The Norfolk Volcano Team has a problem – we’re slightly obsessed with cakes. In fact we are so obsessed that we wanted a volcano cake competition to be part of the Norfolk Firework Volcano legacy (and we wanted to eat cake). Baking is a great way of demonstrating scientific principles and getting kids excited about science, we think that the sugar might help! We’re getting Tim Kinnaird, from Norwich’s very own Macarons & More to judge the competition, and if you want to enter the competition, all you have to do is register your entry by emailing your name, age and the name of your edible creation to email@example.com before the Festival and then show up on the day by 12.15. Registration closes on Friday 20th September, so to get you thinking about “volcano cakes”, here are some ideas for some truly volcanic baking…
1) Bake your cake… with lava
Now, in no way do we at Norfolk Firework Volcano endorse risky behavior around volcanoes – if it’s not necessary, don’t do it! Nonetheless, people have used the heat from cooling lava to cook food. Cremated chicken isn’t really our thing, but people have cooked more tasty looking things using the heat from a dormant volcano.
This suggests that we could bake a volcano cake using an actual volcano, but to be honest, it probably wouldn’t taste any better or look any prettier than if it were cooked in a conventional oven! So back to things we can actually do from the comfort of our kitchens.
2) Make a volcano cake a.k.a chocolate fondant a.k.a yum!
If you need further justification after that picture, you need to see a doctor. In the UK these are called chocolate fondants, but in the USA they actually have the right idea and call them volcano cakes. As far as we are concerned, they are basically small domes of lava that show the transition from ductile to brittle behavior that lava shows when it solidifies. If you put lava under stress, it will simply flow. On the other hand, if you apply enough force to a solid, cold rock it will fracture. Make this cake, get a spoon and you’ll see!
You can find a supposedly perfect recipe for a chocolate fondant here. We think a bit of raspberry sauce might be useful for the purposes of “realism”.
3) Make some transitional fudge
Can you spot the two different types of lava in the above picture? On the left hand side (the smooth looking rock) we have pahoehoe and on the right (the more angular looking rock) we have a’a. They look different because they were formed from different types of lava. More fluid lavas tend to form smooth bodies of rock, whereas thicker (more viscous) lava flows form blocky, angular lumps of rock. Well, we can recreate these different textures… using fudge! The way minerals grow in lava, as it cools, is similar to the way in which sugar crystallizes. When fudge cools quickly with little stirring, its surface looks smooth, but inside it is gritty because the sugar crystals have been allowed to grow (pahoehoe). When the fudge is stirred, this causes the sugar crystals to grind against each other, creating smaller crystals, but with a rough surface (a’a). There has been an excellent paper written about it, and further details and pictures can be found in this New York times article.
4) Make your volcano cake erupt
There are a number of ways to do this, some involve baking powder and vinegar (not very tasty), others involve coke and mentos (a big mess). The video below uses gelatine and dry ice, which although not easy to find, gives a great result!
5) Make lava lollies
This is a great way of decorating a cake to create a “I just froze midway through an eruption” look. You basically boil sugar with red food colouring and then splatter explosion shapes onto a cool surface. As can be seen from the picture below, it looks really impressive! More details on how to make lava lollies can be found here.
6) Go crazy with icing
Healthy eating is great, but to recreate lava flows on a cake we need sugar, and lots of it. Make some icing with a bit of red or orange food colouring in it, and hey presto, you have lava! And if you’re very smart, you’ll combine it with one of the above ideas to make something truly spectacular – just like the picture below, and in this recipe.