Why does my reefer have to be at -10?

Ok dumb question but bear with me here. I'm hauling frozen chicken nuggets. They had me set at -10 continuous. Frozen is frozen why would they not say set at like 20 or something? Reason I ask is met a guy at the loading dock say in summer frozen is frozen and he sets to 20 or 30 when he is driving to save diesel cost or something like that. I chuckled and went along my way. But it did get me thinking. Is frozen really frozen or am I missing something?

 

Set the temp as the BOL directs.
Set it at 30 degrees and you may have the load rejected, then lose your job.

 

Yes I'm well aware and don't plan on going stray from my BOl but was just curious if there's some scientific reason or something it should be -10. That's frigging cold haha

 

The customer, consignee, ordered it at -10 degrees.
Yeah, that's friggin' cold!

 

Mostly it's a cya thing. If they specify -10, then they are almost guaranteed it will make the trip frozen. If they say 20, and the random truck that shows up that's never been well maintained has a dodgy thermometer it may thaw a bit.
Also, they are likely using the carrier to finish freezing the product.

 

Usually when a shipper directs you to run a frozen load on continuous, it's because they're loading product that is significantly warmer than the set temperature they specify. They want you to freeze the product in transit... or so they think. It's best if you pulp the load (check the product temperature) so you know what you're dealing with.

If the product is at or below 0°, running -10° on continuous is a waste of fuel. -10° cycle mode will allow the box temperature to stay below 0° at all times.

Be aware that some brokers standard rate sheet specify all loads to be run in continuous mode. Yeah... not.

All this being said, I don't run any frozen load in continuous mode except for ice cream in the summer.

 

New reefer trailers are remotely monitored in the trucking company dispatch office, so if you're a company driver, do what the BOL has. If you're told to run on continuous, then do it. You're not paying for the fuel, the trucking company is and that's figured into the billing.
Owner-operators can do what they want.

 

As for why not 20 or 30, it's because 0° is considered to be the ideal food storage temperature that maintains quality while conserving energy.

Reefers set on -10° Start/Stop mode have a 6° to 8° spread between when the unit turns off and when it cycles back on. The box temp always stays below 0°

 

If the reefers are remotely monitored, the driver usually doesn't set anything, the company does it.

 

In a store. You'll have a freezer. Walk through that to the deep freeze. That is below zero. They bring food out of the deep freeze. Then into the freezer to thaw out. Only after it has thawed in the freezer will they bring it out to the floor.
I didn't work with it. Supposedly something about deep freeze much better?
If this makes you wonder. How about setting temp at 45f when it's below zero outside.