Drinking Cups and Their Customs by Henry Porter and George Roberts (1869, p.47) — Drinking Cups 1869 German recipe

3 lemonlemon juice — juice of lemonsacid
1 pintarrack base
1 lemonlemon peel — lemon rindbase
1 bottlerum base
1 quartcold water dilution
1 quartboiling milk other
0.5 poundloaf sugar sweetener
  1. Combine lemon rind, lemon juice, rum, arrack, sugar, and cold water; when the sugar has melted, pour in boiling milk, cover closely for four hours, and run through a bag until bright.

Source labels this a German recipe and says it should be quite bright.