I'm dropping a whole wiki tonight with the design of my offgrid zero-battery solar powered fridge.
Oil melt point is variable
Oils are made up of different fatty acids that have different melt points
Plant variety & growing conditions effect the proportions of different FAs
Methods used to extract the oil also effects the amount of different FAs
Oils are sometimes further processed to give desired properties
Eg. rape seed cooking oil is winterized (cold filtered) to take out any FAs that would solidify in a fridge as cloudy oil in a fridge is apparently disturbing