Before you start: Sterilise 4 x 280 ml (9 oz) jars and lids by washing thoroughly in hot soapy water (or take straight from dishwasher), fill jars with boiling water, empty and place on a baking tray. Bake in a preheated oven at 140°C for 20 mins and keep the jars there until ready to pot up. Place lids in a bowl and pour over boiling water, use tongs to lift out and drain on a clean tea towel or draining rack.