• Chocolate date meringue cake (Murdoch Books / Greg Elms)Source: Murdoch Books / Greg Elms
Colloidal suspensions, emulsions, globules, denaturing... every time you cook, you're an accidental boffin. Here's how clever you are. #ScienceWeek
14 Aug 2020 - 11:08 AM  UPDATED 14 Aug 2020 - 12:05 PM

There's nothing quite like a themed week/month/year to make us see things in a new light. National Science Week is a case in point. Scrolling through the available online courses, lectures, resources and tours, we were quickly lost down the rabbit hole that is the InquiBox At Home Science Scavenger Hunt. It's for kids, but that wasn't going to stop us.

We learned:

  • Inside each small kernel of corn is a drop of water and that's why it pops when it's hot.
  • Cutting an onion releases enzymes that make you cry (boo to you, syn-propanethial-S-oxide!)
  • Another enzyme, known as polyphenol oxidase, is responsible for triggering an apple's flesh to turn brown when it's exposed to oxygen.

How about that?

All this time in our kitchen lab coat has reminded us that science is happening every time we cook. Here are a few key reactions that will surely add further interest in cooking dinner night after night. 

Hollandaise chain reaction

A colloidal suspension is a mixture having particles suspended in a continuous phase with another component. Hollandaise sauce is what it looks like in the kitchen. Add some lemon dried myrtle-spiced banana prawns and you'll quickly be appreciating the finer points of science.

Blender Hollandaise

This recipe means you can have creamy, slightly tangy homemade hollandaise in less than 10 minutes. Chef Desiree Nielsen serves hers drizzled over over fried eggs and spiralizer fried potatoes.

Mayo emulsion

Mayonnaise is another excellently creamy example of a colloidal suspension. Egg acts as an emulsifier to bind the oil and lemon (or vinegar) together. Like a finicky marriage, if you don't get your oil/acid parts correct, the egg hasn't got a chance and mayo will separate. It helps a great deal if the ingredients aren't ice-cold from the fridge. As in all things, bringing ingredients to room temp is generally a good idea.

Whipped suspension

Vietnamese iced coffee pavlova

Whipping cream turns it into a foam - a suspension of gas bubbles stabilised by triglycerides either sticking together or attaching themselves to air pockets in the fat globules in the cream. The word 'globules' is enough to turn you off whipped cream forever, isn't it? Fear not, this iced coffee pav will soon bring you back to your senses.

Strawberry rhubarb clafoutis with coconut whipped cream

This simple and elegant dessert is a great way to showcase seasonal fruit. You can make one large clafoutis and slice to fit your number of diners, or make little individual clafoutis. 

Frozen strawberry tartlets with vanilla whipped cream and meringue

A new dish is always an exciting and rewarding moment for any cook, but there is a lot of trial and error to get it just right. After countless re-working, I think this recipe is the perfect iced tart. It’s a little bit demanding but worth the challenge – both in terms of appearance and flavour.

Easy tiramisu

Meaning "pick me up" in Italian, this version of the classic dessert tiramisu recipe by chef Vanessa Martin, is sure to do just that. 

Mother denatured

Chocolate date meringue cake

Speaking of pavlova, let's talk about meringue. The ability to turn egg whites into a soft, structured dessert is surely a magical thing. Yep, science is more than a little magical. When you whisk egg whites, bubbles form, creating a foam. The wires of the whisk beat the proteins, which unravel - a process known as denaturing. These proteins net together and keep the bubbles from popping. The added sugar in meringue helps more proteins gather on the surface of the air bubbles, stabilising them even further.

The tiniest bit of yolk in your egg whites will wreck the entire meringue.

Top tip: the tiniest bit of yolk in your egg whites will wreck the entire meringue. This is because the yolk contains fat molecules, which push the proteins away from the air bubbles, causing them to pop. Any hint of oil or butter on your whisk or bowl will have the same deflating effect, so for a puffy meringue, make sure everything is spotlessly clean.

A little salty over here

Salt-preserved citrus skins

We clever humans have been using salt as a food preservative since Ancient Roman times. Salt is able to preserve almost all foods for months or even years via a process of osmosis. Through osmosis water molecules in the food transfer to the salt, dehydrating the bacteria that would usually decompose the food. Not only that, but salt enhances the flavour of food, making salt-preserved foods very tasty indeed. Something you'll quickly find out when you drop a few of these salt-preserved citrus skins in your next tagine.

Rendered better

Ah, steak. Bacon! And, oh goodness, pork crackling. Rendering is very welcome indeed. It's basically the process of heating at a low temperature until all proteins solidify and any water evaporates. The result is a crispier layer left on meat and rendered lard to melt and use for cooking another day. Rendering breaks down the collagen in muscle fibres, which in turn makes your steak more tender and your pork sensational. See also 'caramelisation', below.

How to make the ultimate pork crackling
Making a gorgeous crackling has always been a bit of a mystery, but don’t worry! We’ve got some handy tips to get you to pork crackling heaven.

Good fermentations

Pink pickled eggs seem like the perfect place to start to explain fermentation. They're just so pretty that it's hard to believe they've basically been eaten away at by millions of microbes. To ferment food, you carefully balance the temperature and pH to encourage the growth of good microorganisms. These happily munch away on the parts of the food that usually spoils, releasing chemicals as a by-product to preserve and change its flavour and texture into something altogether delicious. Thank you microbes!

Pickled seaweed

Use pickled seaweed as you would any other pickle. It’s great with a sharp cheese, cured meats or to enrich a broth-based soup.

Cabbage kimchi (pogi kimchi)

Aside from barbecue, kimchi is probably the dish most synonymous with Korean cuisine. This fiery red, funky, fermented cabbage is on the table every meal – breakfast, lunch and dinner, 365 days a year. 

Yucatán pickles

You can find these pickles at pretty much every taqueria and taco stand in Yucatán, Mexico. They’re super easy to make and are a great addition to tacos, sandwiches, burgers, hot dogs as well as fresh seafood. 

Caramelisation station

Vanilla crème brûlée

It's why onions cooked with a little sugar taste so good. Why carrots and pumpkins are sweeter when baked. It's how cream and sugar turn into dulce de leche and why the top of crème brûlée cracks just so. It's caramelisation and it's a bonafide marvel. This non-enzymatic browning reaction occurs when water is removed from a sugar, followed by isomerization and polymerisation reactions that are as complicated as they sound. All we really need to know is that there is a chemical released during the process, producing that characteristic caramel flavour we all love so much.


Chocolate self-saucing pudding jars

A sloppy mess of batter, powder and water somehow magically transforms itself into the best winter dessert around. TBH, we're not entirely sure how self-saucing puddings work, but we are very grateful that they do. It will have something to do with creating layers that interact with other layers in specific ways but... yeah, we've got nothing.

If anyone out there is more than a kitchen boffin (ie, an actual science-y boffin), we'd love to learn the science behind these little pots of yum. If you could also unravel the mystery behind the impossible pie, that would be fab. We are all ears, and spoons.


Kitchen science
How to make caramelised onions while you sleep
Heaven is you, me, a slow cooker and a kilo of brown onions. Really, I promise.
The science of ceviche - is it cooked?
Is it possible to 'cook' without heat? And can scientists and chefs agree on the best way to make ceviche?
Science in the kitchen: the fresher the flour, the softer the cake
You may never feel disappointed at having baked a course textured cake again.

A fizzy-drink addict? Loved a sugar-laced iced tea in your past life? Let me introduce you to The ’Bucha. 

Mexican chocoflan

This rich, decadent cake is also known as pastel impossible (impossible cake) and for very good reason – the moist chocolate cake and creamy custard layers swap spots (completely!) during baking. The caramel topping traditionally used is cajeta (Mexico’s sugary goat’s milk caramel), but I have used dulce de leche (caramelised sweetened condensed milk) in this recipe, which is far easier to find outside of Mexico!

Rendered lard

You can use lard to cook eggs, meat and vegetables, especially potatoes. I made some sweet potato fries with this lard and they were really tasty, not greasy at all. If you have rendered leaf lard, you can use it instead of butter (or in combination with butter) in baked goods. Make sure to try it in a pie crust for a perfect, flaky crunch.

Preserved lemons

Zesty, citrus preserved lemons in jars create such a welcome bright light in any kitchen. They are great in North African, Mediterranean and Middle Eastern dishes, and work well wherever fresh lemons do — with fish, white meats such as chicken and rabbit. Once opened, keep a jar of your own preserved lemons in the fridge to give an instant zing to salads, or finely dice it into paellas, tagines, couscous and rice.