The measurement dash is often used for extremely potent or concentrated ingredients like bitters or Absinthe. The purpose of said ingredients is to enhance or complement the flavors of a cocktail and impart a deeper flavor profile to your drink.
Countless classic and contemporary cocktail recipes ask for a dash of bitters. -For the record, cocktail bitters really do make a difference, e.g., Angostura bitters in a  Whiskey Sour. Still, when it comes to measuring a dash, confusion arises.
The term dash has been appearing in cocktail books for ages; It's as old as mixology itself. At the same time, it is one of the least precise measurements in bartending.
Whichever cocktail you make, a dash of some ingredients can make a massive difference. Consequently, an "oversized dash" will make an even bigger difference and could quickly become overpowering. So it would be nice to have an idea of what a dash actually is, right?
What is a Dash?
A dash is more or less the bartending equivalent to what a pinch is in cooking. A dash of bitters is seasoning your drink like salt is seasoning your wagyu filet.
If you think about it like that, you can understand why the term is somewhat vague. Above all, it is a matter of taste if you use more or less seasoning or bitters. But since that's not a satisfying answer, let's take a closer look.
A dash is a minuscule quantity of liquid you cannot measure with standard measuring tools like jiggers or a bar spoon. Also, for all number enthusiasts, there is a defined measurement for a dash:Â
One dash equals as little as 0.92ml. Converted to oz, this would be 1/32 of an ounce or 1/8 of a teaspoon.
To explain the term further, you must know that bitters and other things usually dosed in dashes traditionally get stored in so-called dasher bottles. Those bottles only release a wee bit of the liquid they contain at once.
But the mystery isn't solved with the dasher bottles alone. Some advise that a hard and quick shake of the dasher bottle will release a dash, while others suggest a slow approach to let the liquid out of the bottle drop by drop.
How to measure a dash
Even if you know the numbers now, you cannot measure them. So standardizing the dash is really tough.
That, in turn, leads to slight differences in taste when different people make the same drink. But that is not necessarily a bad thing. Think of it as a part of your unique way of making drinks.
How you hold the bottle and measure your dash likely is different from others. Yet, as standard tools don't work for measuring a dash, there are some little helpers:
Dash measuring spoon
For cooking, there are those tiny measuring spoons that should help to measure a dash. But measuring with them is really hard as the liquid from the bitter bottles is not so easy to control. At least if all of the bitters should end up on that tiny spoon.
A way to measure a dash more consistent - Japanese dasher bottles
If you still feel unsure and don't have enough experience, you might search for a better way to measure your dash anyway. And I can understand that.
The plastic tops of the bitter bottles you can buy are usually more in the direction of not-so-precise. Luckily, there is a solution to that.
Some of the world's top bars also noticed the dash-gate and started acting on it. Many of them use only special dasher bottles, mostly Japanese ones.
These elegant little bottles are a lot more precise. Death & Co bar in New York experimented with them and found that one dash of a plastic-top bottle equals three from a Japanese dasher bottle.
My advice is if you're feeling unsure, get one of these dasher bottles. The dashes will be more precise and consistent. And consistency is an advantage when you're new to mixology and want to learn how everything works together.
What happens if my dash isn't their dash?
Even if you are a perfectionist, don't worry too much about the difference taste-wise. Despite everything, a dash is a small amount. And, as long as you only use a small amount, you won't ruin your cocktail.
Making cocktails is like any other craft you learn. It takes time and practice. If a recipe asks for a dash, you can use a Japanese dasher bottle and taste your drink. Then add another one and try again.
By experimenting, you will find the right way to apply your dash measurement.
Conclusion
The dash is a very imprecise measuring unit and nothing you can measure with a jigger or any other bar tool. Getting it 100% right requires some practice and experience.
But even if your measurement is slightly off, it won't affect the quality of the result in a significant way. Yet, if you want to make sure, use the tools mentioned above.