Monday, 6 August 2012

Sydney Winters Day & the Science of Sugar

It was a perfect Sydney winters day on Saturday – sun shining, blue sky and a hint of a chill in the air – so I decided it was a perfect day for a trip to the Pyrmont Growers market. I love going there, but I don’t necessarily buy that much. I just love looking at all that beautiful fresh produce. I guess it’s the same reason I love going into other countries grocery stores when I’m travelling.
Fast Ed Halmagyi was there doing a cooking demonstration (sorry about the bad picture). The demonstration was good and he was funny, as to be expected. While he was cooking he talked a bit about some of the chemistry behind cooking. So for example, he talked about why things actually caramelise, and what needs to be there for them to caramelise. 
Listening to him talk got me thinking about why I have developed a passion for food and why I love cooking so much. When I was a kid, I was like my dad and a bit of a science nerd. I had the chemistry set, and dad and I would often do experiments on the weekend. And a lot of what cooking is, is a chemical reaction. There’s a science behind it. A logic, a pattern. Reactions. Testing. Learning. Experimenting. Developing. Although I loved it as a kid, I was never that awesome at science (hence I’m in advertising and not working as a scientist) but maybe that time spent playing around with my chemistry set was what helped me down the path to food. Maybe I have my dad (and yes dad, my gene’s) to thank for it. 
The other thing I realised, is that I have so much more to learn about the theory behind cooking. I can sit down and open a recipe book and cook something delicious, but there’s much more to putting together a meal than just opening up a recipe book and cooking. So I’ve decided that I’m going to try and learn one new thing about cooking a week. A theory or a technique. Something that will help me grow as a cook.

I’ve never ever successfully made caramel. I have worked with sugar to make nougat and cloud frosting, but caramel still alludes me. So I thought I’d start off learning a bit more about sugar. I know different heating temperatures have different results (soft candy, firm candy, hard candy etc), but that’s about it. 

So after a bit of investigation, I’ve found out that when you heat sugar, you break the simple sucrose (normal sugar) molecule up into glucose and fructose. As you continue to heat it, the molecules re-combine into new, more complex molecules. But this all happens in stages. At first just a few molecules break up. Then, the higher the temperature the sugar reaches, the more molecules break up. Next, just a few molecules will re-combine, but again, as the temperature goes up further, more molecules re-combine. So the reason that different temperatures give you different types of candy is because different amounts of molecules have broken up and then re-combined. 

Here are a few of the most common candy stages. If you don’t have a candy thermometer, you can also test it by dropping the melted sugar into cold water and you get different results. I’ve added the test as well as the temperature for each stage.

Soft-ball Stage: 112-116ºC, when a small amount of sugar syrup is dropped into very cold water, it forms a ball that does not hold its shape when pressed with your fingers. 
Firm-ball Stage: 118-120ºC, when a small amount of sugar syrup is dropped into very cold water, it forms a ball that holds its shape, but it still sticky, when pressed with your fingers. 
Hard-ball Stage: 121-130ºC, when a small amount of sugar syrup is dropped into very cold water, it forms a ball that holds its shape but is pliable.
Soft-crack Stage: 132-143ºC, when a small amount of sugar syrup is dropped into very cold water, it can be stretched between your fingers and separates into hard but not brittle threads. 
Hard-crack Stage: 149 - 154ºC, when a small amount of sugar syrup is dropped into very cold water, it will solidify but will separates into hard brittle threads. 
Light Caramel Stage: 160-170ºC, poured onto a white plate the syrup will be honey-golden in color.
Dark Caramel Stage: 177ºC, poured onto a white plate the syrup will be deep reddish amber in color.

So today, I've learnt something new about cooking...Despite the sciencyness of it, I hope you learnt something new too. 


  1. Liss, love the pic of you and Arielle, so gorgeous!

    If you're going to make caramel, I'd suggest using white granulated sugar rather than caster. It seems to behave itself more than caster, I think it's more stable, so it's less likely to crystallise (when it goes all white and crunchy). Also, sometimes people add a little glucose to their sugar and water to help avoid this.

    Also, dissolve the sugar first then boil rapidly and don't stir once sugar has dissolved.

    What will you make with it? Creme caramel? Salted caramel and chocolate tart? Mmmm...

    1. Thanks Tina! Had to pull through the archives to find that one.

      Thanks for the tips on the sugar. I might share them next time I do a tips post if that's cool?

      I actually didn't have anything in mind to cook with sugar, but now that you mention it, I do need to cook a desert for dinner Saturday night, and I think something with salted caramel, chocolate and peanut's is in order. Know any good recipes? Need to try out my new found knowledge! xx

  2. Gosh Liss, doesnt matter how many times I try, taking carefully to follow each and every step of a recipe, including buying and using a candy thermometer, I CANT MAKE TOFFEE. I want to be a successful tuck shop/fete mum - aahhh the memories of sucking on a soft cracked toffee with 100s and 1000s on top! Ps. Love that photo - what a blondie! ADORABLE!

    1. Me neither!! Maybe we need to get together with Jen, and use Tina's tips and try last attempt at making toffee!! xx

  3. In a homemade tent under the cherry tree. Great childhood.