Straining is used almost every time a cocktail is mixed in a cocktail shaker, no matter if it has been shaken or stirred. It is a very simple technique, but there are a few tips and different methods that will help you get the cleanest drinks. Which you use will depend on the type of strainer and shaker you are mixing with, as well as the drink's ingredients.
Why Do We Strain?
A basic bartending technique, there are a few different reasons why we strain cocktails. The most obvious is when we don't want ice in the finished drink. Martinis and similar cocktails which are mixed with ice but served "up" fall into this category.
For drinks that are served over ice, it is generally preferred to strain out the old ice and pour the drink over fresh ice. This is particularly true when a drink is shaken.
Shaking breaks down ice considerably, sometimes reducing the cubes to half their size. While this dilution is actually desirable for the drink itself, too much water is not. The fresh cubes in the serving glass will last much longer than the shaker ice, helping avoid watered-down drinks.
The final reason we like to strain cocktails is to remove chunky ingredients. This may be bits of fruit, torn herbs, or whole spices that are not desirable in the final drink. They've done their job to flavor the drink and are no longer needed.
While cocktails like the mojito and old-fashioned are generally served with these solid ingredients, it's not the best option for every drink. Also, some drinkers prefer the strained version because it prevents the accidental mint leaf from getting stuck in their teeth.
Straining With a Cocktail Shaker
The three-piece cocktail shaker is the easiest to strain drinks from. The strainer is built into one of the lids, so there is no need for a separate tool.
When you use with this strainer, you want to get a firm grasp on the mixing tin. Place your forefinger and middle finger on top of the strainer lid to secure it ( the strainer lid can and will come off if you don't). Slowly tip your cocktail shaker upside down over the serving glass and let the drink pour out. Due to the smaller hole, give it a little shake to move the ice around and ensure you get all of the liquid.
Straining With a Boston Shaker
The Boston shaker requires a separate tool to strain because there is no built-in strainer. The majority of the time, you will want to use a Hawthorne strainer, but you may also find a julep strainer useful at times. It's not a bad idea to have both in the bar, though the Hawthorne is a better choice if you're going to choose just one.
Hawthorne Strainer: This strainer is very common to see in bars. It has a flat top with either two or four "thumbs" sticking out and a semi-circle of springs underneath. It is designed to fit snuggly inside a shaker tin to hold back ice and almost all solid ingredients, creating a clean, crisp cocktail in the glass.
To use the Hawthorne strainer, place it inside of the mixing tin with the coil facing down. Hold the strainer in place with your forefinger while grasping the tin firmly near the top. Slowly tip the tin over the serving glass. When the glass is filled, quickly return the tin to an upright position to avoid any spills on the bar.
Julep Strainer: Use this strainer when straining from the mixing glass of your Boston shaker because it tends to be a better fit. This is useful when stirring drinks because it is often recommended to pour ingredients into the clear glass part of your shaker so you can see what and how much you're pouring.
To use the julep strainer, place it inside the mixing glass with the bowl of the spoon facing out (it seems counterintuitive, but it should be upside down). Hold the strainer on the joint between the handle and bowl using your forefinger and firmly grasp the glass close to the rim. Slowly tip the mixing glass over the serving glass. When the glass is filled, quickly return the tin to an upright position.
Breaking the Shaker: This is a method of straining that some professional bartenders like to use and it doesn't require a separate strainer. Essentially, you are going to crack the seal of the Boston shaker and carefully pour the drink into the serving glass through the small gap you create between the two pieces of the shaker.
The trick here is to control the pour without letting any ice fall through the gap or force the two pieces apart, therefore dumping the entire drink. It requires practice and it's recommended to do so with water. Also, this method will not strain out any herbs or small solids as they will slip through the crack.
Some Boston shakers, like the Quick Strain Tins, have strainer holes built into the walls and make quick work of straining.
Double or Fine Straining
On occasion, you will come across cocktail recipes that suggest double straining, such as the watermelon cucumber cooler and French Quarter smash. This technique is often used when the cocktail is mixed using torn herbs and other small, solid ingredients that are not desired in the final drink. When double straining, you will run the drink through two strainers: one of those mentioned above and a fine mesh strainer.
To double strain, place your regular strainer in or on the cocktail shaker and hold a fine mesh strainer by its handle over your glass. Pour through both strainers into the glass, anything that made it through the first strainer will (ideally) be caught in the mesh.
If your mesh strainer is larger than the diameter of the glass, be sure to pour slowly so liquids don't splash over the rim.