How carbon-heavy is my favourite cake?

One of the recipes I go to time and again is Nigella Lawson’s Madeira cake (turned in to a lemon and poppyseed cake with some additions), in How to be a Domestic Goddess. A domestic goddess I may be, but am I a domestic carbon sinner too? Firstly, set the oven to gas mark 3, or 170 degrees celsius.

Ingredients Directions Carbon factor (kg CO2e/kg) Carbon emissions (kg CO2e)
240g softened unsalted butter Cream 3 ingredients together in a large mixing bowl 9.5 2.28
200g caster sugar 0.6 0.12
Zest of 1 lemon (counted with lemon juice)
3 large eggs (60g each) Add each egg individually with a spoon of the flour 1.6 0.29
210g self-raising flour Fold the rest of the flour in to the mixture. 0.361 0.08
90g plain flour 0.361 0.03
Juice of 1.5 lemons Stir seeds and juice gently in to the mixture 0.6 0.14
2 tbs poppyseeds 2.9 0.04
23 x 13 x 7 cm tin, buttered and lined Put mixture in tin.
1.5 tablespoons caster sugar Scatter sugar over the top of the cake mixture before it goes in the oven. 0.6 0.02
Gas used to cook the cake for 1 hour 10 mins. (My oven used 0.917 m3 of gas)  (Recipe says 1 hour) 2.035kgCO2e/m3 1.87

Lemon and poppyseed cake

The cake’s carbon footprint is hugely influenced by the amount of butter and the time it takes in the oven. The cake also tastes far healthier than it is, so this may be a final nail in its coffin! 4.9 kg CO2e for one cake. I will be trialling other cakes to find an alternative… From this assessment, vegan or raw cake recipes should be far lighter on the planet. Any recommendations gratefully received.

(Please note, all carbon factors are based as far as possible on UK assessments, but there is great variety of figures between different assessments, depending on the assessment method used. I will be producing a list of carbon factors for food products to provide all the references.)

2 thoughts on “How carbon-heavy is my favourite cake?

  1. Interesting calculations! The butter could be replaced by a mild tasting oil like canola (GM-free of course) or peanut oil. In summer, cooking could be done in a solar oven. I have successfully baked bread loaves in mine. Alternatively using the same recipe but making muffins instead of cake would cut the cooking time by more than half 🙂

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