Lamb’s wool is a traditional English drink which was popular from the 16th to the 19th centuries. It consisted of beer, heated, sweetened and spiced. Then the soft, fluffy pulp of baked apples was mixed in – presumably leading to the drink being so-named.
Samuel Pepys mentioned the drink in his diary on 9 November 1666:
Being come home, we to Cards until two in the morning; and drinking lamb’s wool, to bed.