Seville orange

A bitter orange grown in the Mediterranean region. The Seville orange has a thick, rough skin and an extremely tart, bitter flesh full of seeds. Not an eating orange, but very popular for making marmalades and liqueurs. Also popular with duck because its acidity helps counteract the fatty flavor. The Seville orange season is short (Dec-Feb), so it's best to make enough marmalade for the whole year while they're available, but Seville oranges do freeze perfectly well.