Gold and Silver Leaf are both used to decorate foods, and have been so used for many centuries. Surprisingly, both are harmless as long as they are consumed as pure metals, though many silver compounds are poisonous. They are on the EC list of approved colourings, having the numbers E175 and E174. Usually they are applied in the form of very thin sheets known as gold or silver leaf. Narrow ribbons and powder are also sold. All are tasteless and odourless.
Gold leaf is made by rolling the gold into a foil, placing it between skins of vellum or intestines until a multi-layered sandwich is formed, and then hammering it until the gold is seen to exude from the edges. The gold is then quartered and the process is repeated until the leaf has attained the desired thinness, which is very very thin indeed. It is often sold in books of 25 leaves, separated by thin tissue. Released from the book it is a most wayward material and the handling of small pieces demands care. In An Ordinance of Pottage, an edition of the 15th-century culinary recipes in the Beinecke MS 163, there is a recipe (138) in which a sweet pie is ornamented with blanched walnuts, wetted with saffron water, and impaled on a pin or needle for ease in handling. The needle is held in one hand and gold foil is laid on
with that othir hond with a thyng made therfore, & blow theron esyly with thy mouth, & that shall make thy gold to abyde. & and so thu may gylt them over, and florich thy bakyn meat therewith.