The Shewbread in the Bible was made with sprouted grains (Ezekiel 4:9), where because it was left to naturally proof, it would produce ergot on the barley, and so was psychedelic; this is where the Shewbread was boiled, then baked - to neutralize the ergot poisoning.

This is similar to Kykeon, that the ancient Greeks drank for enlightenment at Eleusis.