I was experimenting making ice-cream without using a blender or a freezer to see if this could be done easily with children. I did not find anything on the internet on making ice sticks. There are many YouTube videos on how to make ice-cream but nothing on ice sticks. So I decided to try to make ice sticks as well as ice-cream or rather frozen milk.
I put a small amount of UHT full cream milk and a small amount of orange juice in two food grade plastic bags. The amount of each was about the size of a cupped palm.
Then I loaded a plastic jar with ice from four ice cube trays and about 1 generous tbsp serving of sea salt. Apparently, rock salt works better but I only had sea salt.
I then placed the two packets into the jar of ice, closed it and the fun begins. Roll the bottles for 5-7 minutes. I think using a jar for the outside container is actually better than a bag because there is less skin contact and therefore less heat from hands will come into contact with the container holding the ice cubes (as opposed to when one uses a bag). You can shake the bottle, roll it, turn it upside down and after about 5 minutes, check to see if the milk and orange juice have solidified. Be careful that the bottle jar remains closed. If you want it more frozen, then shake the jar for longer. If the jar gets too cold to hold, wrap a tea towel around it.
When done, open the jar and unknot the bags and serve. For ease of opening, especially with children, you may use a ziplock bag for the juice or milk. Or if you knot the bags, make sure they are not so tightly knotted that you cannot unknot them easily.
The trick with this is the amount of ice and salt. Again, there are measurements on the internet on how much to put. One can be more generous with the sea salt. The temperature in the jar drops significantly to the point where the tea towel actually sticks to the jar – it is that cold! Salt basically lowers the melting point of ice which is why salt is often sprinkled onto iced roads in winter in cold countries. Hence the ice in the jar melts even as the temperature drops.
To make the servings more appetising, add whatever you want to it. Sugar, cream, flavouring and other ingredients can be added to the milk so that it better resembles ice-cream.