Tuesday, 6 August 2019

SUMMER SCIENCE SNIPPETS 3 - ICE CREAM

ICE CREAM

Where we live there is an ice cream man who comes around with his van and sells the most amazing cones covered in popping candy, nuts, sprinkles, sauce and if you are lucky a flake.


But what about trying to make it at home?
Everyone loves ice cream and home made can be simple or complex - it all depends on what you want and how much effort you put in.

There are custard based ice creams that have you cooking before you freeze
   
and there are simple mix together and freeze recipes. There are slushies and granitas and so many recipes on the web it is hard to decide.

I invested in an ice cream maker a few years ago - you freeze the bowl overnight and then add your ingredients as the paddle churns.
We have had some amazing successes and plenty of dismal failures - often because we want to use it on a hot day so it never really freezes.
The machine works by churning using paddles - the cold sides of the bowl freeze the mix and the paddles scrape it off . The real trick is to freeze but not to make large ice crystals - little crystals make a smooth ice cream.
Adding a flavour is important because when frozen things taste very different to when warm - so you have to get a good balance between strong enough but not overpowering


Now I have discovered frozen yoghurt  - just regular yoghurt churned until soft frozen and eaten straight away - it is delicious.

Surprisingly I still love ice cream even though I have spent many summers when I was at Catalyst making liquid nitrogen ice cream

this is me many years ago at Catalyst Science Discovery Centre Widnes
 I did a spot of teaching in Tennessee and a favourite of teachers there is to make "baggie" ice cream using a plastic bag, ice cubes and salt.
Amazingly it does actually work!



      

Here is a link to a website with more information
http://www.instructables.com/id/How-to-Make-Homemade-Ice-Cream-in-a-Bag/

One tip from someone who has had ice cream all  over the place and mixed in with the salt....use a double bag! All that manipulation of a very cold plastic bag can cause it to split.
Don't forget to keep everything clean and follow good food hygiene rules - enjoy!

The actual science of ice cream is quite complex because you would think that mixing cream, milk and sugar together would be easy but that doesn't make good ice cream. Think about the smooth texture, whether it is full of air or very solid, how fast does it melt and of course what does it feel like in the mouth.
Here is a poster from those amazing folk at Compound Interest. Follow the link to their page to find lots more about our favourite treat.

https://www.compoundchem.com/2015/07/14/ice-cream/








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