Math is hard: fruitcake edition

November 16, 2019 9:36 AM

What is the target internal temperature for a cooked (but not overcooked) fruitcake? And lord almighty can you help me figure out some volume conversions for a 25cm pan?

Festive greetings! I am getting a late start on my fruitcake this year, but have decided to revisit a recipe I tried a few years ago (this Australian widower's cake). Here's the thing....the last time I made it I did so with a friend, so we doubled the batch (KILOS of dried fruit! no bowls big enough!). She had a nice deep square pan, and I think I used two loaf pans? But I don't remember, honestly. There was a lot of brandy in play. I do recall it all took much longer to cook. It was delicious, at least.

So this year I am just making one batch but I do not have the 25-28cm square pan the recipe calls for (nor can I find one deep enough -- you can see from the photo how tall the cake is). But I'm not sure if two standard 9x5" loaf pans are enough. Looking at this list of cake pan volumes is not much help because the square pans listed are all shallow and I know the pan needs to be at least a few inches deep.

Question 1: can anyone figure out the volume of the pan the recipe calls for? If I know the original volume, I can figure out which other pans to use. Let's say, for argument's sake, 28cm square and at least 10cm deep. My brain stopped short at converting centimetres into liquid volume, to say nothing of my extremely Canadian habit of working in both metric and imperial simultaneously.

Question 2: anyone know offhand the target internal temperature for a fruitcake? That might help me avoid the pitfalls of over/underbaking in different pans.

THANK YOU! I'll send you all virtual fruitcake. Hell, I might even send you actual fruitcake!

posted by Mrs. Rattery to Food & Drink (10 answers total)

Response by poster: Oops! Forgot the pan size link.
posted by Mrs. Rattery at 9:38 AM on November 16, 2019

Best answer: The original link is behind a paywall, but I think this is the same recipe.

If we assume 5cm depth on the pan that is called for, then it's 3.5 liters. You could probably get away with a 33 x 23 cm pan (13x9 inches) since it isn't going to rise that much. Or two 23 cm (8 inch) round pans. Or two medium sized loaf pans. Or a 23 cm square pan and put some of it in a loaf pan or muffin tins.

Per this page, internal temperature for a dense type cake would be 200 - 205 F or 93 - 96 C. You definitely want to pull it before it hits 100 C.

Let me know how it turns out, I've never made a fruitcake and that one looks like a whopper!
posted by cabingirl at 9:56 AM on November 16, 2019 [1 favorite]

I can't get to the Australian newspaper link. But having made American fruitcake, I'd say that fruitcake is typically heavy and fruit laden and doesn't rise much in the pan. Thus, when you fill the loaf pans you have, you'll see if you need more pans. Two loaf pans will cook more quickly than one big square pan, of course, but that doesn't answer how long. As to doneness, instead of internal temperature the usual cake test works: put a skewer in the center and see if it comes out clean. Because fruit cakes are heavy and boozeful, the color of the top is not much help.

Good luck.
posted by tmdonahue at 9:59 AM on November 16, 2019

Oh, I missed the 10cm bit. I don't think most pans are that deep, I think you'd have to use a tube pan or a bundt pan. If it really was 10cm deep then you have to double the numbers, but I doubt you made 7 liters of fruitcake batter. I mean, that wouldn't fit in my mixer bowl I don't think.
posted by cabingirl at 9:59 AM on November 16, 2019

Response by poster: Weird -- for some reason I don't get a paywall! cabingirl's link is the right one. However, to head off a few things....

- the cake in the picture looks to be at least 5" in height. It's not a rise issue, it's a containment issue.
- the reason I'd like to have a better idea of volume is I am wondering if I could try my 9" springform pan, which is probably deep enough, but perhaps still a little small?
posted by Mrs. Rattery at 10:04 AM on November 16, 2019

Each of your loaf pans will hold just under 6 cups of batter (or just under 1.5 liters)

9x5 loaf pans (assumed to be 2.5 inches deep, filled to 2 inches to leave a little space for expansion) = (9x5x2)x(2.54x2.54x2.54)/250=5.8 cups

That seemed a bit high, but I just tested mine and the 6 cups of liquid fit with half an inch to spare. So your two loaf pans will hold a total of just under 12 cups (3 liters) of batter.
posted by Sauter Vaguely at 10:05 AM on November 16, 2019

Best answer: After reading the quantities of the ingredients in the recipe that cabingirl linked, I expect that you will have at least 4 liters of batter. And based on a 28 cm square tin that is 10 cm deep, you should expect almost 7.9 liters of batter.

Your springform pan could work if it is at least 20 cm tall:

Each centimeter of a 9" round pan will hold 0.4 liters of liquid: (4.5x2.54)^2 x(3.14) = 410 cm^3 = 410 mL = 0.41 L= 1.64 cups

So 0.41 L x 19.3 = 7.9 L

Edited to correct that the radius of a 9" pan is only 4.5". Stupid circles.
posted by Sauter Vaguely at 10:22 AM on November 16, 2019 [1 favorite]

My brain stopped short at converting centimetres into liquid volume

Does it help to know that a cubic centimetre is the same thing (by definition) as a millilitre, so a thousand cubic centimetres is a litre, which is four standard metric cups?
posted by flabdablet at 10:23 AM on November 16, 2019 [4 favorites]

My mom used to make a lot of fruitcakes, and I've made a few too. Your best approach to testing done-ness is described by tmdonahue: put a skewer in the center and see if it comes out clean; when it comes out clean the cake is right.

(You've already marked best answers, but you missed tmdonahue's!)
posted by anadem at 7:57 PM on November 16, 2019

As to doneness, instead of internal temperature the usual cake test works: put a skewer in the center and see if it comes out clean. Because fruit cakes are heavy and boozeful, the color of the top is not much help.


Agree with this suggestion, and also you might want to loosely cover the top of your cake with brown paper (with a whole cut out for steam) so that the top doesn't burn before it's cooked. Particularly an issue with small deep cakes, I think.
posted by plonkee at 4:46 AM on November 17, 2019