Summer Blog – Things we’ve learned about keeping food and drinks cold with ice
What is the ideal food and beverage temperature?
- Fridges and coolers should keep food below 40 degrees Fahrenheit to control bacteria.
- The favorite temperature for drinks in the US is 38 degrees, and 35 degrees for those who like it really ice cold.
- Ice from your home freezer is usually about 3 degrees when you take it out.
- You should consider food damage irreversible any time your cooler gets above 40 degrees for more than 2 hours. The bacteria growth cannot be reversed by getting your cooler colder again.
The thing about store bought ice for your cooler
Store bought ice is frequently just 15 degrees Fahrenheit at time of purchase. It’s not as cold as your home ice because it has either been recently made and has not fully chilled, or the freezer is not capable of getting it colder with the constant opening and closing of the doors. Starting at this temperature is a distinct disadvantage in trying to keep your food and drinks cold.
This is the most important point in this blog. Let me say it again…store bought ice is about 12 degrees warmer than ice from your fridge.
Ice spends most of its time at 32 degrees Fahrenheit. Yes, it starts out colder (freezer temperature) but quickly climbs to 32 degrees. Ice then stays at 32 until it melts into water (phase change science).
So, there it is. You are using 32 degree ice to keep food below 40, and drinks down below 38. Do you see the inherent problem with this?
Compare this to cooling your car or your home. You need the air temp that comes out of the vents to be much colder than the target temperature in order to counter all the negative forces working against you. Your car AC vent should blow at 35 degrees to keep your car at 75 degrees.
Dry ice cools at -109.3 degrees Fahrenheit to keep food frozen. Of course, because it’s so cold, you can use a smaller amount, but the principal stands.
Is this why Cooler Shock ice packs work so well?
Yes. Cooler Shock ice packs come out of your home fridge at about 3 degrees, it then gradually climbs to 18 degrees, then stays there for hours. 18 degrees is more than cold enough to bring your food down below 40, and your drinks down below 38 degrees. It’s cold enough to do this while fighting all the negative forces, such as lid opening, outside temperature or starting out with warm stuff.
Why don’t other ice packs cool at 18 degrees? Because the chemistry costs money. See the thing is the very stuff that allows us to make it freeze at 18 degrees also harms the gelling agent. We need the gelling agent for the whole thing to work and not separate. The result is that we have to invest in the best gelling agent (polymer) that is not easily harmed by the other ingredients. Other ice packs don’t do it because it makes it harder to make money. We think it’s worth it.