A block of ice rests on a counter next to a plastic tupperware mold

Making Ice Blocks


Update for June 2020:

It’s hard to believe, but summer is here! And, hurricane season is almost here again in Florida!

That means it’s time to think about preparations and plans again. This season will be especially unique because we’ll have hurricane season, plus Covid-19. I’ll be making these blocks of ice to keep in my freezer in case we lose power, last-minute camping/trips, barbeques and more!

This winter I played with a few more experiments with making block ice, including how to make clear blocks of ice in my own freezer! It was fun and I had some cool results. I’m going to edit this post to include that new information. For anyone who stumbles upon this article, I hope you enjoy it!

Thanks so much to everyone who reaches out and tells me how this article has helped them. Y’all take care, stay safe and have fun! 

Block ice has been on my mind a lot lately because one of Florida’s first (major) named storms of the season– Hurricane Dorian— looks like it will probably hit Florida as a strong, major hurricane.

As I type this the National Hurricane Center is predicting that Dorian will probably be at least a category 2 or category 3 hurricane when it hits Florida’s east coast.

As we prepare for hurricane Dorian we’ll definitely be making ice blocks to keep our food safe in our freezer!

I always make block ice to keep in my freezer during hurricane season! It keeps food cold and safe when the electric goes out, and it’s always nice to have good ready ice in the freezer for camping and fishing! Plus it’s way cheaper than buying Reddy ice or trying to find block ice near me!

Block ice is useful in many situations because it lasts much longer than smaller ice cubes.

  • Hurricane Prep
  • Camping
  • Boating
  • Fishing
  • Beach
  • Road trips
  • Barbecues
  • Parties
  • More

In my many years of boating, adventuring and camping off-grid I’ve often wished I had ice blocks in my cooler. Unfortunately, finding block ice near me is hard, and it’s getting harder every year.

It used to be easy to grab a big block of ice at most grocery stores, but most stores stopped selling it. Today most people buy block from an specialized vendor or make it themselves.

Luckily it’s not hard to make ice blocks in your freezer. Almost anyone can do it with basic equipment and items found in most kitchens.

Making block ice isn’t rocket science, but it’s not as easy or straight-forward as it sounds. I’ve learned tips and tricks to avoid broken ice molds, ice-water spills and damaged freezers.

A measuring tape is used to measure a block ice mold
A systematic, experimental approach is best when making block ice

Do you need block ice?

First things first: is block ice the best solution for your needs? To answer that, consider these questions:

  • How long do you need the ice to last?
  • Do you need fast cooling?
  • Will you have access to a freezer?
  • Will you be able to buy more ice?
  • Do you have freezer space to make block ice?
  • Is there enough cooler space for block ice and your food?
  • Do you have the proper equipment to make a mold?
  • Is there enough time to make block ice?

The biggest advantage of block ice is that it lasts much longer before melting. This can be a lifesaver when planning a long trip without refrigeration, and it’s why most people are interested in block ice.

A close-up view of home-made block ice
Air bubbles and gaps can be avoided by adding small amounts of water at a time, and allowing them to freeze before adding more

Block ice is great because it takes much longer to melt. If you need ice to last a long time, and aren’t able to replenish your ice while out in the wilderness, or offshore in the ocean, block ice might be a great choice.

When block ice is the wrong choice

Block ice is a wonderful tool and it’s great for certain situations. But, like any other tool, it’s not the best choice for every situation.

Block ice isn’t any colder, or more powerful than other shapes of ice. In fact, it won’t get your stuff as cold as smaller chunks of ice, and it will probably take longer to get it cold.

If you’re looking for fast cooling, then block ice might not be the best choice. Smaller shaped chunks of ice provide a greater amount of ice surface area. That allows faster heat-exchange, and much faster cooling. But, smaller pieces of ice melt faster.

If you go with block ice, it’s important to pack your cooler correctly.

Not the best shape

A solid block of ice created in a freezer
Properly made, home-made block ice is a great and practical solution

Cooler packing is an essential art and science. A well-packed cooler should:

  • Minimize dead-air space
  • Maximize ice contact with items
  • Keep food from being contaminated by melt-water
  • Allow items to be easily accessible to minimize cooler open-time

Ideally food in a cooler should be totally surrounded and packed in ice.

Small cubes can be great for this because they can fill into small gaps. Block can’t be snuggled into small spaces.

To solve this problem some people use molds of different shapes and sizes to fill spaces more efficiently. You can also use a mixture of block ice and smaller ice cubes.

Chipping block ice

Commercial fishermen often buy ice in giant blocks. They keep it inside a walk-in freezer, and go inside the freezer to chip or crush the ice into small pieces, so it can completely surround fish without damage. The problem with this on a small-scale level is that you can’t chip ice inside a walk-in-freezer. For you, the block ice would be exposed to the warm outside air, so any time spent chipping or crushing will rapidly melt your ice. It is also very time and labor intensive to chip blocked ice. I don’t think it’s very practical outside of a commercial setting.

Block ice takes a long time to make. You really need to plan ahead, and know your space constraints. You need to find a balance: make your block as big as possible. But, not too big, because you still need to leave room for food. That is, unless you have a dedicated freezer for making ice at home.

Block ice: Use it or lose it

Your block of ice will start melting as soon as you take it out of the freezer. You’ll either need to start use it immediately or use a freezer to store the ice until you need it.

Don’t flood your freezer!

Storing block ice in a freezer can be a great idea, but be careful. Block ice contains a surprising amount of water, so have a plan in place in case it melts unexpectedly. This could happen for any number of reasons:

  • Lose power
  • Freezer door left open
  • Broken freezer

Freezers may or may not be designed to handle large amounts of water from melting ice. It’s best to plan ahead so you don’t have an unexpected meltdown!

I store my store blocks of ice inside leak and water-proof containers to prevent accidental floods.

Block Ice Alternatives

Ice Cubes

Pro’s: Faster cooling. Easier to find. Easier to manage. Fills spaces better.

Con’s: Melts faster.

Dry Ice

Pro’s: Doesn’t leave water melt. Lasts longer. Keeps food frozen, not just cold.

Con’s: Dangerous. Hard to find. Expensive. Might damage food and cooler.

Why make block ice?

There are many good reasons why people might want to make block ice:

  • Camping
  • Fishing
  • Road trips
  • Serving food
  • Food preservation
  • Hurricane and Emergency preparation

Block ice can be a great emergency backup for emergency, storm and hurricane season. In a worst case scenario, if electricity is out for days, it might give you enough time to eat your food, or find a solution before food goes bad

For this article I’ll focus on people who need block ice for boating, off-grid camping, emergency prep, cooler and food storage.

Experts in the outdoors community love block ice. When you’re away from electricity and civilization for days on end it can make food-logistics much easier to plan.

Sailing and boating communities love block ice too. They often use it instead of ready or cube ice because it lasts so much longer before melting.

Before boat refrigeration systems became more common it was the only way to keep food from spoiling on long boat trips. In fact, before electricity and modern refrigerators, both boats and houses had “ice boxes” to store ice blocks, instead of refrigerators and coolers.

Today, block ice is less common. Electric freezers, refrigerators and coolers have become commonplace.

Advances in solar panel and battery technology have also helped make portable refrigerator and freezer technology more accessible for ordinary consumers. But, all of these systems are still very expensive.

For most people who only camp, boat or go off-grid for a few days per year, block ice is usually the best choice by far. Thoughtful use of block ice might be a much more affordable and logical solution than spending thousands of dollars on a complicated and expensive electrical setup.

While writing this article I came across a few unexpected and hilarious uses for block ice as well. I wouldn’t necessarily recommend these uses, but they’re funny to imagine.

Some people said they put the ice blocks in their pool for a party.


Why would anyone do that? The water was too hot and they wanted to cool it down for their guests. Actually, a few people asked about this. Some of the questions sounded like they’d been written mid-party and after quite a few beers.

Some people tried it. This person said he bought a literal truck load of ice and dumped it into a pool but it didn’t even make a difference.

I’ve seen many DIY air conditioner contraptions that used block ice, a cooler and a fan.

How Block Ice Works: Surface Area

A solid block of ice created in a freezer
Properly made, home-made block ice is a great and practical solution

It’s easy to think of ice as being cold, and sharing its cold temperature. And it does, sort of.

But the real effect at work is not really ice sharing its cold, but rather absorbing heat from its environment.

Ice absorbs heat through its surface area. As it warms, the outer surface gets warmer and melts away. A new, fresh, cold layer of ice is exposed, which absorbs more heat. That cycle repeats until the ice is fully melted and none remains.

More surface area equals faster cooling

Side note: This is why some restaurants serve shaved ice, or round cubes with a hole in the middle. Both of these shapes provide a lot of surface area, and faster cooling than ice cubes.

Surface area is great for fast cooling. But, the ice melts quickly, and it won’t last very long. That might be bad if you’re on a multi-day trip and need ice to keep your food from spoiling.

Block ice has less surface area relative to its volume, so it melts slower and lasts longer.

Good idea even when you have a freezer

People who live in Florida and other tropical areas know that electricity can go out frequently and without notice.

I’ve lived in many places around the country and have never had such frequent power outages as my time here in Florida.

If you keep your freezer well-stocked, it might be a good idea to use block ice an emergency insurance policy. In an emergency it might help save a freezer full of food from going bad. But, be careful of accidental melting, so you don’t ruin your freezer!

Should you drain the ice water?

There’s a raging debate about this. Some people say that water in the bottom of a cooler makes remaining ice melt faster. Some people say that watery ice-melt helps keep the cooler colder for longer.

For all of the raging debate online, I haven’t seen much discussion of one critical consideration: Food contamination.

Food safety and preservation should be priority number one, and that means avoiding contamination. If your food packaging isn’t properly sealed, then make sure that ice-melt water doesn’t leak into food packaging to contaminate other food.

It can be helpful to use racks, tupperware and other tools to keep food away from sloshing ice melt-water.

Getting frozen ice out of the container

An overhead view of a plastic tupperware container, used to make block ice
Block ice is formed in a freezer-safe tupperware container

I expected this to be a difficult problem, but it was surprisingly easy.

To remove an ice block from its mold you only need a thin layer of ice to melt around the perimeter of the block. Then ,it slides out easily. Just remove the mold from the freezer and let it sit for a few minutes. The outside of the mold will warm up and melt enough ice for the block to be removed.

It probably won’t be necessary, but you can gently warm the outside walls of the mold and the block should slide out easily.

Good for Long trips

Block ice shows its value when on a long trip and there is no chance to make or buy more ice. Even if more block ice is not available, it may be possible to add more ice to a cooler in the form of ready-ice cubes or other widely available ice. Obviously this isn’t a possibility on long camping trips away from civilization, but for road-trippers or boaters who have access to a marina it may be a good way to extend the block ice and food.

How long will block ice last?

Under the right conditions, and when treated correctly, block ice can last for a very long time. The exact lifespan will depend on many things, so no accurate prediction can be made for how long it will last.

  • Time cooler is open
  • Air volume of cooler
  • How densely packed the cooler is
  • Temperature of items when placed in cooler
  • Temperature of freezer when ice is made
  • Outside temperature
  • Thermal efficiency of cooler
  • Shady or sunny conditions
  • Air ventilation around cooler

Tips for making block ice

Making block ice can take a long time.

The biggest tip is that you should start the process before you need it.

The time leading up to a big camping trip or outdoors adventure is often hectic and busy. Planning ahead and doing things in an orderly and systematic way can help reduce chaos and stress.

It might take one day, or even a few days, depending on your situation and several factors:

  • Amount of ice you need to make
  • Container/Mold
  • Freezer Temperature
  • Freezer space

If you need many blocks of ice and are short on freezer space or molds you may need to leave even more time.

Bring Your Own Ice

In a crunch you could ask friends and family members to help you by making blocks in their freezers. For example, on a group camping trip, if everyone brings a block of ice it can save a lot of time and energy instead of putting the burden all on one person.

Steps and Tips for Making Block Ice

Things you’ll need:

  • Freezer space (make sure the mold fits your freezer space)
  • A clean bottle or container that’s easy to pour water from
  • A suitable mold for making block ice (make sure it fits your cooler and freezer space) (test-pack cooler)
  • If you have lots of time, start with these two steps. If you’re short on time you can skip them.
    • Chill your mold by putting it in the freezer.
    • Pre-chill your bottle of water in the freezer or refrigerator

Thick plastic can act as a heat insulator, which will slow the freezing process. Make sure you’re starting out with cold ingredients, including a cold mold. If you’re short on time you can skip this step.

Next, find a bottle or container of water that you’ll use to refill your mold. This should be easy to pour inside your freezer without spilling. I used my nalgene bottle and really liked it because it has measurements built in.

We’re going to add water to our mold without moving it from the freezer. We do this to avoid carrying a sloshing, freezing mold of water around the kitchen.

Fill the bottle with cold tap water, and then put it in the fridge. You’ll use this later on to add water to your mold.

Cold water added from a water container allows block ice to freeze faster
Cold water added from a water container allows block ice to freeze faster

Next, put the mold in the freezer.

Ideally the mold should stay in this spot until it’s frozen solid.

It’s important to leave the mold in place and avoid moving it because it’s very easy to accidentally spill sloshing water while carrying it in a big mold. Make sure to arrange your freezer with this in mind— if you need something from the back, take it out before you start your block-ice-making adventure so you don’t have to move it later.

If you do take the mold out for some reason— maybe to look at it, like I did—be careful!

The top surface can seem solidly frozen but the water beneath is still liquid. It can be deceiving and lead to a tidal wave of sloshing cold water.

Pour some water into the mold. The exact amount of water will depend on your situation, including the size of your mold. The important thing here is to make sure you don’t add too much water. Only pour enough to lay a solid layer of starter-ice in the mold.

The reason for pouring a small layer of water a time is to avoid having a top layer of ice skin over and leave the water beneath unfrozen. A top layer of ice insulates the water beneath it and will take longer for the other water to freeze.

This method will also help avoid air bubbles that happen when a top layer freezes but there’s water and air beneath it. We want to avoid air bubbles in our block ice because they take up precious volume without any cooling benefit and can weaken the strength of the block.

After you pour a starter-layer in the ice mold shut the freezer and let it start to freeze. Make a note of your start time and start a timer to remind you to come back and add more water.

The exact duration of this waiting time will depend on the size of your mold, the temperature of your freezer, the amount of water you used and other factors. I waited two hours between refill session and it was fine for me. More time will probably be better in this process.

When your timer goes off it’s time to add more water. Take the cold bottle of water from your fridge. Leave the ice mold in place and add more water to the block.

Make a note of the time, set another timer and repeat. If you noticed that the ice needed more time you can increase the time interval of your next refill session.

Keep repeating the process until your block of ice is made to the desired size.

If you don’t have enough time you may be able to shave some time off the process by using ice cubes. To do this, place ice cubes in your mold and fill the surrounding area with water. Because you’re starting from a frozen base it should freeze much faster than using water alone.

Avoiding contaminated food

Make sure that any food that makes contact with water is completely sealed and water-tight. If water gets inside meat or other food it can contaminate all of the water and possibly cause illness.

Wire racks and creative use of stacking containers can keep food out of slushy ice water.

On the other hand, keep in mind that maintaining direct contact with ice is the most reliable way to keep food safely chilled, so it’s a fine balance between the two: submerged in ice water is better for cooling, but also carries an increased risk of contamination because water is an expert at finding its way into any container.

Containers for making block ice

A sturdy plastic tupperware container is used to make home-made block ice in a freezer
I made block ice at home using a sturdy plastic tupperware container

I’ve spent a lot of time looking for the perfect mold to make block ice.

Above all, a mold should be:

  • Freezer safe
  • Allow room for ice expansion
  • Material won’t be damaged by expanding ice
  • Don’t use anything that is glass, will shatter or break
  • Material is not too insulating

If you follow the method I describe below you will be adding water to your mold very slowly, a little bit at a time. This will reduce the chances of your mold container breaking, but it’s always a possibility.

Before beginning, ask yourself: if you open your freezer and see a giant crack in your mold, would you be upset? If the answer is yes, don’t use it.

The perfect storm: the frozen flood

If you add water all at once your container it might form a skim of ice along the top surface. The rest of the water will still be liquid.

If that top sheet of ice cracks your mold, like a rigid plastic that doesn’t allow room for expansion, the liquid in the mold might escape all over your freezer, creating a big mess and possibly damaging your freezer, if it can’t handle the water. Be careful!

The size of your mold should be as big as you want the ice block to be, but not too big.

In general bigger is better because the ice block will last longer. But, don’t go crazy here. If you make it too big it’ll be harder to deal with and it might prevent a good cooler packing arrangement.

If possible, I always recommend a cooler test-pack using your ice block mold container so you can see how everything fits together.

  • Determine what size you need: As big as possible, but not too big.
  • Check if it will fit in your freezer and cooler.
  • Ultimately the perfect mold will depend on several factors:
  • Right size for cooler
  • Right size for freezer
  • Right material: Flexible and not an insulator
  • Allow stacking in freezer while freezing
  • Easy to handle
  • Good ice block size

Ziplock bags to make block ice

I’m sad to say that I can’t recommend this method. Why am I sad about it? Because if it worked it would be so easy and nice.

Zip lock bags have a lot going for them:

  • They’re supposed to be water proof
  • They’re easy to find in almost any store
  • They come in various sizes so they can be arranged nicely in a cooler

I’ve tried to make this work many times and have never had good results. Every single time I’ve tried this it’s leaked. I’ve even tried putting crushed ice in ziplock bags so it lasts longer. That leaked too.

I feel perplex about this this because if you google “block ice” you’ll see so many people on the internet recommend this solution. I think people just recommend it and repeat the idea without ever having tried it.

I’ve also tried to put food inside the zip locks to keep food dry. Again, every time I come back I find that ice-melt water has made its way inside the ziplock bag.

So, as much as I wish this worked, I don’t recommend trying to use zip-lock bags to make block ice.

I’d love to hear tips from folks who have used this method successfully— maybe there is a secret or method I haven’t thought of.

Wine bags

I love this idea. I’ve spent a lot of time looking for materials that would be well-suited for making ice and never thought of this until I saw it mentioned in an outdoors forum.

I haven’t tried this, but am excited to. I’d love to hear feedback from anyone who’s tried it.

My only concern with this method are the durability of the bags and possible ruptures at inconvenient times.

Water and ice are heavy, and it takes a strong material and strong seams to stand up to the weight. Plus, ice can freeze into sharp edges. I wonder how the bags would hold up over time.

I also wonder about the dispenser bits— I wonder if expanding ice could cause cracking during the freeze-up period.

Molds to make block ice

A flimsy cardboard block ice mold burst as the water expanded.
Flimsy molds like cardboard are not good choices for re-usable block ice molds

Some people say they’ve had great luck using cardboard boxes as their form to make block ice.

I decided to give it a try using a cardboard (almond) box.

Juice-box advocates especially love the clean square and rectangular lines that the boxes yield, Clean 90-degree lines can allow for efficient packing in a cooler and help reduce dead air space.

Juice-boxers seem to especially love boxes with a screw lid. I’m not totally clear on this, but I think these people may leave the ice inside the sealed juice box after freezing. suppose the

Many other people use milk jugs, but most agree they’re not ideal because they can leave irregular shapes in a cooler that are hard to fill efficiently.

Juice box method: remove ice from the box, or leave it in?

I’m fully on board with the idea of using rectangular juice box as a mold for block ice. But, I’m not sure about the best method.

I wonder about whether it’d be best to leave it inside the box or remove it.

On one hand, having cold ice-melt water contained within a sealed box would be nice, and might keep the cold water colder for longer. It would also provide good, clean, usable water if the box were sufficiently clean before use.

On the other hand, cardboard can be an effective heat insulator, and I wonder if it would negatively affect the heat-exchange of the ice and cooler contents.

While making block ice in a cardboard almond milk box I noticed that the cardboard appeared to act as a good insulator. Even while adding small layers of water at a time I noticed that it froze significantly slower than I expected. I noticed that the outer perimeter of water froze quickly, but not all the way through. There was liquid, unfrozen water on the inside of the box.

I also noticed that the bottom of the box was not frozen. This was surprising because cold air and water sink below warmer sections. To fix this problem I used wooden clothes pins to elevate the box

When I try the juice box method in the future I will probably cut one side of the rectangle and use it as a mold lying vertically on its back to form the ice, and then remove before use in the cooler

What is Dry Ice?

Dry ice is a powerful tool. When dry ice is used correctly it can deliver amazing results and dramatically extend the cooling life of ice. But, when used improperly, dry ice is dangerous. Serious safety precautions must be taken.

When dry ice is used incorrectly it can cause serious problems including property damage, injury, or worse.

Users must be careful with dry ice for several reasons.

It can cause cause severe injuries.

Dry ice is so cold that when it makes contact with skin or sensitive tissue it can leave serious burns.

Dry ice produces C02 gas, which can be very dangerous.

When dry ice “melts” it turns from a solid into a gas— carbon dioxide (C02). This is actually not melting, but a process called sublimation, which is when a solid turns into a gas.

The production of C02 is a problem for two major reasons:

C02 displaces oxygen, so it is a suffocation hazard.

For example, imagine a car with the windows up and no ventilation. Now imagine there’s a cooler filled with dry ice inside the car. As the dry ice “melts” it releases C02. The C02 escapes from the cooler and displaces oxygen in the car. It could make you and/or other occupants lose consciousness, or worse. This is not a hypothetical scenario— there are at least several documented instances of this happening.



Dry ice should never be put into an air-tight container, there must always be a way for the C02 gas to escape into a well-ventilated area.

Some coolers use a gasket and latches. These can be great features, but they can create an air-tight seal that will trap C02 gas inside. A sealed container will build pressure until it ruptures the container, possibly causing an explosion, injury or damage.

Carbon dioxide gas displaces oxygen which can create a serious suffocation hazard. Do not store dry ice in an enclosed space and make sure that there is enough ventilation to provide safe levels of oxygen.

Don’t let children or animals use or be around dry ice.

It can damage your food by causing “freeze burn”.

If dry ice is too close, or touching food it can freeze it. That’s great if your goal is to freeze food, but it can cause freezer-burn and damage food that’s not meant to be frozen.

Coolers may or may not be compatible with dry ice. If it comes into contact with plastic it can damage the plastic.

Other containers to use a molds

Gatorade and thick-plastic bottles are great to use as ice molds. They are sturdy, flexible, durable, and are a great way to reuse plastic before recycling. The thick plastic is nice because it is very unlikely to break, and the strong, reliable screw-top won’t leak.

Other plastic containers can be used as well. Again, it’s a great opportunity reuse plastic before recycling. Yogurt containers are great, milk jugs, and basically any other container.

With thinner and more brittle plastic great care should be taken to avoid shattering the container. Again, with these, try to add smaller batches of water to freeze over time instead of filling it to the brim.

Smaller containers can be very useful for making an in-between compromise between a hulking block of ice and small ice cubes. Anything larger than an ice cube will be an improvement, and irregular shapes can be useful to fill dead air space in a cooler.

Be careful and prepare for unexpected cracks and leaks. If you do this enough eventually you’ll have a leak. Making block ice isn’t worth a ruined, flooded freezer isn’t worth it.

Many people talk about using non-stick baking dishes. With these it’s also a good idea to add water a little bit at a time instead of all-at-once. Covering the container with a sturdy container is useful because you can put food back on top of it and use it like a shelf, instead of losing all of the freezer space. If you’re making a bunch of blocks you can even stack them, although doing so may insulate the blocks and take longer to freeze. After you take the blocks out of your form you can put them into plastic bags to store them. It’s a good idea to store them inside a waterproof container after making your blocks to prevent an accidentally flooded freezer.

Strategies to make block ice last longer

Even the best, most expensive cooler will be a dud if not used correctly.

These steps are important with any cooler and any type of ice, including block ice.

Prepare the cooler first: This basic principal applies to any cooler and any form of ice. Pre-cooling items before going in the cooler will make your ice last much longer.

Divide and conquer

Consider using separate coolers and giving each one a specific job. One for drinks, etc., and one for food storage.

Food probably only needs to be accessed when cooking. People are in and out of a drink cooler constantly— every trip introduces heat and lets cold air escape.

Keep cooler

  • Closed
  • In the darkest, coolest place possible
  • Off hot ground
  • Cool: Possibly under a wet towel

Use stuff quickly and put it back in the cooler as soon as possible.

When outside of the cooler items will absorb heat. When they’re put back inside that heat will leech out into the cooler and warm everything up. It’ll make your ice work harder and it will melt faster.

Put food back inside the cooler as quick as possible, but keep the cooler closed as much as possible and minimize the number of times it’s opened. Every trip inside the cooler releases cold air and introduces hot air, which the ice will have to work to cool.

Try to package things individually before your trip. This will serve several purposes. You’ll minimize time spend looking for stuff inside the cooler, which keeps cold air from escaping. Plus you won’t put warm items back into the cooler after they’ve been outside.

Some things, especially condiments, are available in single-serve packets that don’t require refrigeration.

Everything that goes inside the cooler should be as cold as possible. Freeze or cool as much stuff as possible before leaving home, maybe even if it only requires refrigeration.

Don’t put hot food, like leftovers, back into a cooler. Let it cool down as much as possible first. Make sure to know and follow to safe food-handling practices.

Keep things in a sealed container whenever possible. But, make sure that things stay adequately cold. Dead-air space can insulate food and prevent cold air from cooling the food.

Even if you upgrade your system to a fridge/freezer, all of these things will help increase the efficiency of your system. Fridges and freezers might not require blocks of ice, but they require electricity, which might be coming from a solar panel or battery bank. Efficiency is important even with electric cooling.

  • Precook meals and freeze them before you go
  • You can cook frozen steaks from frozen. May be better than thawed.
  • Stack and arrange food in order of need: “combat loading” to reduce amount of time the cooler is open

Nalgene frozen busted warranty

Cold water added from a water container allows block ice to freeze faster
Cold water added from a water container allows block ice to freeze faster

While doing my block ice experiment I used my Nalgene bottle. I wanted to say a few words about this.

First, I love Nalgene for several reasons.

First, reusable bottles are a sign of good breeding. Like saying please and thank-you, and not belching at the dinner table, using a reusable water bottle says something about a person— just like disposable plastic bottles do. I won’t go off on a rant here about exactly what the messages say.

I think they make the best reusable water bottle on the market. Some people may quibble with this. I’l admit, I haven’t tried that many long-term because I’ve used Nalgene bottles for many years, but I keep a sharp eye out for different options in case anything better is available. In stores I check selections pretty frequently, but I have never seen anything that makes me want to switch.

These bottles stand up to serious abuse. I’ve dropped them from crazy heights, frozen them them countless times and generally treated them with total disregard. They just work. They don’t leak and they don’t break.

The next best thing about Nalgene is that if they do ever break, they’re covered by an insanely generous guarantee policy. I love products like this.

I can’t even guess how many times I’ve frozen Nalgene bottles, and they’ve never broken. I don’t know why, but one time recently mine did.

I was sad because I really liked the bottle, but my sadness turned to joy when I googled to see if their guarantee policy was still in effect. It was. I submitted the online form, snapped a photo of the damaged bottle and sent it off into the internet. Less than a week, just like Christmas, the mailman delivered later a brand new replacement bottle.

Should you dump cold water?

First, cold, melted ice water still provides cooling capabilities. In fact, icy-cold ice water might cool stuff faster and more thoroughly than a solid block of ice.

If you need rapid cooling you can pour water in with the ice. It will melt the ice faster because the water is warmer than freezing point, but it will help cool your drinks faster.

Water is a better insulator than air, so if the ice water melts in the bottom don’t drain it, unless you need to keep it from ruining food.

Cold air sinks. Ideally you’d put your ice above your food.

Probably bad ideas: Salt ice and Pykrite

  • Salt ice
  • Pykrite saw dust

Other Ideas


Use meat thermometers or digital thermometers to monitor food temperatures.