Having discovered the joys of the 鈥溾�� (vodka mixed with apple juice, cider or apple liquor) I have a question. The garnish is a slice of apple and a Maraschino or glac茅 cherry on a cocktail stick. If the cherry is at the bottom of the stick it floats in the appletini, but with the apple slice at the bottom it sinks. Why? Surely the buoyancy of the two items combined is an absolute and their orientation should make no difference. I shall leave it to the imagination as to the number of 鈥榯inis consumed before this anomaly became a burning topic of conversation.
鈥� Ethanol acts as a wetting agent, so in an alcoholic drink the submerged slice of apple holds too little air to float the non-buoyant, sugary cherry. The assembly will thus sink, though if you add soda, enough bubbles might attach to the apple to make the whole thing float again.
Human sloshing complicates insights after the fourth glass of appletini, but buoyancy is a more complicated affair than density considerations might suggest. For example, a boat that is seaworthy might sink if capsized.
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Try dropping a clean, dry pin or razor blade gently onto a glass of still, pure water. Dropped endwise the object sinks; the metal is too dense. But surface tension will support the item if you gently drop it flat onto the fluid, especially if the metal is lightly waxed or oiled.
The behaviour of your appletini garnish is similar in some ways. The waxy skin and the broad shape of an unpeeled slice of apple on the surface of the drink can resist both the wetting and the shipping of fluid over the edge of the slice.
The stimulation of considering this question鈥檚 complications should mitigate the brain-addling aspects of appletini, though, sadly, not to the extent of fully reversing them.
Antony David, London, UK
鈥� Surface tension effects probably account for the observations. If the buoyancy of the cocktail stick assembly is nearly neutral, a flat slice of apple, when uppermost and level with the cocktail surface, may provide a sufficiently long perimeter for surface tension to hold the assembly up. The spherical cherry in the same position has little or no perimeter on which surface tension can act. The coating on the cherry may also reduce surface tension.
Try replacing the apple slice with a small ball of apple and see if the stick now sinks even with the apple uppermost. If this experiment fails, the cocktail may have aged, so drink it and try again with a new one鈥�
Paul Gladwell, Northwich, Cheshire, UK