I read, in one of the many things I’ve read recently regarding cocktails, that James Bond’s ordering of a martini shaken, not stirred, was his ordering the martini watered-down and being snooty about it. This shaking does. It also changes the taste and presentation of the drink.
I stirred my martini this evening instead of shaking it. It was much clearer, but also not as cold. It tasted quite different; still drinkable, but more clearly a blend of the gin and vermouth. I’ll confirm tomorrow, but it seems the presence of the vermouth is stronger when the drink is stirred.
The argument against shaking the martini distills thusly: it bruises the gin.
That’s not precise enough, so I call hogwash.
Another source I’ve read — please accept my apologies for the lack of citations, but I did not keep notes — held that shaking is just as fine as stirring as long as shards of ice do not survive in the drink. I’m fine with this explanation, and tend to shake my martinis rather than stir them, for two reasons: first, the diluted gin or vodka lets me drink more than one; second, the rough mixing of the ice and alcohol, whether vodka or gin, changes the taste to my preference.
On the other hand, it does fill the glass near to tipping.