If you've got your packed lunch all ready to go in your insulated ice bag and you've got a frozen ice pack ready to keep things cold all day how do you know where to put your ice pack in your lunch bag.
Should it go on the top, on the bottom or somewhere else altogether? Believe it or not where you put your ice pack in your lunch bag will effect how long it lasts and how well it keeps your food cold.
To make it last longer you should put your ice pack at the bottom of your lunch bag touching the items you want to keep coldest. Putting your ice pack in the middle or at the top will keep items more evenly chilled but the ice pack will likely melt faster.
If you have multiple ice packs you can spread them out through your lunch box to get more even cooling of your food or you can stack them next to each other in the middle or at the bottom of your lunch bag to make them last longer.
Does It Matter Where You Put Your Ice Pack In Your Lunch Bag
Where you put your ice pack in your lunch bag does matter and does effect how long it will stay cold and how cold it will keep items.
To Help The Ice Pack Stay Colder Longer
PLACE YOUR ICE PACK AT THE BOTTOM OF YOUR LUNCH BOX
Often you have a lunch bag where some things need to stay cool (eg. yogurt, water bottle or drinks, cheest etc) and other items that don't need to be as cool (eg. sandwiches).
In this case you want to focus the ice pack on keeping the most important items cool and not wasting it's cold on things that are ok to warm up.
You have to remember that insulated lunch bags only SLOW the warming up or items, they don't actively cool items.
If you want your ice pack to stay cold as long as possible you want to place it at the bottom of your lunch bag and you want to place the coldest items on top of your ice pack.
This works for a couple of reasons:
We all know that heat rises, but the opposite is also true. Cold air sinks down.
This means if you place your ice pack at the bottom of your lunch box it's going to be in the coldest position and melt the slowest.
Also having the ice pack in the bottom exposes it to less warm food and thus less of it's cold is being used up to keep everything cool.
This means some items in your lunch bag will warm up faster – specifically those at the top of your bag furthest away from the ice pack.
However, the ice pack and the other cold items down the bottom should stay warmer than if you had the ice pack at the top or in the middle of your lunch bag.
If You Want To Evenly Cool Everything In Your Lunch Bag
PLACE ICE PACK IN MIDDLE OR AT THE TOP OF YOUR LUNCH BOX
If you want to keep all the items in your lunch bag evenly cooled so everything stays cold then you'll want to place your ice pack near the center of you lunch box so everything is touching it, or close to touching it.
This will melt the ice pack quicker than putting it at the bottom but it means everything will stay equally cold.
Also putting your ice pack at the top of your lunch bag (but still inside the lunch bag) can help keep everything cold too. This is because cold air sinks so the cold air around the ice pack will sink down over your food keeping it as cold as possible.
Where To Place Ice Packs In Lunch Box If You Have Multiple Ice Packs
If you have multiple ice packs there are 2 main ways you can go about placing them in your lunch box.
Spread Them Out To Cool Things Evenly
If you want to keep all your food evenly cool then spreading out multiple lunch packs so all food items are touching at least one ice pack will keep everything the coldest.
Items you want to keep extra cold you can stack between two ice packs so they are cooled from two different directions.
Spreading your ice packs apart like this will make them melt and warm up faster though so they won't last as long. This is a consideration you need to take into account.
Stack Them Together To Last Longer
If you stack your ice packs together and touching then they will help to insulate each other and keep each other cold, this means they will last longer.
Generally when you do this you either want to place the ice packs stacked at the bottom of your lunch box or stack them together in the middle of your lunch box with the food surrounding it.
Extra Tip To Make Ice Packs Last Longer In Your Lunch Bag
A simple tip to help your ice pack last longer in your lunch bag is to wrap it in a tea towel before placing it in your lunch bag.
The tea towel will help insulated the ice pack from the heat meaning it will warm up slower.
However, this also means that less cold will be transferred into your food. So your ice pack will last longer but it won't keep your food AS COLD.
In some circumstances though it's better to have food that's not quite as cold but an ice pack that stays cold for longer.