Ice cream display & Sale freezer

[Rayin]

Dear All,
Can some one out there explain me what are the basics to consider in designing an ice cream display and sale freezer? why is it, even if the specified temperature is maintained, at times the content not getting hard, it is always wet? Should there be static and forced air cooling at the same time?
Thanks in advance
Regards
Rayin

[Electrocoolman]

Hi Rayin


at times the content not getting hard, it is always wet?


Are you expecting the unit to freeze ice cream down to temperature?
A display freezer will normally only 'hold' pre-frozen ice cream.
There is normally a 'load-line' which the product must be physically below.
I have seen some larger units with both bunker coil and wall evaporators, the bunker coil ensure the air above the ice cream is well cooled.

[davej]

Electrocoolman is right the product has to be below the load line, and also most ice cream thesed ays is soft scoop and wont get hard.
you should also consider if it is an open top merchandiser the amount of air changes, eg if there is a large draft of warm air constantly passing through giving too many air changes

[Toolman]

We would like to help but ......
Did you build this system up or buy it in from a manufacturer ? If you built it did you guess ?
We need to know - What size is cabinet ( dimensions ? ) , is it open top or front , how many doors , are they glass triple glazed ?
What is the Unit capacity and Evaporator size , model numbers , gas type , suction temp ? etc etc

[Samarjit Sen]

Hi Rayin,

Ice Cream is made at a temperature of -5oC and then the same is then put in a hardening tunnel or a chamber having a temperature of -35oC to -40oC. The faster the hardening the better is the quality of the Ice Cream. Generally it takes 3 to 4 hrs to harden. Ice Crean starts hardening from -13oC and is completely hardened when the core temperature reaches - 25oC.

The subsequent storage temperaure is -28.4oC. The freezers are supposed to maintain a temperature of - 25oC to -28oC so that the core temperature remains at - 25oC. There are times, when the manufacturers does not harden the Ice Cream to the desired temperature, in such case you will have problem in storage, where it will be soft. For hardening you require air blast, but not for storage.

In case your Freezer temperature is within the specified limit and even then the Ice Cream is getting soft, you must contact the manufacturer. In a way it is a manufacturing defect.

Anything more, please feel free to write.

[suny]

I certainly agree with all the views of Mr. Samarjit. As I am an Ice cream manufacturer, I would like to add some more to this thread.

1. Did you design this display unit?
2. Is it compatible for Middle Eastern temperature conditions? (High ambient Temp)
3. What is the input temp of ice cream?
4. What is the period taken to sell these ice creams from the display unit?
5. What is the fat content of the ice cream?

If you could answer these I would be able to help to overcome your problem to a certain degree. Furthermore your problem will occur due to improper manufacturing process.

1. Improper homogenization taken place.
2. Improper balancing of the ice cream mix to absorb the available fat.
3. Not frozen to -35 deg C with in 4 hrs from production allowing ice crystals to form.
4. Excess use of Emulsifiers compared with stabilizer.
5. Not properly aged etc.
6. High overrun.

Suny