Common perception of cocktails is that they are strong, with a high percentage of alcohol. But there has certainly been a shift within top bartenders looking at non-alcoholic and lower alcohol drinks. The focus is really on flavour, complexity and, in my opinion, balance of the former is the most important aspect by far.
An important thing to note is that it is hard to brand all cocktails with the same brush as there are many different types with a host to techniques and processes to make them. I won’t bore you with the techniques today, but they often play a pivotal role in the outcome of the drink’s alcohol by volume. Classics such as Old Fashions, Martinis and Manhattans are short and strong, often around 25% ABV. Which is pretty high. Think of that in comparison to a glass of wine around 13%. The alcohol flavour itself will be prominent. These strong drinks tend to suit end of the evening.
Contrast this to Tom Collins or a Bloody Mary, which will be less than 10% ABV. It all comes down to occasion and the point in which you are looking to enjoy each drink. On a sunny early afternoon in July, in the park with friends, I would struggle to drink an Old Fashion. In fact, I would rather not have a drink at all. By contrast, a Tom Collins, clean and citrus lead with delicate botanicals of from the gin, would be perfect – long and refreshing.
So yes, cocktails can be non-alcoholic, but they can also be 25+% and there are no set rules of how strong they should. If you enjoy strong cocktails, then the short classics that I mentioned before are for you. But more often than not, the drinking occasion will call for drinks less than 10% ABV, that can be sipped over a long period of time and that is fully personal preference.