Talmud Bavli Kereitot on the Preparation of the Anointing Oil

"This was the method used in preparing the anointing oil that Moses made in the wilderness: He would boil the hin of olive oil together with the roots of the spices - the words of Rabbi Yehudah. Rabbi Yose said to him: But there is not enough oil to even smear the roots with the olive oil, let alone boil the roots in it! Rather, how does one proceed? First they brought the spice roots and soaked them in water, then Moses removed the roots from the water and he poured oil on them until they were covered with a layer of olive oil, and the oil absorbed the fragrance of the spices. Moses then quickly removed the oil from the bowl and wiped off the oil still clinging to the roots, and deposited it all into a flask."

-- Talmud Bavli, Kereitot 5a