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/

SUMMER SCIENCE SNIPPETS 4

HOME MADE ICE CREAM
without a freezer using science!

As I am writing this we are experiencing the hottest weather so far this year. So what better way to cool down than with some ice cream

Everyone loves a cool ice cream in summer - the sound of the ice cream van is evocative of long summer days.

Making home made ice cream can be as easy or as complex as you want it to be.
There are many custard based recipes where you have to do proper cooking before you even get to freeze your mix.

There are super scientists all over the place making it with liquid nitrogen ( huge fun but don't try it at home!)

this is me many years ago at Catalyst Science Discovery Centre Widnes

There are home ice cream machines - some that do the whole thing can be quite pricey - others where you freeze the bowl overnight and the machine basically churns the mix are cheaper.

However there is another  method which uses a little bit of science knowledge to drop the temperature and freeze the mix.

This is a favourite of American teachers! I made this when I was teaching in Tennessee and it really does work.

There are lots of posts on the internet with recipes and instructions so here are a few links. Find one you like and have a go.
http://www.sciencemuseum.org.uk/~/media//Educators/Educators_downloads/icecream_in_bag.ashx

http://www.ljmu.chemistryforall.co.uk/making-ice-cream/

http://www.instructables.com/id/How-to-Make-Homemade-Ice-Cream-in-a-Bag/

One tip from someone who has had icecream 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.

If you are going to eat the ice cream - and why  not we ask -  you need to remember food hygiene rules and make sure everything you use is clean and hands are washed.

Have fun!!