Themes include religion, identity, community, and the effects of colonization.

From the dawn of civilization, religion has helped man to understand his relationship with God. The Wine of Astonishment recreates a community's struggle to worship in a manner meaningful to them. The Spiritual Baptists at Bonasse incorporate elements of African cultural practices in worship. They derive spiritual comfort and a sense of identity from loud singing, clapping hands, the sound of drums, and spirit possession sessions. The modest hut where the Trinidadian Baptists gather to worship also serves as a community center.

In 1917, the British colonial government of Trinidad and Tobago rejects Baptist worship, deeming it noisy and barbaric. They pass the Shouters Prohibition Ordinance that prohibits worship in churches of the Spiritual Baptists. The law enforcement agencies harass, assault, and arrest those who attempt to worship secretly. The novel spans a period from the Second World War to the lifting of the ban in 1951.

Eva, the narrator of the story, describes the effects of the oppressive law and the people's struggle to hold on to their identity.

The primary theme is that of how colonization affects the peoples being colonized. For instance, their religious practices and even sports become subordinate to those of the colonizers--one reason colonizers are seen as oppressors. In the end result, after passing through the education system and moral value teaching systems of the colonizer, Lovelace contends, the colonized people have a deeply instilled perception of their own worthlessness and insignificance.