The present invention discloses methods for artificially splitting nuts in a manner that ensures that the nuts split in the same manner as naturally split nuts. The methods include placing a batch of closed-shell nuts into a water filled vessel, sealing it, and reducing the pressure inside the vessel by removing air. This also causes air to be removed from inside the nuts. The air pressure in the vessel is then normalized, causing the air removed from the nuts to be replaced with water from the vessel. The nuts are then promptly transferred from the vessel and exposed to forces that cause the water inside the nuts to rapidly expand, creating internal pressure that forces the shells to split open along the longitudinal suture of the nut. The internal pressure can be created by the application of microwave radiation on the nut, thereby turning the water within the nut into water vapor, or by subjecting the nuts to a rapid decrease in temperature, thereby causing the water within the nuts to freeze and creating the internal pressure required to split open the shell of the nut. An alternative embodiment provides methods for completely splitting partially-split nut shells.