Hellobee Boards

Hmmm. That’s a good question. The milk is going to go in at fridge temp tho. And the surrounding temp is obviously fridge temp, so my hypothesis would be that it stays around that temp. The only thing at room temp would be the cup. Do you have an instant read thermometer to test?

Otherwise you could store the cup empty in the fridge overnight and pour the milk in the AM before you put it in the lunchbox.

I use an ironflask with water for myself... I fill it at night and just leave the lid off in the fridge. I bring it to work in the morning and it stays cold well past noon.