The FDA recommends a freezer temperature of 0˚F (-18˚C). Warmer temperatures risk bacterial growth and quality problems. But what are the reasons not to set the freezer colder? My Bosch freezer can be set as low as -8˚F (-22˚C).
The only downsides I can see are increased electricity usage, increased thaw times during food preparation, and more wear on the freezer compressor. But advantages include colder ice cubes and faster freeze times for new items. Are there any other reasons not to set my freezer to the coldest setting?
Best Answer
One possible consideration is that some frozen desserts (most notably ice creams and sorbets) can be very difficult to scoop if your freezer is too cold. Optimal serving temperature for ice cream is between about 5 & 10°F (-15°C & -12°C); colder freezers may result in difficult scooping and/or needing to leave the ice cream out to thaw.
The proposed advantage of "colder ice cubes" is relatively small, because the vast majority of heat absorption by ice (in a drink, say) is due to it thawing. To put some numbers on it, every gram of frozen ice absorbs about 2.1 joules of heat energy when it warms up by 1°C. In contrast, that same gram of ice absorbs 335 joules of heat energy when it thaws into liquid water. If you run the numbers, this means that ice at -22°C will only absorb 2-3% more heat from your drinks than ice at -18°C.