How can you make fruits and vegetables last longer? Something I haven't done yet as a 22-year-old. This is particularly useful here in Norway, because the cold season is long here in Volda and a lot of fruits and vegetables don't grow all year round. Of course, in the age of modern supermarkets, this isn’t as relevant anymore. However, fruits and vegetables are cheaper when in season, so knowing how to preserve them allows you to save money. In 2015, 45% of the fruits and vegetables produced were wasted (FAO,2015). Susan Hill (2025), an extension agent for food safety and quality at the Auburn University, said, that food preservation techniques help to reduce food waste, extend food shelf life and reduce food insecurities. In 2024, 74.5 kg of food per person were still being wasted in my home country Germany (BMLEH,2025).
Jars must be disinfected before use. To do this, the jars must be cleaned thoroughly, labels and adhesive residue removed, and then disinfected in the oven at 100°C. Alternatively, the jars can also be boiled. The lids of the jars often cannot be put in the oven due to a plastic seal, but are boiled instead. To do this, simply place the lids in a pot of water and bring to a boil. You can simply leave the jars and lids to disinfect until the product is ready. The jars should be in the oven for at least 15 minutes.
Glasses for disinfecting in the oven Photo: Mélanie Lang
Pickled pears
Ingredients:
2 pears
300g sugar
500ml water
I used the recipe for canned pears from Kari Ryslett, one of my teachers here. It was in the recipe booklet we received in class (August, 2025).
First, I started by preparing the pears for canning. To do this, I peeled the pears and removed the cores. Then I cut the pears into eighths so that they would fit better in my jar.
The pears after peeling and cutting Photo: Stine Koopmann
The preservation liquid is very easy to make. Boil sugar and water together until the sugar has dissolved. Then cook the pears in the sugar and water mixture until they are soft when pierced with a fork. However, they should not become too soft. In my case, this took a good 5 minutes.
Then transfer the pears to the disinfected jar and fill the jar with the sugar water until there is about 2 mm of space to the rim. A funnel that fits well on the jar is very useful for this. Then set the jar aside to cool. It should vacuum seal itself and be preserved.
Pears in sugar sauce, ready for sealing Photo: Stine Koopmann
Jam:
Ingredients:
400g blueberries
200g sugar -> too much for my taste, I would recommend something between 160-180g of sugar
10g gelling agent (Jam Sylte Pulver) -> in my current attempt, I used 22g, which was due to a calculation error and was clearly too much
I used a German recipe from the baking blog “einfach backen“ (Siggi, n.d). I adjusted it a bit to match my amount of blueberries.
First, I washed the blueberries and then brought them to a boil in a pot. Then I added the gelling agent and let it boil for 2 minutes. After that, I stirred in the sugar (150-200g) and waited briefly until the sugar had dissolved. Before transferring the jam, I pureed it with a hand blender to ensure there were no pieces left in the jam.
All the products I used for my jam. Blueberries, sugar and gelling agent Photo: Stine Koopmann
I then did a gelling test for the jam. To do this, place a teaspoonful on a small plate, bowl, etc. Alternatively, a cool metal spoon will also work. If the jam becomes firm and has the desired slightly thick consistency, it can be bottled. It will then have a good consistency when it has cooled down. If the jam on the plate does not thicken, simply continue cooking the jam for another minute and then repeat the gel test. If the jam does not thicken after further testing, you can add citric acid to sweet fruits to help it set better. This can be either a few drops of lemon juice or citric acid in powder form.
Once this was done, I used a funnel to pour the jam into the disinfected jar and screwed the lid on. To cool, jam is traditionally turned upside down so that it can vacuum seal itself.
When checking the cooled jam, I noticed that it had become too firm and no longer flowed back down to the bottom of the jar when placed upright. I then checked my recipe again and realized that I had used too much gelling agent.
Now the jam has more of a jelly-like consistency. However, I don't necessarily find this bothersome. However, I find most jams too runny and prefer the firmer varieties.
It's very easy to preserve fruits and it's super quick. Especially if you want to use the fruit later for desserts or sweet dishes. If you want to eat it raw later, this method is less suitable. My conclusion is that you can do this more often, as long as you have the space to store the jars.
Jam is also very easy to make, at least in the quantities I made. It also depends on whether you use frozen berries/fruit or fresh ones for production. Frozen fruit takes longer to thaw, which prolongs the process. Nevertheless, overall, jam is very easy to make and I would do it again. You can be very flexible with how sweet you want the jam to be, but you should also make sure that you don't use too little.
Finished products Photo: Stine Koopmann
References:
Federal Ministry of Agriculture, Food and Home Affairs (Federal Ministry of Agriculture, Food, and Rural Affairs). (2025). Lebensmittelabfälle in Deutschland: Aktuelle Zahlen nach Sektoren (Food Waste in Germany: current figures by sectors . Federal Ministry of Agriculture, Food and Home Affairs (Federal Ministry of Agriculture, Food, and Rural Affairs). https://www.bmleh.de/DE/themen/ernaehrung/lebensmittelverschwende/studie-lebensmittelabfaelle-deutschland.html
Food and Agriculture Organization oft he United Nations. (2015). Food loss and waste facts [pdf-poster]. https://openknowledge.fao.org/items/18346ca4-1b2f-4ab5-95eb-d68e838b87ed
Hill, Susan. (2025, June 13 ). Getting Started with Food Preservation: Why It Matters . extension. https://www.aces.edu/blog/topics/food-safety/getting-started-with-food-preservation-why-it-matters/
Leda Meredith. (2022, March 25). Testing homemade jelly for the gel point. the spruce eats. https://www.thespruceeats.com/testing-homemade-jellies-for-gel-point-1327874
Ryslett, Kari. (2025). Juicing, pickling and canning-canned pears.
Siggi. (nd). Blaubeer-Marmelade (Blueberry jam). einfach backen (easy baking). https://www.einfachbacken.de/rezepte/blaubeer-marmelade-kochen-schnell-einfach?portions=2
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