing, analysing hunger and health, connecting food risks to climate change, debating genetic engineering solutions and making a Doomsday Vault. As a scientist, I’m doing the heirloom vegetable decathlon.

Khoury et al’s recent paper on the “increasing homogeneity in global food supplies and the implications for food security” quantifies the global shift away from highly diverse food sources 50 years ago to a much smaller set of globally important, energy-dense foods now. The winners in the food supply race include wheat, rice, soybeans, palm and sunflower oil, potatoes and sugar and we rely ever more heavily on them. Wheat for example is now a key food in more than 97 % of countries. These narrow crop types have displaced coconut, cassava, sorghum, millet, rye and sweet potato and many more from traditional and national diets, being cheaper, easier to grow and quicker to prepare.

On the positive side, easy-to-grow, energy-dense foods have helped feed the world’s hungry people. The United Nations Food and Agriculture Organisation estimates that total number of people who are not hungry increased from 4,370 million people in 1990-2 to 6,225 million in 2012.

Medical scientists are examining the risks. One risk is to our health. People who eat mainly energy-dense foods are at risk of obesity, heart disease and diabetes.

Crop diseases and their solutions have attracted scientific research. The southern corn leaf corn blight of 1972 and the Irish potato famine of 1846 show that crops with limited genetic variability can be highly susceptible to new disease outbreaks. Agricultural scientists are warning that with billions of people now relying on fewer food crops, new disease outbreaks could make us hungry. Crop heterogeneity is a possible solution and works by maintaining a rich gene pool through strategic interbreeding of common crops with wild cultivars. Genetic engineers are also quick to offer solutions, and transgenic plants are being developed with resistance to viruses, fungi, bacteria and nematodes. But few commercial GM cultivars are available in the short-term, and ecologists caution that over time they may bring new threats such as superweeds and toxic pesticides. GM crops they say, are at best a contentious solution to food insecurity.

But in addition to problems identified by food and health scientists, broader issues are at stake. Climate change is widely understood as an emerging, serious threat to food security. The European heatwave in 2003 and American heatwave in 2012 both reduced crop production by up to 30 % and sent prices soaring. Scientists have considered whether extra carbon dioxide and warmth could have positive food production consequences, but in 2013-4 the International Panel on Climate Change reported that negative impacts have been more common.

A Doomsday Vault in the Arctic Circle is an engineering solution to avert the risks of narrowing crop diversity. The vault now holds more than 800,000 seed samples as an “ultimate insurance policy for the world’s food supply”.

I’m doing my bit for crop diversity too. Gardening after all, is cheaper than the psychological interventions needed to cope with hunger, and you get tomatoes. And as well as tomatoes, potatoes, corn and the other common crops I grow rarer treats like medlars, mizuna, okra, kale, rhubarb and Jerusalem artichokes. I save seeds too, and this has led me to favourheirloom plants to enjoy and maintain old cultivars that breed true.

And why is this the vegetable decathlon? Because I’m after the elusive first prize in the coveted “Group of Ten Vegetables” category at my local Braidwood Show. Second again this year.

How are you applying science in your kitchen and garden?

From the Sun to my Screens

By Su Wild-River

This post was first published at: http://nofunnybusiness.net/2013/12/from-the-sun-to-my-screens/

I recently completed a Massive On-Line Open Course (MOOC) called “Dynamic Earth” through the University of Toronto. And in case you are wondering whether science can be taught through MOOCs, consistent with the pedagogical analysis presented by MOOC providers, I’m giving you a glimpse into MOOC world here.

The course’s ‘peer reviewed assignment’ was a 300 word essay anonymously assessed by three other randomly selected students who have also received a marking rubric and examples of papers of varying quality that have already been graded by professors.

The topic for this assessment was to trace the likely path from the device on which we view MOOC study material, back to the original astronomical source of energy – ie some form of solar energy. Is this science? Is it science communication?

Here is my response to the assignment topic – from the Sun to my Screens

“Fossil fuels are an input to all of the devices that feed MOOC materials into my brain. Those devices include a computer at The Australian National University (ANU), a home computer, and iPad.

My computer at The Australian National University (ANU) and my home electricity system are connected to the Eastern Australian electricity grid (EAEG), which sources mostly coal-fired electricity. The coal is burned to release heat which boils water to turn turbines and generate electricity, which is then transported through the grid to my computer. The coal issourced from plants that grew 200-300 million years ago and used solar energy for photosynthesis, converting carbon dioxide to cellulose. They then compressed into coal due to overlying sedimentation in a process fuelled by solar driven wind and water systems. Burning coal for electricity is inefficient and releases terrestrial carbon dioxide back into the atmosphere, unbalancing the earth’s dynamic atmospheric system and causing dangerous global warming.

My devices are also powered by a small amount of hydroelectricity and wind energy with fewer damaging impacts. The wind occurs because the sun warms the Earth’s surface, particularly at the equator. The Earth’s rotation and Coriolis Effect drive a pattern of wind across the world. Rain captured in the Snowy Mountains hydroelectric scheme falls there because low pressure systems are blown across Australia by Southern Hemisphere Westerlies. Water evaporates from the Southern and Pacific oceans and is uplifted in the low pressure systems, cooling and causing precipitation as the lows spiral clockwise across the Snowy Mountain Range. The rain is stored in dams high in the landscape, and then released under gravitational pressure to turn turbines that generate hydroelectricity. The Westerly winds also power turbines within the EAEG, generating electricity from wind.

At home I use a desktop computer, and charge my iPad to access this MOOC. Most of that energy comes from a solar array on my roof. Solar electricity is a more sustainable alternative to coal-fired power because it uses solar radiation directly from the sun, and there is no additional atmospheric pollution once the systems are installed.

I also use by brain to access this MOOC. The final energy pathway is the food I eat to power my brain and body. I grow about a quarter of my own food, mostly using the glycogen and glucose produced in my body by my digestion of that same food as the power source. The other half of my food is shop-bought, and I try to keep the food miles and other fossil fuel energy inputs down by buying fresh and local, with minimal packaging. The plants that I eat use photosynthesis to transform sunlight, nutrients and water into delicious cellulose. My brain is digesting the course material, and instructing me to work at home, using my solar energy systems.”

I received 26 out of 27 from my peer reviewers – so I was pretty happy with that. I also received the comment “You’re not a student, are you? That is the best and most extraordinary answer I have read so far. Thank you and God bless!” which I found rather enchanting.

I was however, somewhat disturbed when it came to my training in how to mark others’ assignments. I was given three assignments to mark as a test run – to calibrate my marks with those of the professors. The first one received 8/9 from me, but only 3/9 from the professors. The MOOC program instructed me to review the rubric. The second was better. I gave it 3, and they gave it 2 but I was still asked to review the rubric. I thought the third example was logically flawed and gave it 2, while the professors gave it 9. The next screen congratulated me on completing my training and started directing me to mark others’ work.

I enjoyed the marking process although I was nervous about the quality of my marking. I marked one from a remote area of Russia, and was fascinated to read about the landscape, isolation and its impacts on energy opportunities, with nuclear and coal seeming the only realistic options. It reinforced the message that those of us with green-energy leanings in Australia parrot out all the time – there’s so much energy here that we have no real excuse to burn all of this coal.

What energy are you using to access this blog, and what are the alternative pathways from the sun to your screen?energy-transformations1-300x174

Writing plain English science into legislation; or Compost Eats Methane

By Su Wild-River

This post was first published at: http://nofunnybusiness.net/2013/12/writing-plain-english-science-into-legislation-or-compost-eats-methane/

Both legislators and scientists can struggle to communicate our work effectively in plain English. How much harder is it when we try to encapsulate science in a law? I’m facing this challenge at the moment, drafting a Carbon Farming Initiative methodology which if accepted, will form a regulation under the Carbon Credits (Carbon Farming Initiative) Act 2011.

The Carbon Farming Initiative (CFI) was introduced by Australia’s previous Labor Government, and is one element of Australia’s climate change mitigation framework that issupported by the current Coalition government. The program allows farmers and land managers to earn carbon credits for reducing or avoiding greenhouse gas emissions. CFI methodologies establish the rules for calculating credits confirming that they are genuine, permanent and additional to business as usual. To achieve this, the methodologies must beclear, unambiguous, complete and precise.

The methodology I’m working on is called Passive Landfill Gas Drainage and Biofiltration. In plain English, this means putting compost on landfills, because compost eats methane.

This methodology is in part a eulogy to much-loved environmental professional Mark Ricketts who died suddenly in 2011. Shortly before his death, Mark was advising me and my students on a project to estimate the carbon emissions and reductions from landfills when he told me to consider compost, and then earned giggles with stories of the insatiable hunger of compost greeblies and the yumminess of smelly gas.

I had previously worked alongside Mark while he was drafting the Queensland Environmental Protection Act 1994. I watched his optimistic daily trips to the parliamentary draftsman and his exasperated return to our office as he tirelessly negotiated for each sentence to be as simple and readable as possible. The result of his work is a plain English law that encapsulates the precautionary principle, ecologically sustainable development and other complex concepts based in science.

Drawing inspiration from Mark, my team’s CFI proposal was to design a simple, practical method which used robust science, while being easily understood by the hundreds of operators of small local landfills across Australia. Many of these good folk lack the time and capacity to read complicated laws, engineering equations or to establish scientific procedures for their monitoring and evaluation. But they can pick a winner and follow procedures.

Our methodology needs to be consistent with all related national and international methods, so I have read and reviewed hundreds of scientific papers on compost and landfills and the calculation of carbon emission reductions. Most emission reduction methodologies explain themselves through symbols and equations with the most relevant one having five solid pages of such equations, interspersed by just a few sentences for those of us without maths as a first language (pp2-6). Here’s an example:

Excerpt from CDMIIIAX

In contrast, our equations look like this:

 Net greenhouse gas abatement = quantity of methane that is oxidised by the biofilter – baseline emissions – project emissions.

Other strategies for keeping it simple include minimising the number of measurements and using simple, cheap and readily available equipment.

So far progress is good, and our focus on practicality and clarity is well received by the government and stakeholders alike. It was hugely satisfying when the non-technical member of our Technical Working Group smiled saying he found our draft methodology very readable.

Assuming the methodology gets approved, the next step will be to find project proponents. Unfortunately, this step is less likely to succeed. Australia’s initial carbon credit value of $23 per tonne meant that projects could have pay-backs in under seven years, and reap annual profits thereafter. A direct action approach delivering a carbon price of – say $8 would take over 50 years to pay back. The most likely outlook is an elegant methodology that will fail to feed any compost.

Am I the only one disappointed?

Fighting the Waspocalypse

dead wasps

Wasp nest plugged with petrol-soaked rag, displaying dead wasps on the doorstep. Intervention plus 1 night. Photo by Su Wild-River

By Su Wild-River

A version of this story was first published at http://www.braidwoodtimes.com.au/story/3009887/fighting-the-waspocalypse/

My home town is under attack. Yellow-and-black striped European Wasps are zooming around our district, hanging around food and chasing us indoors. Thankfully I haven’t been on their pointy end, although my son has twice. Individual wasps can sting several times, each time worse than a bee. They can also swarm and deliver many stings at once.

The wasps are attracted to sweet food and meat, so cleaning up and sealing rubbish will discourage them. The wasps will fly straight from their food to a nest, making the nests fairly easy to find.

Nests are usually small holes in the ground, about 4-8cm wide. Nests can house up to 100,000 individuals which stream in and out all day.  Stay well back because if a nest is threatened, the wasps release a chemical which triggers the colony to attack the threat.

Maybe it was the moist summer, and perhaps the great apple season which has left fruit rotting around the trees. Whatever the reason, there are more of these wasps now than in the past.  The local pest controller says he previously only had 1-2 call-outs for nest removals in a year, but he’s getting 3-4 a week at the moment. One of our local rural supply shops got 5 cans of wasp spray in last Friday and sold out in a single day.

The pest controller says we need to keep on the lookout for nests. If we find one, the best and safest option is to find the local pest controller in the Community Directory and arrange for him to destroy the nest. Autumn is a critical time since now the queens and laying eggs for the next generation of queens. Every nest we kill now could reduce the problem significantly for next year.

The Museum of Victoria publishes tips for “Do it yourself European wasp extermination”, and like me, takes no responsibility for injuries incurred using the information. But I’ve destroyed some nests, and talked to many others around town who have done it too, so here’s what I’ve learned.

* Don’t risk it if you are allergic to wasp stings,

* Make sure someone knows where you are and what you are doing.

 * Treat the nest at night when activity is low,

* Wear loose clothes and fully cover your body, head, eyes etc,

* Put red cellophane over a torch, because they can’t see red light, and don’t alert them by shining it right at the hole,

Locals are having success with several different treatments. The pest controllers are licensed to use a high strength powder which will knock out a nest in one go. Other premethrin, propoxur or carbaryl dusts are available, although not in Braidwood. Both local rural suppliers carry propellant cans of wasp killer. Petrol is another option, and though the experts advice is that it doesn’t work well, it did the trick on my nests. Either pour 1.5L down a nest on two consecutive nights, or soak a rag in petrol and plug the hole with it. The fumes kill the wasps, so don’t light the petrol. Check treated nests in the following days, and be prepared to retreat to finish the job.

The Department of Primary Industries in my home state of New South Wales also has a fact sheet with useful information.

10 beginners tips for practical food preserving

By Su Wild-River

Have you ever wished you were ‘one of those people’ with colourful cupboards full of bottled tomatoes, jams, pickles and fruits? Are you scared off by advice on the hazards of preserving? Here are some tips to make the transition so that you can make all the preserves you desire without fuss or stress.

But first, let us consider the costs and benefits of preserving food.

1) The only equipment you need is a saucepan and some metal-lidded jars

The professionals use custom-made products like Vacola and Kilna and perhaps one day you will too. But to make a start, all you need is some metal-lidded jars. So the next time you are in the supermarket, choose products in metal lidded jars. When you have used the product, clean the jar carefully and store it for your preserves. Build up your collection more quickly by asking friends to do it too.

Preserving food in Autumn for Winter and Spring.

Preserving food in Autumn for Winter and Spring.

2) You don’t have to grow it to bottle it

My entire fruit crop was taken out last year by a severe, late frost, but that didn’t stop me from making preserves. Buy bulk, in season, direct from farmers if you are lucky enough to have a farmers’ market or street stall in your area. Although it doesn’t have the same inner glow as food you grew yourself, it’s still fresh, probably cheap, and certainly has low food miles compared with supermarket fruit and vegetables.

3) Learn the basics

There are many wonderful recipes on the web and in books, and I won’t repeat them here. But its helpful to know the basic options available to you. The essence of preserving is to slow the decay of real food so that you can eat it long after it was fresh. This is achieved by removing the elements that make it decay and also by adding other ingredients that help keep it edible longer. The main elements that cause food to decay are moisture, air, bacteria, light and heat. Some common ingredients that help keep food longer are salt, sugar, acid (vinegar).

Here are some of the main options:

  • Simple bottling: Just as the name suggests, this is the easiest option and a good way to start. It generally involves just one type of fruit or vegetable (eg peaches, plums, apricots, tomatoes), optionally with a preserving additive. This method works by removing bacteria and air and is achieved by boiling the produce until it is well cooked, and bottling it while it is very hot. Avoid bacteria by using clean, sterilised jars. Avoid air by filling them to the top and banging or pushing out as many bubbles as possible. Because the jar and produce are hot when the lid is sealed, the small remaining air pocket forms a vacuum, and this essentially removes the air. You can easily check that there is a vacuum, because the lid will ‘suck in’ when the jar is cool. Some of the professional bottles allow you to cook food in the jars, and seal the lids when you are done. The big advantages is that the cooking process kills all bacteria in the jar, ensuring that the bottle is sterilised. I choose not to do this with my gathered metal-lidded-jars, because I’m not sure that the sealant will cope.
  • Bottle mixtures: Bottled mixtures include jams, pickles and sauces. All of the same principles apply as with simple bottling, so jars need to be clean, sterilised and full. Recipes for bottled mixtures include preserving ingredients like sugar (for sweet things), salt, vinegar, mustard seeds etc for savoury, along with a range of flavours.
  • Smoking and drying: These methods work by removing the water from within the cells of food. The food will last longer if it is kept dry, cool and dark and the more you achieve all three of these, the longer it lasts. So a smoked trout will last a very long time (years?), while one in the cupboard may last several days.
  • Freezing: This method works by cooling food down to avoid decay. Its very common for vegetables like peas, beans and corn. Its often good to boil before freezing, partly to kill any bacteria, partly because it makes the colour brighter, and also because they retain their fresh flavours and shape better that way.

4) Get on a roll

Preserving doesn’t have to be a big event. I have learned to bottle up tomatoes every time I have enough to fill a saucepan. That’s a few times a week in the mid-season. I just cut them up and put them in a pot with a little salt when I’m starting to make dinner, and then leave them cooking until bed-time, because the longer you cook them the better they are. At bed-time, I take them off the boil and ladle them into clean jars (see ‘clean your jars’ below) and presto – preserved tomatoes for winter.

You can get on a roll most easily for simple preserves with one main ingredient, but once you master jams, pickles and other preserves, you’ll find you can do it with them too. A friend of mine regularly cooks up one or two jars of raspberry jam.

5) Treat it as an adventure

Your preserves don’t have to win awards, or be textbook perfect every time. The beauty of practical preserving is that every batch has its own personality. My very best jam was the ‘burnt heatwave apricot jam’ of 2013, which was burnt on the stove, not by the heatwave. I’m down to the last jar now and everyone is mourning it. But my ‘runny apricot jam’ from 2012 was great as a topping for pies, and the chooks eventually enjoyed ‘crystallised apricot jam’ of 2011.

The thing is, we are not preserving food to make products like the mass produced stuff of supermarkets. We do it for the love of good, local food that contains delight as much as nutritional value.

6) Label your preserves

Since each batch will be a bit different, you probably get the message its a good idea to put labels on your preserves stating the date they were made, and naming any special features. I don’t bother with the tomatoes, as I end up with so many jars each season, all pretty much the same. But jams are individuals, and so are pickles. Make your last, half-filled jar the taster, and name the batch a few days after cooking, once you have tasted and evaluated your results.

7) Look after your food needs

Preserving your own is the perfect way to avoid the foods you can’t eat, while favouring those you can. Last year a health practitioner advised me to slow down on the sugar….. just at the start of the stone fruit season. I wondered how I could preserve the abundant local peaches without sugar. I did some research and it turns out that the trick to making preserves without sugar is….. don’t add sugar. The peaches aren’t as sweet as they would have been with sugar, and they are not as brightly coloured. Apparently they won’t last as long either, but luckily I know how to deal with that (see ‘check your preserves before eating them’ below).

8) Clean your jars

If your jars have any bacteria on them, the preserves will go off very quickly. So make sure your preserves go in spotlessly clean jars.

Most importantly, you need to clean them well before putting them away for storage, since that’s the easiest time to clean them. The trick is to check that all of the ‘bits’ are gone. Check the inside of the lid, and all the way to the bottom corners, and be meticulous. If you can see, feel or smell anything that isn’t part of the jar then the jar isn’t clean.

Sterilise the jars again before you put in the food. A simple approach is to collect up the jars you plan to put your food into while your preserves are cooking, then boil the jug and pour boiling water into both jars and lids. Wear some rubber gloves and be careful to avoid burning, swirl the water around and then discard it into the sink. Be careful not to touch the inside of the lids or jars after this sterilisation process, and also to keep the rims up so that they don’t touch the benches. The remaining water will evaporate, and you’ll have a sterilised jar.

9) Keep them in the dark

Yes, they are beautiful. And they are a source of pride. But if you have them on display the light, and variable temperature within a living room will cause the food to decay faster. Better to keep them in a dark cool cupboard.

10) Check your preserves before eating them

OK, so there is a risk that your food may go off before you open the jar to eat it. This happens every so often, for the same reason that shop-bought preserves can go off. Maybe you left them too long and the few bacteria that were alive in the bottle grew babies. Whatever happened, the thing to remember is that it is within your power to make it safe.

When you first remove your preserve from storage, check it thoroughly. Can you see any mould? Has the lid popped out? Is there a discharge from around the seal of the container? When you open it, continue to check for mould, but also assess the smell. In particular, take a good, big sniff of it the moment you open it up. It should smell pretty well the same as when you put it away for storage – that is, delicious and totally edible. If there is a bad smell, or a release of air from a jar (like when you open a carbonated drink like beer or soft-drink), then its probably no good and to be on the safe side, you should throw it away and reach for another jar. I will occasionally still eat produce that had a tiny amount of mould on the top, but only ever after I have scraped off a good inch, and then repeated the sniff test and tasted a bit as well.

The thing is that one of the definitions of REAL food is that it CAN go off. Any food that doesn’t go off needs serious questioning about whether indeed it actually is food. So the mere fact that your preserves can, and sometimes do go off is a source of celebration, not distrust. Use your senses and your smarts to decide whether to eat what you have preserved, and you will be able to keep yourself, your friends and your family safe and healthy.