This post is a companion to the Mixing Methods post.  That one deals with the practical aspects of the various methods we use to make cocktails.  This one deals with the theory and the science underpinning those methods.  Both start with a single question:

When we mix a cocktail, what are we actually trying to achieve?

At first this question may seem a little ridiculous.  Is it not self explanatory?

No, it isn’t.

It’s true that when we mix a cocktail we are aiming to merge a group of separate ingredients into a new whole.  But what specific effects are we trying to achieve in order to accomplish this?

Dark and Stormy

Properly Homogenized

I’d argue that there are three primary effect we are attempting to achieve: homogenization; chilling; and dilution.  We’ll go over each in turn, but then also consider some of the more minor or situation-specific effects we are also attempting to achieve.

Understanding precisely what you’re trying to accomplish is important.  It will allow you to choose the correct method in each case and work efficiently.

Homogenization

When we mix a cocktail our primary desire is to homogenize its liquid components.  To achieve the same consistency throughout the drink.

This is not a matter of chemistry.  We are not trying to cause a chemical reaction between the drink’s various components.  We are simply trying to mix them.  This makes it pretty easy in most respects.

Floated Long Island Iced Tea

Poorly Homogenized

As an example, consider a simple cup of coffee.  I’ve got some filter coffee from a pot, some milk and some sugar.  Homogenizing these ingredients is child’s play, and requires no special knowledge or equipment.  I pour my coffee into a cup, add some sugar, pour in some milk and stir.  The sugar dissolves with ease, and along with coffee and milk forms a new liquid with a single consistency and taste.

In a similar manner it is often enough to gently stir or agitate a cocktail to achieve this same level of homogenization.  But sometimes more forceful methods are required.  The amount of force needed often dominates the mixing method used.  For example, more force is needed to properly mix in a thick double cream than a watery cranberry juice.

Also it should be noted that certain cocktails actively seek to avoid a complete homogenization of their ingredients.  This is usually so that separate flavours can be presented to the palate to alter how the cocktail is perceived.  But these are only minor exceptions to the general rule of thumb.

Chilling

However, unlike for most coffees, the vast majority of cocktails are served ice cold.  The reason for this is simple – they generally taste better cold.  Why is this the case?  There are three factors at work.

Ice

Ice

First, colder drinks tend to be more refreshing, which is often what you’re aiming for in an alcoholic beverage.

Second, low temperature helps to mask the harsh bite of alcohol, making it more palatable.  For example, compare drinking a shot of vodka from the freezer against one at room temperature.  The former goes down smoothly.  The latter not so much.

The third relates to what temperature actually is.  It is the speed at which the individual molecules of a substance are moving.  The slower they move, the more time they have to interact with other molecules.  Like the chemical receptors which provide us with our sense of taste.

This may seem like an esoteric argument, but we can literally taste the difference.  A warm cocktail may taste alright.  But when cold, suddenly the flavours open up and hidden depths are revealed.

However, it should be noted that sometimes the reverse is true.  Sometimes the cold is excessive, numbing our senses.  Some drinks require a greater temperature to open up.

Brandy Baloon

Brandy Baloon

Brandy is an excellent example of this.  The appeal of a quality brandy lies not just in tasting the liquid, but in simultaneously inhaling the vapour given off by that liquid.  This is why the brandy balloon (or snifter) is designed the way it is: its short stem and wide bowl encourages you to hold it in the palm of your hand, allowing your own body heat to warm up the liquid; and it is curved to a narrow lip to direct the vapour towards your nose as you take a sip.

Dilution

The final major aspect of mixing drinks is diluting them.

Quite often dilution is a desirable effect when making cocktails.  Without dilution, many cocktails would be too strong for most of us to drink.  All our recipes would be incorrect.

But in some cases, dilution is something to be actively avoided.  This is often the case for Alcoholic Powerhouses such as the Manhattan or Dry Martini.  Those are supposed to be potent.

Our primary method of chilling cocktails is the application of ice to them.  The dilution caused by the melting of this ice becomes a trade off that we simply have to live with.  You want a drink cold, you accept that it will be diluted in the process.  And you plan accordingly.

I go into the science behind this trade off and its ramifications in far greater detail in my post on the Thermodynamics of Ice.

But in order to give you a rough rule of thumb I performed an experiment.  I took exactly 100ml of an average cocktail at room temperature which was ready to shake.  I filled it with ice and shook it for about twenty seconds – until it felt uncomfortably cold in my hand.  Then I double strained it out and checked its new volume.  It was now 153ml.

So, following a typical mixing method with no attempt at pre-chilling resulted in a 50% increase in volume.

Mojito

Mojito

Clearly the dilution of a cocktail that results from chilling it to an ice cold temperature is a major factor in its final consistency.

Other Effects

Finally, when mixing cocktails we sometimes want to achieve specific aims.  These aims will determine what methods we use.  I’ll go over them more in the Mixing Methods post.

To begin with, pretty much anything I might want to serve over crushed ice, such as a Mojito or Caipirihna, I would choose to Build.  That is, to make it in the glass in which it is served.  The large surface area of crushed ice compared to regular ice cubes means that chilling and dilution occur very quickly.  So it makes little sense to shake a cocktail, diluting it significantly in the process, only to further dilute it by straining it over crushed ice.

But once I have all my ingredients in my glass with my crushed ice I cannot homogenize them by shaking or a gentle stir.  Instead I need to Churn the cocktail.  Think of this as a vigourous stir, but with my bar spoon moving vertically more than horizontally.

Whiskey Sour

Whiskey Sour

Alternatively, if I want to produce a froth on top of a cocktail then I really need to shake it.  Now when making say an Espresso Martini or anything with Pineapple juice in it like a Singapore Sling, it is enough to simply shake it hard to produce a froth.  However, when using egg white to create a froth, as for a Whiskey Sour, I would need to Dry Shake it first before making my main (wet) shake.

Little Lemon Fella

Little Lemon Fella

Occasionally, you might want to Layer a drink.  To float one layer on top of another.  This technique is especially used for shooters, but also occasionally for creating Sweet and Sour drinks.  The use of a bar spoon and an understanding of viscosity is what counts here.

Finally, if you really have to, you can Blend a cocktail.  This involves placing all the ingredients and ice into a blender and letting the machine work its magic.  Depending on how much ice you added this can result in something with the consistency of slush up to a sorbet.