Each January and February British cooks hunt out the season’s supply of Seville (or bitter) oranges (Citrus aurantium var. amara) to make marmalade. During the making the bitterness is tempered, though not overwhelmed, by plentiful sugar while the rind that carries the embedded oil glands is retained, as either ‘thick’ or ‘thin’ cut.
Spanish growers are not permitted to wax Seville skins (sweet orange skins are not so lucky), so it is safe to use them in your marmalade, infusions and other preparations. The skins are a digestive stimulant that also eases flatulence and calms nausea or morning sickness.
The best orange juice is no doubt that which you squeeze for yourself from oranges you know are organically grown. This way reduces the chemical additions of frozen concentrate orange juice (FCOJ), the form in which most commercial orange juice from sweet orange (Citrus aurantium var. dulcis) is purveyed.
Orange is a perfumier’s friend: the flowers yield neroli oil, the leaves give petitgrain essential oil and the rind of north Italian oranges goes into bergamot oil and thence Earl Grey tea. Eau de cologne is originally an eighteenth-century German facial rinse, made from bergamot and neroli oil, plus rosemary leaves, and distilled in grape juice.