I've used a thermos to bring milk to work, it lasts a good while. I only wish I had bought a bigger one than 16 oz. (heads up)I've been trying to figure out how to carry milk shakes to work. Do you put the blended shake in the fridge or are they ok to be left out at room temperature for 4-6 hours? I'm surprised that a mix with OJ holds throughout the day though ! I'll try this with baking soda to see if the curdling stops.