Dry ice is a great way to create a cool fog effect that can be used during halloween or parties and it's also commonly used to make exciting cocktails.
You place a small piece of dry ice into the drink and the gas from the dry ice cools the air above the drink making a fog appear directly above the drink. But how long should you expect this dry ice fog to last in your drink?
Dry ice typically lasts 2-3 minutes in a small drink or cocktail but can last up to 5-15 minutes if the drink starts out warmer or has a larger volume. Drinks starting cold or with less volume produce fog for a shorter period of time.
While this answer gives you a good timeframe for how long the fog will ask I also want to go into more detail explaining what the fog effect actually is and what affects how long the fog will last.
I'll will also give you some tips on how to make the fog effect last longer.
What Happens When You Put The Cube In Your Drink?
The dry ice that you see in your drink is actually condensed water vapor.
This is a big counter intuitive as you think it's the gas from the dry ice but this gas is actually invisible carbon dioxide gas.
As the cold gas escapes it cools the water vapor in the air directly above the drink causing it to condense into fog which is what we see.
The dry ice cube goes from a solid (the ice cube) to a gas when you put it into your warm drink. This process is called sublimation.
Because dry ice is so cold -109ºF (-78ºC) putting it in a drink makes the dry ice disappear more quickly and produce more gas which helps with the fog creation.
How The Fog Is Created
As the bubbles from the water vapor escape from the glass, it cools down the moisture in the air and condenses the vapor into fog.
The fog then drops to the floor as it becomes cooler than the air around it.
Why The Fog Ends
The fog is created from a temperature difference between the dry ice and the water vapor in the air. The warmer the drink the more water vapor in the air above it.
As the temperature difference gets less and less, and your drink starts cooling down to near freezing temperature there is less moisture above the drink thus the cooling effect starts wearing off.
Safety When Dealing With Dry Ice
Dry ice is safe to have in your drinks as it sinks to the bottom of your glass, and once it is fully dissolved it is completely safe. However, there are some things to keep in mind, the biggest being NOT TO CONSUME THE DRY ICE!
These safety best practises are:
● Don’t keep it in a sealed container.
● Keep it away from kids.
● Don’t consume it in its solid form
Consuming dry ice in its solid form can burn the mouth, esophagus and stomach and can even lead to internal bleeding. Learn about the dangers of dry ice.
Be sure to let your guests know that dry ice should not be drunk or eaten and should remain in their drink. Let them know the dangers so they are careful and don't drink it by accident.
What Influences The Duration of The Fog Effect?
Let’s take a look at what plays a role in cutting the length of your ice’s fog effect short.
As you may recall, the fog effect is caused by a temperature difference between the dry ice and the water vapor above your drink.
Hotter drinks create more water vapor (think of boiling water into steam).
To keep dry ice fog going you need a constant supply of cold dry ice gas and a constant supply of water vapor above the drink.
As the dry ice disappears or the drink becomes too cold then then fog effect can stop.
So, the preceding factors that we will take a look at all have something to do with this temperature difference, which we’ll explain.
The Size of The Glass
Smaller drinking classes will cool down quicker than larger drinking glasses.
The Time To Cool
This is because there is less liquid to cool down in a small drinking glass than there is in a larger glass.
The Amount Of Ice
Another reason this could arguably be the case is because less dry ice can be placed in a smaller drinking glass.
Both of these reasons result in a quicker decrease in the length of the dry ice fog.
The Amount of Dry Ice
We mentioned that smaller drinking glasses lead to less fog, and that one of the reasons was because less dry ice could be placed in your drink, when compared to larger drinking glasses.
The more dry ice that you have in your drink, the colder your drink will get faster.
However, having too little dry ice can lead to not enough cold gas to cool the air or the dry ice could run out too quickly which can also lead to the fog stopping.
The Temperature of The Water Or Liquid
The temperature of your drink also plays a role in how long the dry ice fog will last for.
The warmer the drink the more water vapor at the top so the more fog that can be created.
The warmer the drink also means the longer it'll take until the drink gets so cold it doesn't have enough water vapor for fog.
So generally speaking the warmer the drink the longer the dry ice fog will last for.
However, warmer drinks melt dry ice faster so if you don't have enough dry ice the warm drink can cause your dry ice to disappear too quickly.
So there may be a rapid burst of fog in the beginning but it will be short lived.
To counter this you can just use more dry ice in the drink. It really is a balancing act.
How To Make The Fog Effect Last Longer
Let’s take a look at a few ways that you can make the fog effect last longer with your drink.
Better Ratio Between Your Drink and Dry Ice
This takes a bit of tweaking and a bit of trial and error to get right.
Too much dry ice compared to liquid in your drink will make your drink cool down too quickly. This means that the fog won’t last for long, or won’t be large enough to create that fog effect that you’re after.
Too much liquid in your drink compared to dry ice might lead to not enough sublimation and a disappointment of a fog effect.
So how can you make dry ice fog last longer in your drinks?
1. Add More Liquid To Your Drink
If your fog effect is starting to wear off but you still have a decent amount of ice, then it may be a sign that your drink is cooling down.
To keep the fog going, top up your drink with more liquid. Doing this will warm up your drink a bit and increase the water vapor amount a bit, resulting in longer lasting fog.
2. Start With a Larger Drink
Drinking out of a bigger glass with more liquid will help your fog effect last longer.
This is because more liquid means that it will take longer for your drink to cool down, meaning that the fog will last longer.
3. Replace Lost Dry Ice
If all of your dry ice has melted, then your fog will stop no matter what the temperature is of your drink.
If the fog effect has stopped, then check if you have any dry ice in your drink left. If not, top up on dry ice and the fog effect you love will start again.
4. Time Everything
Not really a solution to keep your fog effect lasting longer, but definitely a way for you to show it off for longer.
Timing is everything when working with dry ice, so only pour your drink when all of your guests are ready to experience the awesomeness that is your foggy drink.
Pour it too early and the fog effect will happen but your guests will miss it.
Something Simple To Remember
Dry ice fog can last up to 5-10 minutes. It needs to be in a warm drink to create the cool fog effect. A tip to remember is that the dry ice fog effect lasts shorter in small drinks and longer in large containers.