Imagine it being a hot afternoon and you just finished working outside in the hot sun. You decide to cool off with a cold beverage. Much to your dismay, someone forgot to put the beverages in the refrigerator. Now you are stuck. You do not want to drink a beverage such as water, ice tea or a carbonated beverage that is at room temperature. You want to drink it, but it is too warm. You would prefer a temperature of 42F. What is the fastest way to cool down this beverage so you can drink it as soon as possible?
There are many options to cool down your beverage. Some of these are the following:
- Stick it in the refrigerator – this is great if you have the time.
- Stick it in the freezer – Watch out for freezing
- Run cold water over it –Hope you have plenty of cold water
- Stick it in an ice bath –
- Stick it in a crushed ice bath (In the winter you could also stick it into a snow bank).
- Stick it in a water and ice bath
- Rotate it in a water and ice bath
- Put ice cubes directly in it.
Experiment Design
In order to test the above options over a wide range of containers and bottles, the following items were used in the experiment:
- A digital thermometer
- A one half liter plastic water bottle (16.9 oz.)
- 1 glass ice tea bottle (16 oz.)
- A 12-ounce non-carbonated beverage can. Note – a carbonated beverage would have worked have been used, except I put a small hole in the top of the can for the thermometer and the carbonated beverage would have fizzled out of the can.
The goal of each test is to reduce the temperature from 70 F to 42F.
The following is a tabulation of results
The first value is for the 16.9 ounce plastic bottled followed by the 16 ounce glass beverage and 12 ounce aluminum can. All times are in minutes.
- Refrigerator – 463, 457, 305
- Freezer – 62, 51, 22
- Cold Water running over can – Neither container met goal of 42F
- Ice Bath – packed around beverage – 51, 55, 12
- Crushed Ice – packed around beverage – 20, 18, 8
- Ice and Water Bath – – 13, 15, 6
- Rotated can or bottle in Ice and water bath in insulated bin – 6.5, 6, 3.5
- Rotated can or bottle in salt & Ice and water bath in insulated bin – 6.5, 6, 3.5
Comments
- Refrigerator – Great for overnight or all day cooling
- Freezer – Possible danger of breakage if left unattended
- Cold Water running over can – Big waste of water, tap water is at 59F
- Ice Bath – packed around beverage – Time included partial melting of ice cubes as it cooled down the beverage
- Crushed Ice – packed around beverage – Times do not include crushing ice
- Ice and Water Bath – Great for multiple bottles
- Rotated can or bottle in Ice and water bath in insulated bin – Fastest undiluted method
- Rotated can or bottle in salt & Ice and water bath in insulated bin – Although the salt lowers the bath temperature to 28F, it didn’t have an appreciable effect on the time to cool it to 42F. This is useful if you wanted to reduce the temperature of the beverage below 40F
Conclusions
The refrigerator was the slowest because it had the lowest differential of final temperature. The freezer works faster if one remembers to remove it prior to freezing. Crushing the ice increase the surface contact with the beverage and thus has more conductive heat transfer. Adding water to the ice removes the air space which is a very poor thermal conductor. Rotating the beverage container allowed mixing of the fluid inside the can, which accelerated the heat transfer. Adding salt to the fastest time didn’t reduce the time, but did allow for a colder beverage below 42F.