Among the items associated with the services in the mishkan accounted for in Parashas Tetzveh is oil. The type used for the menorah is described as "zach katit lemaor" clear of pressed [olives] to illuminate. My grandfather quotes Menachos 86a "zach katit lemaor ve'eyn ze katit leminchos." The stipulation for pressed oil was only for the oil used to light and not for the oil used for meal offerings. Then he cites Midrash Tanchumah 6 that says what a person who has both better and worse oil typically does is use the lower quality one for light and the better one for food, but in the Tent of Meeting and in the Temple, they did the opposite, using the clear beaten oil for the menorah and the inferior one for minchos.
The reasoning is this, my grandfather explains. The menorah symbolizes chochma- as Chazal indicate in the reccommendation for one who wishes lehachkim to be yadrim, that is to face the south where the menorah stood. The idea is to bring the Divine light into the world. The minchos were for eating and to raise the physical, which is also a good thing, but not the main thing. One has to distinguish between the essential and the secondary, and that's the lesson of the quality of the oil used for the two.