Sterilise 2 x 250 ml jars by washing in hot soapy water or take straight from dishwasher, filling with boiling water, emptying and then placing in oven for 20 minutes at 140°C, 120°C fan, 280°F, or gas mark 1, then leave in oven until jam is ready. Washed lids should be sterilised with boiling water and then left to drain.