A group of us are planning a mid-winter Christmas feast in New Zealand during July. My contribution will be cooking the turkey using Nigella's Spiced and Superjuicy Roast Turkey recipe however I'm having a lot of trouble sourcing White Mustard Seeds (in both New Zealand and Australia). I have found Yellow Mustard Seeds but can not find anywhere that confirms if they are the same or interchangeable. Please advise if yellow mustard seeds are the same as white ones or at least can be used as an alternative?
White and yellow mustard seeds are the same thing. In fact the seeds are mostly a light tan in colour. When they are ground up they make the yellow mustard that most people are familiar with (sometimes some colour is added to give a very bright yellow). When whole they tend to be called white mustard seeds and used in pickles, relishes and brines.
There are two other types of mustard seed. Black mustard seeds originated in the Middle East and Southern Mediterranean, are very pungent and were often used as a treatment for respiratory problems. Brown mustard seeds are thought to have originated in the Himalayas and are not quite as strong as the black seeds. Both black and brown mustard seeds are used in Indian, Asian and Southern Mediterranean cooking but brown mustard seeds are now far more common as they are easier and more economical to harvest than the black variety. English mustard is usually made up from a mixture of white and brown mustard seeds.