# Colligative property of ice cream HELP

1. Jan 4, 2006

### Mk

Colligative property of ice cream HELP!!

How is the colligative property in effect during the manufacture of ice cream, and in the ice cream??

2. Jan 4, 2006

### Staff: Mentor

http://www.chm.bris.ac.uk/webprojects2003/brown/thepropertiesoficecream.html

During the manufacture of ice cream one uses chilled brine (water with dissolved salt that lowers the freezing point) to get the temperature of ice cream down below the freezing point of water. Also, the freezing point of ice cream is reduced as mentioned in the quote and reference.

Colligative Property of Water Containing Rock Salt - http://www.waycross.edu/faculty/bmajdi/coligative properties of ice creaqm.htm

See also - http://pubs.acs.org/cen/whatstuff/stuff/8245icecream.html

- http://www.foodsci.uoguelph.ca/dairyedu/glossary.html

http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/meltpt.html
http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/collig.html#c1

3. Jan 5, 2006

### Mk

WOW Jeez man, I can see why you added the grinning smilie at the end. :surprised. Thank you.

4. Jan 5, 2006

### Ouabache

I can vouch for the colligative properties of the brine solution with ice cream. I've been using a White Mountain hand crank freezer for over 20 yrs and I've noticed (qualitatively) the higher the proportion of rock salt to crushed ice layered between the can and the wooden bucket, the smoother the texture of the ice cream.:tongue2: Presumeably, the cream is freezing faster and therefore yields smaller ice crystals.

Now if you really want to accelerate the freezing process, you might want to try what two Chem E's did out in Iowa. The use liquid nitrogen in their recipe and claim it freezes almost instantaneously, giving a uniquely smoother ice cream. They are or in the process of patenting their process.

Last edited: Jan 6, 2006
5. Jan 5, 2006

### Mk

I've wanted to make liquid nitrogen ice cream for two or three years. If you got one of those ice cream makers, and poured in liquid nitrogen where the ice+salt would be, would it work??

6. Jan 6, 2006

### Ouabache

Actually of the methods I've heard about, they pour the liquid nitrogen (-200 deg C) directly into the mixture that becomes ice cream. ref1, ref2, ref3, ref4, ref5

I've never tried pouring liquid nitogen in replacement of the ice/salt mixture (-17 deg C). I am guessing that the wooden tub would freeze and could shatter. If the turning mechanism still functions, then you probably could freeze the ice cream that way. Let me know if you try this experiment.

Another chilling agent that is sometimes used to replace the ice/salt mixture, is dry ice (liquid $CO_2$, -78.5 deg C).

Last edited: Jan 6, 2006
7. Jan 6, 2006

### Mk

Ooops I knew that. It was in popular science before too.

8. Jan 6, 2006

### TheStatutoryApe

So the liquid nitrogen should just evaporate off the ice cream as you mix it? I need to try this out.

9. Jan 6, 2006

### Ouabache

That's true.
(always take the necessary precaution's when working with liquid nitrogen and dry ice. You can get some serious frostbite:surprised ).

Last edited: Jan 6, 2006
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