Scaling Mary Berry

November 17, 2020 4:26 PM

My mother would like to make two small Christmas cakes this year rather than one of the usual size. She uses the Mary Berry recipe. She has a 5in tin and a 6in tin at her disposal. Obviously she can divide the batter proportionally. But how should she adjust the timings? And should she do one cake at a time or do two different sized cakes simultaneously?
posted by hoyland to Food & Drink (7 answers total)

I was just reading Stella Park’s article on scaling up/down cakes. See her response on adjusting the temp and timing in Q 7 and 8.
posted by inevitability at 5:29 PM on November 17, 2020

From my notes baking a two-tiered fruitcake for a wedding: "A full, 9 or 10-inch cake will require 5 1/2 hours to bake; smaller 5 or 6-inch cakes 4 1/2 hours; mini-cakes 2 3/4 hours."

I bake at 325 for half an hour, reduce to 275 for another two hours, then remove the parchment, give the tins a quarter or half turn, and finish baking.

I bake multiple cakes at once.
posted by JawnBigboote at 5:30 PM on November 17, 2020

For Mary's recipe, I'd start checking at 3 hours just to be safe, and allow at least another hour.
posted by JawnBigboote at 5:32 PM on November 17, 2020

First of all, the length of time a cake should be cooked is mostly based on the thickness of the cake, not its area. That is, most of the heat cooking a cake comes through the top and and bottom. Although, a smaller cake will take less time as the sides of the cake are closer to the center. So, if you fill both tins to the same depth, I'd say they'd need to bake a little less than the full-size 9" cake, and the 6" cake should need a little more time than the 5".

The original recipe calls for a 9" tin. Normally, πr2 is used to calculate area, but to make it easier since they cancel out in ratios, I'll drop π and use the diameter instead of the radius. The area of a 9" tin is 9^2 = 81. The 5" tin has an area of 5^2=25. The 6" tin has an area of 6^2 = 36. The 5" and 6" tins' areas add up to 61. And 61/81 =~ .75.

The recipe should be able to cut in 3/4 and the tins should be filled to the same depth.

Since the original recipe is s a low temperature bake with a long cook time of 4-4.5 hours and you know the cake is done when
"the cake feels firm to the touch and is a rich golden brown", I'd bake both cakes together, start checking doneness at 3 hours, and expect the 5" one to finish before the 6" one.
posted by ShooBoo at 5:37 PM on November 17, 2020 [2 favorites]

Wouldn't it just be simpler to send your mother either another 5" or another 6" tin, or even get her two identical ones the same size and not have to worry about it all?
posted by mareli at 5:51 PM on November 17, 2020

Response by poster: Wouldn't it just be simpler to send your mother either another 5" or another 6" tin, or even get her two identical ones the same size and not have to worry about it all?

To clarify, she's not planning on/wedded to doing a 5in cake and a 6in cake, those happen to be the smaller cake tins at her disposal. She's perfectly happy to do use the same tin twice.
posted by hoyland at 5:38 AM on November 18, 2020

Response by poster: It turns out that the BBC has a calculator albeit one that works only in the UK.
posted by hoyland at 5:00 AM on November 21, 2020