Preservation of fruit, berries and vegetables

Preserving fresh ingredients like red currants or onions is a great way to make them last months if not years. Especially in the winter when there is sparce availability of fresh produce, the effort and taste of summer will make you feel warm inside. That is why I made jam out of freshly picked red currants and pickled red onions.

Red currant bush / © Adobe Stock

Preparation

      Before you can start the process of cooking the onions or the jam, you need clean and sterilized jars and lids. An easy method is to clean them with a bit of dish soap and rinse them thoroughly. Afterwards you boil the lids in some water and put the jars in the oven at ~100 degrees for at least 10 minutes. Then you gather all your needed cooking utensils like pots, bowls, scale etc. as well as the ingredients.        

      Pickled red onions

Finished pickled red onions / © F. Brietzke

I started with the pickled red onion because of the mess I expect from the jam making. I decided to make two versions: one with chilli and one with lime and thyme. I cut one garlic, one chilli and two onions in rings. Afterwards I measured the vinegar and water. Because I was suspect of the sparse liquid from the other students that also made pickled onions, I looked up a recipe online (Vais, 2021). All of them recommended a 1:1 ratio. So, I decided on 150ml water to 150ml vinegar. I added that to a small pot and continued with 1,5 tbsp sugar and half a tablespoon salt. I cooked it until the salt and sugar dissolved. Following this, I added the garlic, onions and peppercorns and let it simmer for approximately 2-3 minutes. After that, I let it cool down, took my sterilised glasses out of the oven and added the chopped chilli to one and the thyme and lime zest & juice to the other. Finally, I distributed the onions and the liquid to the two glasses.

Veggies in preparation / © F. Brietzke

After they cooled down, I realized that it was still not enough liquid to cover everything sufficiently, but I am glad that I made more than the given recipe told us to (it says 150ml water and 50ml vinegar). I have not tasted them yet so I cannot assess the taste nor the texture.

Red currant jam

Finished jam / © F. Brietzke

Next up is my currant and currant-raspberry jam. The day before I made the jam, I picked around 900g of red currants at my roommates grandmother’s garden. In the evening, I removed all the leaves and large stems and picked out the imperfect ones and stored the remaining in the fridge.

Preparing, weighing, cooking red currants / © F. Brietzke

      At first, I weighed all the ingredients: sugar, the berries and pectin. I started with the pure red currant jam. I was uncertain if I should make whole jam or gelee – but decided on the whole jam for an easier and extensive result. 

     To begin with I cooked down the currants with a few ml of water, before adding my sugar and pectin. In the given recipe it says ~600g of sugar per kg of berries. I used 500g berries and added around 250g sugar. For the pectin I added around 10g, but realised later, that I could have used much more. 

      But as Maria Parloa said: “In no department of preserving does the housekeeper feel less sure of the result than in jelly making.”(Parloa, 1917, p. 24). 

      And I must agree, at least when you’re used to “jam sugar” (german: Gelierzucker, meaning a premix of sugar and pectin) like I am from Germany. 

      After I cooked and mashed everything for approximately 2-3 min I transferred the jam to my sterilized jars, put on the lid and put them upside down. Directly after that I repeated the process with the remaining currants and frozen raspberries. The total fruit came to ~700g. I added around 350g of sugar and much more pectin. The result was a much more jelly like consistency instead of a liquid consistency like the currant jam. 

red currant-raspberry jam upside down / © F. Brietzke

      Because I used a 1:2 ratio of fruit to sugar I wonder, how it would have tasted if I added less or more sugar or if a sugar alternative could be an option. According to the Journal of Food Processing and Preservation an accepted option could be “marmalade with a 50% reduction in sugar (8.23%), sweetened with stevia extract (2.05%), was equally accepted by the consumers when compared to the marmalade sweetened only with sucrose.” (Souza et al., 2022, p. 3). 

     A marmalade fully made of a sugar alternative such as Stevia or Xylitol however would not be an option for me personally.

      Conclusion

     After I cleaned up my workspace I was left with 2 full glasses of red currant jam, 2 and ¼ glasses of red currant-raspberry jam and two glasses of pickled red onions. I then enjoyed my red currant-raspberry jam on a slice of freshly baked banana bread at home.

Banana bread with selfmade jam & a great view / © F. Brietzke

In conclusion, I learned that jam making is different every time depending on the gathered fruit/ berries and the country that you’re making it in. Even though I have made jam and gelee quite a few times before. I have never pickled onions before but feel confident in doing it again with a different ratio of water & vinegar as well as different additives like lime or ginger for example.

      I am looking forward to trying the preserved goods at the end of the year and see how the taste and storage life is holding up. 

      Sources

      Parloa, M. (1917). Canned Fruit, Preserves, and Jellies: Household Methods of Preparation. Project Gutenberg.

            Souza, P. B. A., De Fátima Santos, M., De Deus Souza Carneiro, J., Pinto, V. R. A. & Carvalho, E. E. N. (2022). The effect of different sugar substitute sweeteners on sensory aspects of sweet fruit preserves: A systematic review. Journal Of Food Processing And Preservation, 46(3). https://doi.org/10.1111/jfpp.16291

           

          Vais, M. (2021, 01.12). Quick pickled red onions. https://elavegan.com/pickled-red-onions/