Oxford Night Caps by Richard Cook (1860, p.30) — Oxford 1860
| 1 whole | lemon peel — juice from the peeling of a lemon | acid |
| 12 whole | egg yolk — egg yolks | base |
| 0.5 pint | gin | base |
| cinnamon — A small quantity. | other | |
| 1 whole | nutmeg — Grated. | other |
| 1 quart | strong ale — strong beer | other |
| 1 bottle | white wine | other |
| sugar — Enough to sweeten. | sweetener |
- Prepare the drink precisely in the same way as Rum Booze, using the stated combination of yolks, beer, wine, gin, spice, lemon-scented sugar, and sweetener.
Rumfustian sits in the overlapping territory between posset, flip, and wassail-like fortified ale bowls.
Its identity is mostly one of scale and intensity on top of the Rum Booze template.