Homemade Violet Crumble {a delicious edible science project}

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Turn your kitchen into a chemistry lab! Create an amazingly frothy chemical reaction, to make your own honeycomb or violet crumble. Yum!

Homemade Violet Crumble - deliciously edible science project for kids

Australia Day is coming up, and I’m teaming up with a bunch of Aussie bloggers to bring you some fun ideas and activites to do with the kids (see the bottom of this post for all the suggestions). And I thought, for our contribution, we could dabble in a bit of yummy edible science.

If you grew up in Australia in the ’70’s like I did, then you would surely know all about Violet Crumble bars – that delicious, crispy, golden honeycomb smothered in chocolatey goodness – and their claim that “it’s the way it shatters that matters”. (For the non-Aussies, Violet Crumble bars are similar to Crunchie bars – only better!)

Aussie violet crumble recipe - science in the kitchen

Well, I have good news folks. I’m giving you a really good excuse to make your own Violet Crumble at home, in the name of education. This is like an chemistry class in your kitchen, and any (or all) sugar content is instantly justified by making science fun. If you were making these for Australia Day, you could even call it patriotic. Don’t you think?

(Also, before we start, I have a small confession to make. For the first decade of my life, I *may* have mistakenly called them Violent Crumble bars – which somehow seemed to fit with the whole shatter theme… Surely I’m not the only one?)

Anyway, let’s cut to the chase….

How to make homemade Violet Crumble

(Our version is based on this honeycomb recipe. Pop over to have a look. I’m also just adding a link to this alternate honeycomb recipe out of respect – not because their recipe is similar to ours, but because the emotional commentary throughout the post is hilarious. Ha ha!)

Honeycomb ingredients

Our supplies are all Australian brands, purchased from local grocery stores. I’ve added a few (affiliate*) links below to similar products.

You’ll need:

You can find sodium bicarbonate in the baking section of your grocery store. Depending on where you live, it may be called bi-carb soda, baking soda, bicarbonate of soda, bicarb, bread soda or cooking soda. (Note: it is not the same thing as baking powder, which has cream of tartar as an added ingredient, and reacts differently.)

Golden syrup is an common pantry ingredient in Australian households, but it may be harder to find in some parts of the world. Itโ€™s made from sugar cane, so its not the same as corn syrup or maple syrup. You might find it with the pancake ingredients or in the baking ingredients aisle. Otherwise, check your speciality stores, and if all else fails, then itโ€™s worth buying some online โ€“ you can thank me later. ๐Ÿ™‚

You’ll also need some common kitchen supplies: measuring cup and spoons, large saucepan with high sides and a heavy base, wooden spoon for stirring, candy (or meat) thermometer, large tray, baking paper and butter or oil for greasing.

What to do

1. Grease and line a baking tray.
The larger your tray, the more your honeycomb will spread, and so the thinner your end pieces will be. We used a large cookie tray, greased with butter and lined with baking paper. (Lining with baking paper helps to easily lift the honeycomb from the tray when it is cool.) Next time I think I’ll use a slightly smaller tray, to make the pieces of honeycomb thicker.

2. Add sugar, honey, golden syrup and water to a large saucepan.
Kids can help with this part! (Measuring out ingredients is fantastic meaningful maths practise for preschoolers. ๐Ÿ™‚ )

Preschooler adding ingredients to make violet crumble

3. Stir over low heat until the sugar has dissolved.
Kids can help with a few initial stirs, but after that, adults will need to take over. (The mixture will turn into hot toffee, which can scald badly.)

turning sugar into toffee

4. Increase the heat and bring to the boil. Cook for about 10-15 minutes, until the mixture reaches the hard crack stage (150 oC / 300 oF).
There’s no need to keep stirring, but do keep a very close eye on the temperature, as there’s a very fine line between perfect toffee and burnt. We used a digital meat thermometer, but if you have a fancy candy thermometer that can let you know when hard crack stage is approaching, that would be even better! If you have neither, you can also manually check if the toffee mixture hardens and cracks when you drop it in water – click here to read how.

Making honeycomb for violet crumble

5. When it reaches 150 oC, take the saucepan off the heat immediately.
Let sit for a few seconds. Now is a good time to call over the kids, so they can watch what happens next.

6. Add bicarbonate of soda, and quickly stir until combined. Watch the mixture bubble, froth, foam and rise!
This is classic kitchen science! And now you know why you needed such a large saucepan. ๐Ÿ™‚

Making honeycomb - chemistry in action

7. Pour the honeycomb mixture into the lined baking tray, and set aside to cool.
The honeycomb cools quickly once out of the pan and won’t scald any more, but it’s best left to set without little fingers prodding it, if you want good honeycomb results at the end.

pouring fresh honeycomb

8. Break up the honeycomb into little pieces. Melt the chocolate, and dip/drizzle over the honeycomb. Let set.
I transferred our honeycomb onto a large chopping board and broke it up with a knife. For a classic violet crumble style, completely cover the pieces of honeycomb in chocolate. Alternatively, for a modern twist, dip just one side in the chocolate and let set. Then drizzle chocolate onto the other side and let set again.

Cracking honeycomb

Drizzling chocolate over honeycomb to make violet crumble

9. Enjoy!
The dark chocolate takes the edge off the honeycomb sweetness. Just forewarning that it’s really easy to overindulge, so apologies for the sugar rush! IF there’s any left over, you can store it in an airtight container in the fridge. The ones completely covered in chocolate will store better, due to the hygroscopic nature of the honeycomb (which is why Violet Crumble bars were made this way in the first place). But, having said that, our partly covered ones are still tasting great, and we made ours several days ago now…

Homemade violet crumble recipe that kids can help make

Homemade Violet Crumbe - a delicious science project for kids

Honeycomb Science

Baking soda, or to use its chemical name, sodium bicarbonate (NAHCO3), is an alkaline or a base. Alkalines react with acids (you may have heard of this as an ‘acid base reaction’.) Citrus juice, buttermilk, molasses and vinegar are all acidic. So is the honey and golden syrup that we use in our recipe. When we add sodium bicarbonate to our sugar / honey / golden syrup toffee mixture, an acid base chemical reaction occurs, which creates carbon dioxide (CO2). Carbon dioxide is a gas, and causes the mixture to bubble, foam, froth up and appear to grow in size, turning our hot toffee into honeycomb.

honeycomb science

Please note…

The ingredients used here are all generally taste-safe (when cold), except for the sodium bicarbonate in its concentrated form. (It’s OK once it’s mixed with the other ingredients).

As always, be very careful with kids around hot stove tops, gas flames and when handling boiling hot ingredients. Hot toffee can cause especially nasty burns.

All kids’ activities on this blog require attentive adult supervision. Parents and carers will need to judge whether a particular activity is appropriate their childโ€™s age and skill level. Click here for more information.

For more fun edible Aussie science, you could try your hand at another of our edible fizzy Aussie science recipes – making Anzac Biscuits (yum!).

And check out these fun Aussie projects (below) from some of my Australian blogger friends!

Australia Day for Kids blog hop

The Australia Day Blog Hop 2016

Monday January 4th
Printable koala mask at The Craft Train

Tuesday January 5th
Koala in a Creek at Laughing Kids Learn

Wednesday January 6th
Australia themed printable at Montessori Nature

Thursday January 7th
Boab Tree Mosaic Art at A Moment In Our World

Friday January 8th
Homemade Violet Crumble recipe at Go Science Kids (that’s us!)

Monday January 11th
Aussie Book List at Honey Bee Books

Tuesday January 12th
Mini kids pavlovasat Kidgredients

Wednesday January 13th
Bottlebrush (flower) art at Danya Banya

Thursday January 14th
Lamington Drops – quick Aussie cookies kids can make at Coloured Buttons

Monday January 18th
Chocolate Lamington Scrolls at Sweet Little Pretties

You might also like to visit the Australia Day Blog Hop from 2014 for lots more fun Aussie ideas!

* This post contains affiliate link(s). An affiliate link means I may earn advertising / referral fees if you make a purchase through my link, without any extra cost to you. It helps to keep this little project afloat. Thank you for your support.

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  1. Kate - The Craft Train

    Oh yum! that looks amazing and so much fun for the kids to make

  2. Anastasia

    This is brilliant! Delicious treat and science what a great combination! Thanks for sharing!

  3. Kate

    Oh I haven’t made this is AGES! You’ve totally inspired me to try it again. Great post thanks Danya.

  4. trixi symonds

    Wow I love your recipe…and yes Violent Crumble does ring a bell ๐Ÿ™‚

  5. linda young

    I like how it gets crunchy! And its yummy, we are cooling it off right now,thanks for showing us how! Bye! I am 7 years old


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