Alpha lactose monohydrate is commercially produced using batch cooling crystallisation. The crystalline product usually has median size in the range of 100 to 300 micrometres, tomahawk-shaped crystals and less than 5% of the lactose content in the beta form. For some special applications in food and pharmaceutical products, it is desirable to reduce the lactose median crystal size to less than 20 micrometres, but the use of size reduction equipment will damage the crystal shape and form undesirable amorphous lactose. Beta lactose isomer, which dissolves more rapidly in water and is initially sweeter than the alpha form, requires crystallisation temperatures above 93.5ºC and a more complicated crystallisation process. In a sophisticated technique referred to as extractive crystallisation, a second miscible volatile solvent such as alcohol is added to the binary system lactose-water to reduce the solubility of lactose and hence “push” the crystals out of the aqueous solution. Our research suggests that using ethanol as the second solvent can produce needle-shaped crystals having the lowest median size of 8 micrometres, and beta lactose content up to 60%. On the other hand, using two immiscible solvents, one non-volatile and one volatile, such as by adding ethanol to the ternary system, lactose-water-glycerol, can make large needle or plate crystals with beta lactose content up to 80%. This work also generates for the first time two triangle diagrams comparing the equilibrium ratio of beta over alpha lactose anomers in the two ternary systems mentioned above.