Fun- density question? ethanol, sugar syrup, water?

Question

Why is it that when you make layered cocktails you add the densest liquid LAST?

so it THEN goes to the bottom? isnt that counterintuitive? like in tequila sunrise you add grenadine last that goes to the bottom, in a bellini you add peach juice last, WHY?

but shouldnt it just stay at the bottom if you put it in FIRST THEN add something less dense?? i mean, when making a pyramid you dont put the heaviest thing on last so it sinks to the base?? you put the heaviest thing down FIRST, no?

oddly enough, if you put the heaviest down first, as in grenadine in a tequila sunrise, when you put the lighter things on top it all mixes together so you dont have the same effect..

Answer 1

Putting the Densest last I think minimises mixing.

I remember doing a fun experiment to show Universal Indicator colours.

I would 3/4 fill a 50 ml graduated cyliunder with 2 M NaOH

Then CAREFULLY pour conc sulphuric down the side of the cylinder with minimum of motion.

Leave two days and you should see a gradation of colours

Answer 2

Probably INERTIA. You pour in a liquid and its inertia will keep it moving downwards.

Thus if you pour a liquid onto a more dense one, it will flow through it, and then back up again causing the two to mix.

If you pour a  liquid onto a less dense one, it will flow through and stay at the bottom.

Answer 3

it probably has something to do with the drinks not mixing... in the tequila sunrise if you added grenadine first ... it would just sit at the bottom and you'd be tasting every layer individually instead of a mixture.  

Answer 4

You will notice that the 'heavier' substance is added very carefully down the inside surface of the glass.

The 'Adhesive' forces of the thicker fluid between it and the glass is greater than the 'Cohesive' forces between the lighter ingredients.

This causes it to stay in contact with the glass as it 'slides' slowly down beneath the lighter ingredients.