From the same source
In spite of the tendency of glycerol to supercool, it can be crystalized by the use of seed crystals, or by cooling to -50 C or below and then slowly warming to about 0° C. Approximately one day is required for crystallization to be completed. The crystals are orthorhombic and very deliquescent.
I'm not sure if the seed crystals need to be glycerine, or what.
Did you see my note about Peanut oil having a melting point of 3 C, I found another source that says -2 C...so I think it might vary. I found several sources that say Grape Seed oil melts at 10 C, and I know that I've purchased some olive oils that were solid in my fridge, although some just get cloudy.
The beauty of oil is you can always cook with it.