Dry Ice Frequently Asked Questions
What Is Dry Ice?
Dry ice is solid carbon dioxide (CO²). It has the unusual property of ‘subliming’, that is going from a solid to a gas without passing through a liquid phase and this is how it gets the name ‘dry’ ice. The product can only exist at -78°C and it maintains this temperature by sublimation.
The first published observation of dry ice was in 1835 by French chemist Charles Thilorier. He noted the formation of dry ice when a container of liquid carbon dioxide was opened.
In the UK liquid CO2 is a by-product of the fertiliser industry. It can be argued that the use of dry ice is not making a net contribution to global warming because the CO2 involved is being re-cycled; if dry ice was not made the CO2 involved would be released into the atmosphere from the fertiliser plant directly. In some other markets CO2 for dry ice is made by burning fossil fuels which is environmentally very harmful.
How Is Dry Ice Made?
Liquid Carbon Dioxide (CO2) is the source of all dry ice products. The liquid is stored at 20 bar and around -20°C. It is released through a nozzle to 1 bar at which point dry ice ‘snow’ is created. This snow is compressed and extruded at around 1500 psi to form pellets, slices and blocks of dry ice. The CO2 used is food grade and is non-toxic, it is the same chemical that gives drinks their fizz.
Dry ice density is around 1.6 g/cm3, however the bulk density is around 1g/cm3 – just like water.
The molecular weight of dry ice is 44.01.
How Do I Store Dry Ice?
Store dry ice in an insulated container - the better the insulation, the slower the rate of sublimation to CO2 gas. The best container is the polystyrene box that the dry ice was shipped in. Do not store dry ice in an airtight or glass container.The sublimation of dry ice into CO2 gas will cause an airtight container to expand, rupture or burst.
The CO2 gas occupies about 800 times the volume that the dry ice did! CO2 gas is heavier than air and will sink to low areas and displace air. At elevated concentrationsCO2 can be fatal as an asphyxiant.
For this reason always store dry ice in a well ventilated area - avoid unventilated rooms such as cellars, boat holds and walk-in freezers.
Note: you can store dry ice in domestic (non-walk-in) freezers provided the dry ice is kept in the polystyrene packaging. The dry ice will release CO2 gas whilst in the freezer however there is no risk of asphyxiation. The freezer will reduce heat transfer into the box and prolong the life of the ice. However do not store dry ice in walk-in freezers as there is a risk of an accumulation of CO2 which could cause an asphyxiation risk if the freezer is not used regularly.
Some surfaces left in direct contact with Dry Ice may be damaged by the extreme cold. Adhesives may become brittle and break. So please do not let dry ice into contact with kitchen tiles, or other surfaces which are susceptible to damage from the cold.
Is Dry Ice Safe?
Provided the safety guidelines are followed dry ice is safe - we ask that our customers follow the BCGA guidelines as a condition of sale. Please click here for our safety advice and guidelines.
What Is Dry Ice Fog?
When dry ice is added to warm water a dense white fog is immediately generated.The white fog is an aerosol of tiny water droplets just like fog created naturally. What’s happening is that the very cold dry ice is subliming from solid to the gaseous phase and bubbling through the water. In so doing the CO2 gas leaves the water container which has a substantial amount of moist air above it. The cold CO2 gas condenses water molecules in the air above the container leading to the formation of tiny water droplets which are so small they stay in suspension with the gas. The only difference between natural fog and dry ice fog is the presence of gaseous CO2 interspersed with the water droplets. CO2 gas is heavier than air and so tends to carry the white fog towards ground level creating cool effects! The fog will cover the ground, roll down stairs, and swirl when walked through. It will not rise into light beams like glycol type foggers and will not make a fine mist in the air like hazers. Dry ice fog has no odour, contains no chemicals, and leaves no oily residue.
How Do I Make Dry Ice Fog?
Consider using a fog generator – the next question “How is a dry ice fogger operated?” If you are looking to cover a large area, such as a dance floor, you will need 20kg of dry ice which will last for 8-10 minutes. Add dry ice to a container with hot water (50C) and the fog effect will be spontaneous. The fog effect can be halted if too much dry ice has been added to the water so chilling (and ultimately freezing) the water and reducing the humidity of the air above the container. To maximise the fog effect you need to use warm/hot water. If you want the fog effect to last for a prolonged period consider adding a source of heat to keep the water warm - the container could be a rice cooker or slow cooker on the lowest heat setting. Be careful - if you use the heater on a high setting thermal currents will send the fog into the air spoiling the effect. Candles will not work as the CO2 will extinguish the flame, after all CO2 is used in fire extinguishers!
How Is A Dry Ice Fogger Operated?
The fog machine is filled with water and heated with its built-in heating elements. When the water has reached operating temperature (two to three hours), the ice chamber in the machine is loaded, when fog is needed the pump is turned on and hot water is pumped into the ice chamber, immediately creating fog. The fan is turned on and the fog is blown out to the stage via a ducting hose.
How Do I Order Dry Ice?
You can place orders for dry ice packs and blocks on-line at www.chillistick.com. Our standard delivery days are Tuesday to Friday. For special requests, Saturday delivery and other quantities, please phone us on 0203 4329412.
Dry Ice How Long Does It Last?
It depends! 10kg can be consumed within minutes if added to sufficient hot water to create large scale effects. However, for smaller more subtle effects the dry ice can last for hours. We ship dry ice in thick polystyrene boxes and the ice will last for 3-4 days depending on how you store the ice. We recommend keeping the ice unopened in the packaging until it is required and to store the box in a safe cold place. Once ice has been used put the lid on the remaining product and place in a cold location.
Can We Put Dry Ice In Drinks?
Dry ice should never be placed into the mouth or swallowed. So as a rule dry ice should never be added to drinks to avoid any such risk. However, Sublime Products have created a new product called Chillistick which allows dry ice to be added to drinks providing a safety barrier between the drinker and the dry ice so creating great smoking effects whilst enjoying a drink safely. When dry ice is loaded into the Chillistick a majority of the gas will bubble to the surface and create the much-loved mist. A small amount of gas will dissolve into the liquid to create carbonic acid and effectively carbonate the beverage though not enough to cause any fizzing. The slight carbonation effect is enough to tingle the tongue and give a slightly bitter taste as found in popular soda waters. Dry ice will chill drinks and because it sublimes will not dilute drinks as does conventional water ice. It is cold enough to chill beverages without the use of ice. Hence dry ice will not water down or dilute drinks. The mist effect varies depending on the temperature of the beverage. The colder the liquid the slower the dry ice will be dissolved see our section on fogging. A hot beverage can produce spectacular results as the dry ice is rapidly dissolved. Typically the mist effect can last 3 to 5 minutes.
How Much Dry Ice Do I Need?
For presenting small items such as cakes, food and beverages our small 2.5kg pack is ideal.Please note that if you are looking for a subtle effect to enhance a food/wine presentation less is definitely more! If you wish to create a couple of large smoke effects for your guests then you will need the 10kg pack, and if you have a large space and want to create something memorable multiples of this are worth considering. As a rough guide 20kg of dry ice will produce between eight to ten minutes of fog and create a thick fog carpet.
Where Do You Ship Dry Ice?
We can send dry ice nationwide on a next day service to arrive with you Tuesday to Friday. We can also arrange Saturday services and timed arrivals by special arrangement.
What type of ice do you supply?
We provide food grade 9mm pellets and also rice ice. We can offer customers blocks and slices, however we would require a minimum of 5 working days notice.
Do you ship Frozen Goods?
Yes, we offer a full service for frozen or chilled shipping including pick-up, document preparation and small lot shipping nationwide.
If you would like further information please do not hesitate to contact the team on 0203 4329412.
How to use dry ice in the chillistick
The chillistick allows dry ice to be used safely in drinks and cocktails. The chillistick is filled with dry ice and then lowered into drinks when it immediately starts to bubble creating a thick water fog which looks cool in every way. The white fog is composed of tiny droplets of water - just like mists formed in nature. The mist spreads the naturalfragrance of the drink so that you smell the drink before you taste it!
Please read the safety guidelines for the safe use of dry ice. Open the dry ice box and cut the thick poly bag with scissors or knife. We recommend that you use gloves in handling dry ice. Using a scoop or glove remove a handful of dry ice and select one or two pellets which are 0.5cm or longer. If using gloves supplied with kit put both gloves on one hand - the air gap between layers will provide insulation.
NOTE: You will notice that there are some small pieces of ice and some dry ice dust, this is normal, these smaller pieces will keep the larger pieces in good condition, so put this dust back in the box and close the lid.
Hold the chillistick by the base of the handle and using gloves carefully add a piece of dry ice to the scoop end of the chillistick, using a finger push the ice so that it opens the plastic safety valve within the chillistick. Using a stirrer stick or glass rod push the ice through the valve into the body of the chillistick.
NOTE: The valve will be slightly stiff the first time the chillistick is used, you may find it easier to loosen the valve using a stirrer rod or small finger prior to loading with ice.
To check that the ice has been secured in the chillistick the rounded end of the stirrer rod will be engaged by the valve and it will be possible to hold the entire assembly by the stirrer rod. Pull out the stirrer rod and use. You can prepare chilllisticks up to 45 minutes prior to serve and in this case keep the loaded chillistick in the dry ice box. With practice it is possible to load the chillistick in about 5 - 10 seconds. Please see the video.
To create spectacular fog effects to enhance the back of bar area or the serving of food we suggest using a tall vessel to minimise footprint:
Fill the vessel with warm to hot water and add around half a cup of dry ice. The mist will flow down the jug and over the surrounding area. Positioning the vessel underneath a spot lamp will maximise the effect which will last for up to 5 minutes. The warmer the water the more spectacular will be the fog effect; as the water in the vessel gets colder the smoke effect will diminish. If you are serving food you may wish to consider adding essential oils to the water which enhance the food - vanilla for desserts for example. Your guests will smell these complimentary flavours so adding to the experience. Please contact us to discuss bespoke smoke designs.