Processing of soil in earth-based building materials suffers from a lack of a coherent knowledge base. This led researchers to adopt different soil preparation methods among countries and regions. This paper investigates the effect of the process and related energy used in the preparation of soils for unburnt hand-moulded earth brick. Impact made on the flexural strength, compressive strength, bulk density and volume shrinkage of the earth brick is evaluated. Two sets of bricks were moulded: one from manually mixed soils and the other from mechanically mixed soil. The related energy for mechanical mixing was calculated by measuring power consumed by the electrical mixer used, and its value was 6.6 × 105 Nm/m3. Results revealed that mechanical mixing induced an increase in flexural and compressive strength of 62.7% and 69.5% respectively. Bulk density slightly increased from 1.90 g/cm3 to 1.92g/cm3 and volume shrinkage reduced from 7.96% to 6.67%. Elastic modulus of bricks from hand mixed soils and mechanically mixed soils were 304.19 and 554.06 MPa respectively. A significant improvement in brick performance was observed when soil was mechanically mixed. This research also attempts to standardise a step in the moulding method of earth bricks especially in lab-controlled environments. With similar mixing energy, performance between earth bricks made with soil from different regions can be better compared. Repeatability of tests is also improved.