Ice cream kills the heat!
Our chemistry lecturer gave us this ice cream project in October,
and yes, it was totally awesome, exciting and inspirational!
People asking about what am I studying actually,
from a pure culinary arts diploma, now studying chemistry and biology,
"who are you, what are you actually?" some people asked.
In short,
type CULINOLOGY in google.
It's something like Food science+Food Techonology+Culinary Arts = Culinology!
Anyway,
get back to the topic.
Ice-cream, yumm yummm.
And so, our task was making own exclusive ice-cream machine.
Taaaa-Daaa!
It's a chemistry project, yes, chemistry.
Understanding chemistry and apply it on food.
Taaaa-Daaa!
It's a chemistry project, yes, chemistry.
Understanding chemistry and apply it on food.
Ice cream was truly easy to make even without a machine or a home ice cream maker , but of course, convenience of these products is unarguable.
But if you have time, why not try making them by yourself which gives you more satisfaction?
And I'm telling you, the ice-cream made by simple mechanism is NOT inferior to the ice cream you buy outside. :)
# Rule 1 : Thermal Insulation
Having a good thermal insulation as the outer layer is important, in order to pertain the freezing cold temperature inside to freeze your ice cream mixture. Plastics is a good thermal insulator but not as good as wood or ceramic. If plastics is being used, the heat transfer will be taken place faster, and this cause the coolants to lose its coldness, as temperature increase.
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We decided to use ceramic flower pot, since I have a few at home. However, the main point of using it is because of its excellent thermal insulation property which helps to maintain and prolong the cool temperature of coolants inside the flower pot while freezing and churning the ice cream mixture.
We actually use ikea chair pad, a polypropene sheet to line the inner part of the ceramic pot to maximize the cooling and freezing process.
Temperature is crucial in making ice cream!
If the temperature is not cold enough,you might get whipped cream before it is cold enough to freeze the mixture for the ice cream (since you are going to churn your ice cream continuously).
#Rule 2 Fast, fast, fast cooling of ice-cream mixture!
As for the inner container where the ice cream mixture would be held, a normal milk powder tin is being used. Tin has high thermal conduction, which allows heat transfer to occur in higher rate, cooling and freezing the ice cream mixture more efficiently.
You know what, if the internal container is not good in thermal conducting, you might get whipped cream even before your ice-cream mixture can be frozen to make ice cream( since you still churn it continously)!
Therefore, having a good thermal insulator as outer container and good thermal conductor as the inner container serves the function right!.
#Rule 3 : Churn while freezing, Do it Fast, Scrap it more!
For the spindle, I bought stainless steel ruler as the scrapper by screwing them into a small wood roller. The bearing was also attached on the wood roller to ease and lubricate the spinning movement of the spindle.
When the ice-cream mixture is being frozen, it is crucial to crush the ice crystals into smaller and finer crystals to achieve a silky smooth texture. On the other hand, the spindle also helps to incorporate air into the ice cream mixture, giving the ice-cream a better volume. Scrapping of the ice-cream mixture in the tube aids in making better quality of ice cream, as the ice crystals formed are being crushed and mashed more frequently, and also, helps the formation of ice cream faster by distributing the heat out from the ice cream mixture.
(This means that, you don't need to worry having frozen ice cream on the side of the container, and the center part remains liquid.)
To spin the spindle, we thought of using a hand crank or a bridge, but the price of these attachments aren't practical for a small machine project. And therefore, we used this household hand driller to operate the spindle, it helps a lot, seriously. We hammered a nail into the center of the wood roller vertically until half way, wrapped it with whole lots of duct tape, for the grip of the hand driller.
#Rule 4 : Cold, Very cold, Freezing Cold!
Forget about liquid nitrogen and dry ice when you can get your superior quality of ice-cream with cheap materials. Use ice and salt, that's it! Ice itself has melting point/ freezing point of 0 Celsius, but when salt is being added, it lowers down the melting point, this means that now the temperature remains under 0C albeit some of the ice have melted into liquid form. Here, we used 500g of Salt to 1 kg of ice.
In fact, adding little a little bit of water helps to freeze the ice-cream mixture faster since it has larger specific heat capacity as compared to ice's heat specific capacity. In other words, it helps to absorb more heat from the ice-cream mixture.
I was worried about the machine, crossing fingers and praying really hard, wish that the ice cream will turn out magically. Curiosity always the best motivation.
First Attempt :
I used more than one hour to get to this stage. Too soft, too sandy, taste is good, but overall not a good one. :(
For the first attempt, I didn't have enough ice cubes, so I filled through half way, and that's no really efficient. Besides that, I stabilize the milk tin, sot that only the spindle turns instead of the whole milk tin.
From here, I realised that, it's better for the milk tin to spin together with the spindle, in fact, double spinning, double effect...
And it works!
Second Attempt:
Jason made a wood rack to hold the hand driller, brilliant! :)
Taaaa-Daaa, and this is what we get!
Oreo Vanilla Ice Cream
This ice cream is farrrrrrrr better than the first attempt, it is too good that can't be described.
Smooth and rich, everything is just so right. :D
We are happy kids after having a great success in making ice cream, and so we make can drinks sorbet. :)
It was truly exciting!
Why not you try? Here's some example:
Zip Lock Ice-Cream : http://spoonful.com/recipes/homemade-ice-cream-bag
Be creative, you can think of something more thrilling!
Watch this!
Shaking, kicking, throwing, any motion that cause collision, helps to 'beat' the ice-cream mixture too!
Be creative, you can think of something more thrilling!
Home made ice-cream made by "home made DIY ice cream machines". I can see the ice cream texture has resulted as real commercial standard...LOL never try these before. It's also providing fresh made quality. For me is like never known this kind of methods is so creative idea.
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