Icebox Coolers & Eskys

Australian’s love the outdoors and picnics in the park or BYO concerts are a part of everyday life. Soft cooler bags that can be slung over the shoulder are reasonably suitable for a picnic but don’t allow for ice, which melts and therefore needs drainage holes.

Keeping drinks cold is always best achieved on ice, so using a solid esky designed to carry the load of ice, with a drainage bung in one end is far better than a cooler bag.

This style of esky is as Australian as it comes. Just about every family has one for picnics; every beer drinking Aussie fills theirs with crushed ice and beers to take to BYO gatherings; and fishermen use them to keep the seagulls and sun off their bait.

Whilst “Esky” is actually a brand name, it is widely used colloquially for any brand of lightweight, polypropylene 2-shell solid cooler. Brand name Esky’s are typically blue with a white lid but variations with different brands do occur.

Eskys are designed to provide basic insulation with minimal weight so that they are easily portable for their size. A cheaper model may be good enough for parties, picnics or shopping trips and in more demanding scenarios, such as camping, you might be able to compensate by packing more ice or refilling the esky more often however you are very limited if solely relying on keeping perishables fresh (ie. below 4 degrees) for days on end.

It is the quality of the insulation that ultimately sets an esky apart from an icebox. Eskys are typically constructed of two layers - a polypropylene outer shell, with a polyurethane inner layer. The amount and quality of polyurethane foam insulation varies. There are 3 parts to an esky that may or may not have foam insulation – the base, the sides, and the lid.

Whilst a bag of ice or two in an esky is sufficient to keep drinks icy cold at a party, the longevity of ice becomes more critical for longer periods particularly when you have no access to replenish the ice. If you’re looking to gain a longer cold period from your portable non-powered cooler, then it’s time to look at an icebox.

Upgrading from the lightweight esky-style of cooler to a heavier, better insulated icebox is a good starting point, but how you manage your cold stuff is critical to the longevity of keeping the ice from melting for as long as possible, so in this article we’ll look at all these factors in detail and give you some tried and true tips.

Firstly, high performance iceboxes differ in that they use high density refrigeration grade injected foam insulation in the walls and lids of the cooler. The shell construction however, can be either plastic (poly) or fibreglass. There is a vast difference in price, with the poly boxes being far cheaper than the fibreglass design but which actually performs better?

We’ve actually had both, so in preparing this article we’ve reviewed all the manufacturers’ claims, together with our own experiences and those of the many people who contribute to Forum discussions on the subject.

To begin, let’s lay out the facts on each type of icebox:

Plastic/Poly Iceboxes

The plastic used in iceboxes is either High Density Polyethylene, or Polypropylene, which is rotomolded to produce the hollow forms of the icebox with walls of uniform thickness and stress-free corners. High-density polyurethane foam is then injected inside the walls and lids. In terms of application to a low-temperature, food grade container subjected to wet conditions, there is little difference between the two polymers.

However, there are differences! And price will be your best indicator. One of the reasons for a wide variation in price between brands of plastic iceboxes is due to the use of recycled vs first-grade plastic polymers. Iceboxes made from recycled polypropylene or polyethylene are unable to hold dry ice, and are likely to crack or chip and could suffer UV breakdown over time. (Note if using dry ice, you should always put a thick amount of hessian or a piece of plywood under it. This protects the plastic from becoming brittle and cracking after a number of times carrying dry ice).

Typically, a polyethylene icebox will keep ice frozen for three to five days when kept in the shade.
Variances in reported ice-life is usually more to do with ice management than the brand of the box. (More about that at the end of this article).

Advantages of Plastic Iceboxes

Low Price Tag:- Polyethylene/Polypropylene iceboxes are typically cheaper to buy than fibreglass iceboxes. This is mostly due to construction methods but most are made overseas and imported into Australia. Remember, "Australian designed" and "Australian owned" doesn’t mean "Australian made".

Very Robust:- The rotomoulded construction of these eskies is such that they are far more resistant to knocks than fibreglass iceboxes meaning they are less likely to be damaged on long trips. In terms of cabinet construction, each brand is probably as good as the next, however there are some major differences between hinges, latches, bungs, and handles that will be covered later in this article.

Large Range of Sizes:- The construction methods of rotomolding plastic means manufacturers can produce an array of sizes relatively cheaply. They range from as small as 10L right up to commercial sizes of around 1100L.

Important Features

When looking to buy a plastic icebox, you'll quickly discover that there are many many brands on the market and it is difficult to know which one is better than the other. As I've already stated, when comparing apples to apples, there is very little difference between the brands but there are some design features and use of materials that do make a difference. Here are our suggestions for what you should be looking for when choosing a plastic icebox.

Size/Bulk:- plastic boxes are inherently bulky for their volume capacity so if it’s a dedicated drinks box you will need a rather large one. Don't be fooled by their physical size, check the actual capacity and remember the packing tips (below). It is better to aim to pack the whole amount cold before you leave rather than plan to add a few more cans every day.

Handles:- One thing you don’t want is flimsy, brittle handles – look for good quality, strong polypropylene handles. You’ll be dragging and moving the heavy icebox full of ice and drinks around to chase the shade so there is a lot of load here. Positioning and design is also important, more so with the larger capacity iceboxes. Anecdotal reports on broken handles from different brands would be worth considering, so this is one area where Forum comments are worth checking.

Bungs:- look for a bung that doesn’t protrude and won’t break if you bump it.

Latch:- a sensible latch that is easy to use but also adds downwards pressure to help close the seal is important. Personally, I like elastic latches as do most others it seems.

Seal:- getting a good seal is important, obviously, to keep hot air from making its way in to melt your ice. Here's a trick to help you check the seal in the shop: close the lid, latch it down. Put a business card (here's a good use for your ExplorOz Member Card) in between the foam seal on the lid and the foam seal on the box. Now gently pull the business card along the seal right around the box. It should have resistance against it at all times. If the business card slides freely with no resistance, the box is not sealing properly and you shouldn’t buy it.

Lid/Hinge:- polypropylene or metal hinges are less likely to break. Check to see if the lid will stay open without holding it up, or you’ll find it very annoying to pack and remove items, especially in larger models were you might need to dig down to find what you want.

Fibreglass Iceboxes

There are considerably less manufacturers of fibreglass iceboxes on the market as there is more demand for the cheaper plastic ones, however they are considered the better option if you can afford one.

Advantages of Fibreglass Iceboxes

• Better finish/appearance
• Doesn’t expand or shrink during temperature fluctuations
• Fibreglass (depending on its colour) reflects almost 95% of heat so will naturally have a better capability to hold ice longer (usually 1-2 days extra)
• Fibreglass can handle dry ice
• Fibreglass can be repaired to look as-new if damaged
• Fibreglass iceboxes have good external size to volume ratio due, ie. less bulky
• Lighter weight for volume, makes them easier to manage
• Major fibreglass icebox manufacturer is Australian owned company with Australian manufacturing plant.

As I've already stated, how you manage the products in your icebox is critical to the longevity of the ice. Regardless of whether you use a poly plastic or fibreglass icebox the basic principles are the same. Follow these steps to achieve the best results.

• The day before loading your icebox, pre-cool it by putting ice (or icebricks) into the icebox.
• If using crushed or block ice, drain the next day before packing.
• Chill (or freeze) items to pack before loading.
• Minimise time that lid is open during packing (organise items to pack before loading).
• Pack ice to a ratio of 1/3 ice to 2/3 product (drinks/food). Well cured ice is important. Block ice is best and best if you can get it from an ice factory and cut it to size to minimise air gaps in your icebox. If you can’t get block ice, freeze water in empty 2L plastic milk containers (only 1/2 fill to allow for expansion without warping shape).
• If using crushed ice, leave it to settle for an hour, then shake to allow ice to resettle into air gaps, then top up with more ice to reduce the amount of air space in the icebox.
• Always keep your icebox in the shadiest, coolest spot. Monitor it throughout the day and shift it to keep it in the shade. Covering the icebox will definitely help. A reflective windscreen shade works well.
• Minimise how many times a day the icebox is opened and for how long the lid is left open each time. Use by children should be monitored closely!
• Never refill with warm items. If you add more drinks/food always pre-chill these – if no powered fridge is available to help you, leave items out overnight wrapped in a wet tea-towel and load into the fridge before dawn. The coolest part of the day is often just before dawn.
• If you are using a mix of block ice and frozen water bottles, the bottles will help keep the water cold so it may be counterproductive to drain off the water. Test the water before deciding to drain it – if its cold, keep it. If its warmer than you’d like to drink your beer, then tip it!

Having owned and used both plastic and fibreglass models of iceboxes we’ve identified a number of commonly promoted pros/cons that seem to be urban myths as they don’t stand up in our experience to be indicative reasons to favour one over the other.
These myths are:

Plastic holds smells more than fibreglass:- False. In our experience, neither type of icebox is immune to withstanding some absorption of food smells. For both boxes, we have taken the trip as a drinks storage and overflow fridge for up to 3 weeks. Obviously, the ice melted well before 3 weeks so in both circumstances we simply drained out the water, let it dry naturally and then closed the lid to avoid damage until returning home. Both types of boxes in this situation need cleaning and airing to remove odours once we were home.

Ice lasts longer in fibreglass:- Debatable. It all depends on how you prepare and care for the ice. The facts are, ice lasts longer if you use block ice and you follow the steps listed above to keep it cold longer. We have actually kept ice frozen for longest when using a plastic icebox BUT only because when we tested the fibreglass box we didn't exercise as much caution because we assumed that ice would simply last longer BECAUSE it was in the fibreglass box. In fact, the best results will come when you use block ice slabs from the ice factory cut to size to line the base of the icebox. When we have prepared a plastic icebox in this way, compared to just using frozen water bottles in a fibreglass box, the results speak for themselves. But all things being equal, tests typically show fibreglass boxes do keep ice better. With that said however, we've achieved over 9 days of ice in summer temperatures for large 100L iceboxes of plastic construction and of fibreglass construction, with 15 days achieved when using block factory ice. So the answer is that ice lasts longest when conditions are optimal, regardless of cabinet materials.

You can’t sit on the lid of a fibreglass icebox:- False. Whilst we didn’t test this, the instruction sheet that comes with the Evakook fibreglass icebox states “Your Evakool Icebox is strong enough to be used as a seat”.

Plastic iceboxes are lightweight:- False! Due to their extra bulk to volume, a plastic icebox is much heavier than the fibreglass. I have no idea where this myth has come from. As a female, I was unable to single-highhandedly manage movement (drag to keep in shade) of an 80L plastic icebox fully loaded but could adequately manage to move a 110L fibreglass icebox.

At the end of the day, the right icebox for you is one that you can afford. Whichever one you opt for the way to keep your ice longer is to follow the steps given above to minimise the heating of your icebox contents.