Is my freezer malfunctioning?

November 23, 2008 5:28 PM

What does it mean if my freezer can free meat solid but ice cream remains soft?

I have a 15 cubic foot chest freezer. If you put a steak or a turkey in it, the meat freezes rock hard. If you put ice cream in it, the ice cream remains relatively soft. It won't melt and it is still definitely ice cream, but it's soft enough to scoop without bending a spoon doing it.

I'm confused by the disparity, it would seem that if it's cold enough to freeze a 20 pound turkey it's cold enough to turn ice cream rock hard. Is it just that ice cream is fatty and doesn't freeze as solid as meat? Do I need to service my unit?

posted by JFitzpatrick to Food & Drink (15 answers total)

put a thermometer in the freezer, if the temp is where it should be, why get it serviced... it is then, clearly, a matter of the makeup of the material being frozen...
posted by HuronBob at 5:32 PM on November 23, 2008

Are you putting the meat and the ice cream in the same location? This sounds like a job for Science.
posted by spikeleemajortomdickandharryconnickjrmints at 5:33 PM on November 23, 2008

Response by poster: The meat and ice cream are in the same location, it's a chest freezer so there really isn't the same kind of temp fluctuation you would have in a regular stand up fridge style freezer.
posted by JFitzpatrick at 5:36 PM on November 23, 2008

I think it might have something to do with the ice creme. If it has a lot of milk fat in it, it might not freeze as solid as it would if it had alot of water fillers.

IANAICE (I am not an ice creme expert)
posted by meeshell at 5:39 PM on November 23, 2008

I think meeshell is right. It's not the freezer, it's the ice cream. The dairy brands have a lot of air whipped into them and they never get really hard like a Ben and Jerry's would.
posted by bricoleur at 5:48 PM on November 23, 2008

HA! I almost asked this last week, I've always had the same exact problem. I'm starting to think it's about the milkfat.....
posted by tristeza at 6:01 PM on November 23, 2008

it seems like everything's in order:

Look, the sugar in frozen desserts is more than just a sweetener. See, once dissolved in the liquid, the sugar molecules actually get in the way of ice crystals forming. Now as more water does freeze, the remaining liquid becomes more and more concentrated with sugar which continually lowers the freezing point. That means that an ice or sorbet is little more than tiny ice crystals suspended in a supersaturated sugar solution that's basically never really going to freeze, not all the way.

-Good Eats Episode EA1A06, transcript found here from these fine people.
posted by heeeraldo at 6:05 PM on November 23, 2008 [1 favorite]

The difference has to do with the way ice crystals form in the material. A better crystal lattice makes for harder, more brittle ice. A more disorganized arrangement makes a solid that is softer and more malleable.

Think the difference between glass and silly putty. (although that's not the bestest example, it is illustrative.)

I wouldn't recommend service based on your description. This is perfectly normal.
posted by Pogo_Fuzzybutt at 6:05 PM on November 23, 2008

Ice cream as it's usually sold isn't supposed to be rock hard (that's why people use ice cream makers rather than just blending the ingredients and sticking them in the freezer - the ice cream maker process ensures there aren't big ice crystals and it's not a solid block of ice.) You might be able to get it to be almost rock hard if you left it out on the counter to melt completely and then re-froze it. (I've done that by accident before, or had it happen after power outages.)
posted by needs more cowbell at 6:12 PM on November 23, 2008

I work in an ice cream store, so I can tell you it's the ice cream and not your freezer. It depends on the kind of ice cream...all of our ice cream is kept in the same freezer, and some of them freeze up hard and others stay soft.
posted by god particle at 6:20 PM on November 23, 2008

From Googling "how does ice cream stay soft?":

... In addition, the sugars, including the lactose from the milk components, contribute to a depressed freezing point so that the ice cream has some unfrozen water associated with it at very low temperatures typical of their serving temperatures, -15o to -18oC. Without this unfrozen water, the ice cream would be too hard to scoop.

Freezing point depression of a solution is a colligative property associated with the number of dissolved molecules. The lower the molecular weight, the greater the ability of a molecule to depress the freezing point. Thus monosaccharides such as fructose or glucose produce a much softer ice cream than disaccharides such as sucrose. This limits the amount and type of sugar which one can successfully incorporate into the formulation...
posted by greenland at 6:52 PM on November 23, 2008

Response by poster: Thanks guys! Very informative stuff.
posted by JFitzpatrick at 9:43 PM on November 23, 2008

In my experience, cheaper ice cream freezes more easily. Once frozen solid, then thawed back to eating temperature, it tends to develop an oleaginous texture and have things like carrageenan unattractively (even if edible) oozing out of it. So don't count freezing ice cream as a feature -- it's actually a bug.
posted by dhartung at 11:49 PM on November 23, 2008

It sounds like your freezer is freezing to somewhere between 30F and 0F. This is cold enough to freeze water (i.e.: meat), but not really cold enough to make ice cream rock hard. It's also not really cold enough for long term storage, which is probably what you want for a chest freezer. Definitely measure the temperature. If it's above 0F, you might want to see if you can turn the thermostat down or have it serviced.
posted by Caviar at 8:00 AM on November 24, 2008

It means beef freezes at 29 degrees fahrenheit, and most ice creams freeze at 10 to 0 degrees fahrenheit, and the cheap extended medium temperature compressor in your domestic appliance just can't keep up (or it's a touch low on freon).
posted by vonliebig at 2:00 PM on November 24, 2008