Green asparagus is the most popular variety in Australia. It derives its colour from the process of photosynthesis as the spear emerges from the soil into direct sunlight. Thick, medium and mini spears are available. Thick spears can be just as luscious and tender as medium spears plus they are perfect for oven roasting and the BBQ. Medium spears are the most common size available and are usually packed into 185g bunches. Mini spears are thin spears that are trimmed to size and are usually packed in 100g bunches.
Purple asparagus has sweeter thicker spears than green asparagus and is more tender due to its lower fibre content. It also has an interesting fruity flavour. The purple colour is due to anthocyanins (potent antioxidants), which are the same naturally occurring pigments that give blueberries their purplish blue colour. Limited supplies of purple asparagus are usually available from mid October to mid December.
White asparagus has long been considered a delicacy in Europe and has been grown in Australia in the past. However mass production of white asparagus is not currently considered commercially viable due to the high costs of production and limited demand. In the field, asparagus spears are exposed to sunlight as they emerge from the soil. The spears first turn pink and later, the familiar green colour. To produce white spears, asparagus needs to be grown in the dark. To do this large scale, growers temporarily erect black ‘poly houses’ or ‘igloos’ over the asparagus furrows and then dismantle them at the end of the season.