Historical clue formulations

• Top of a latte — 2026-02-15
• Bubbles — 2025-10-18
• Lager-head? — 2023-04-30
• Foam — 2021-02-08
• Top of an espresso — 2020-04-15
• Foam — 2013-03-25
• Latte topper — 2010-05-30
• Possible sign of rabies — 2009-11-02
• Insubstantial stuff — 2005-04-12
• Foam — 2004-12-13
• Head — 2004-11-20
• Suds — 1996-05-08
• Triviality — 1996-04-10