Square tin for Christmas cake?

[fatsatsuma]

I'm using a recipe for a 23cm round tin, but would like to use my 21cm square tin. Does anyone how to work out the comparable volumes of the two tins?

They are very similar in size/volume. The surface area of a 9" (23cm) Round pan is 56.6 square inches, which is the equivalent of 8" x 7" (20cm x 18cm). 8" x 8" is 64 square inches if you can remember your 8 times table. If you really wanted to match identically, you need to increase your recipe by 1/8th, but in reality, use the existing recipe; the cake will just be a little shallower.

Thanks, that makes sense. I wonder if I would need to alter the cooking time though, if the cake was shallower. I always seem to undercook my Christmas cake, and was planning to stick rigidly to the recipe this time.

if you can wait till I get home, the Leith's baking bible gives equivalents for square and round tins and I can look it up for you, with cooking times...will be there in about 3 hours

Thanks rhetorician, that would be great. Hope the hours go quickly.

fatsatsuma - the Baking Bible suggests that a 20cm square tin is equivalent to a 23cm round tin (in imperial the square measurement is one inch smaller, so 9 inch round = 8 inch square, and the other metric sizes are 2cm different). This is for a rich fruit cake using the creaming method, and suggested cooking time is 3 1/4 hours at 150c/300F/gas mark 2. So I'd say you'd be alright, but check the cake about half an hour before the end - you can put a circle of damp greaseproof on the top to stop it browning too much.

HTH - and that you get a yummy cake this year!

Thank you - that is really helpful - will let you know how the square cake turns out!