Quote:
Originally Posted by shlacm
hmmmm... I'm curious about the dry ice method... seems like it would "burn" the tomatoes (or strawberries) if it came into direct contact... Did you ever try it?
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No way it would burn the berries. My company sells liquid nitrogen to shrimpers - they freeze the shrimp right on the boats. Considering LIN is at -196 deg Celsius and solid CO2 is at -78 deg Celsius, I can't see a problem.
It is known that liquid nitrogen produces a superior frozen product as it flash freezes foods retaining more moisture and not giving time for ice crystals to form which pierce cell walls and degrade the food. However it is more expensive than "mechanical" refrigeration (like using a conventional Freon type freezer with a compressor)
Just think about it - typical fruit goes in at room temp - 25 C. Normal freezer is 0 deg C. We all know from basic engineering that heat flux is proportional to delta T - that is why it costs more to heat your house in the dead of winter than a cool fall day.
Conventional freezer - delta T is 25 C
Dry ice - delta T is 105 C
LIN delta T is 225 C
Thus LIN has the capability of freezing 10x faster. I make ice cream in 5 minutes using LIN.