The TRUTH About Draining Your Cooler - According to Science 

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A simplified view is to look at the thermal mass. Your constantly losing cold mass in one by draining cold water. Therefore, at any given time, that cooler has less thermal mass and less thermal inertia meaning it's easier to change the temp. Gets hotter faster.

It isn’t about ice retention. It’s all about keeping the temperature low.

Very simple. Mass retains temperature. The draining water removes mass AND cold. The absence of cold leaves what? Thanks for your time involved in this experiment...........Be well.

RTIC is absolutely right. Drain the water and replace with fresh ice at every opportunity. Also, a couple more points: 1) Endeavor to make the food and beverages as cold as possible BEFORE you put them in the cooler. If you put warm items into a cooler, a great deal of ice mass will be wasted just getting it to temp. If your food items can safely be frozen, freeze them before you put them in the cooler. 2) Put the food and beverages in FIRST, then put the ice on top of them. Ice on top will provide a thermal barrier from the warmer air above.

I'd like to see this same test except instead of checking the temperature of the air/water inside of the cooler, you pull out a can of soda when you check, and you measure the temperature of the soda inside the can. Because the whole point of the cooler is to get what ever is inside the can cold, the air temperature is an intermediate part of the process, the fluid inside the can is the final result.

I bet if you measure the temperature of the cans and not air temp the cans stay colder longer in the non drain. Ice melts, you get cold water insulating the cans. In the drained cooler the ice melts you get air around the cans. The goal should be to keep the product cold not to keep ice longer.

As a Ph.D. field geologist and former chemistry teacher, I think the key is all about retaining the lower temperature THERMAL MASS. Meaning, near-freezing ice-melt cold liquid water (remember both coolers started with identical amounts of ice from the same source = same temperature) has more thermal mass than the depleted ice which had the melt liquid removed. And since H2O has such a high heat capacity (meaning it takes a lot of heat energy to warm it up, first to melting and then to ever-warmer liquid), the greater water mass of the undrained cooler will "resist" heat incursion (outside heat, greater than inside, is continuously "creeping into both coolers since heat flows from more to less) longer than the smaller thermal mass of water in the drained cooler. Btw a good way to further extend the cooler's coolness is to wrap the cooler in a mylar space blanket to reduce the amount and rate of outside heat making its way into the cooler. Some exterior heat will "bounce" off the mylar and not burden (warm up) the ice. Many smaller factors are also at work here but are less influential. For example, warm air is sneaking into the drained cooler via its open plug. That cooler would warm up slower if it had been drained often but no fresh warm air allowed back in. Protecting/holding on to the cooler air in a sealed "drained cooler" would be cooler (win!) but still have faaaaar less thermal mass than the undrained ice bath cooler (thus the drained cooler will still warm up faster than the greater thermal mass ice bath.

Would've been great if you measured the temp of one of the drinks from each cooler at different stages. Because we don't use coolers to watch ice melt.

One potential flaw in your test is that you left the cap off the entire time on the drain. If you would have drained 4 times a day which would allows the cap to stay on most of the time and therefore not allowing the introduction of higher outside air temperature at all times would make a difference I would imagine. You should do the test again!! 😂😂

as a mechanical engineer with many year in industrial refrigeration I would note ge following 1 Define What Want I would recommend a target of a beverage at 45F or cooler 2 Measure Directly Make a soda filled can with a probe inside 3 Comps What you are looking to measure is How Long each method can maintain the target temp. Fundamentals there are 2 key components of heat (or cold) in water: Specific heat and Latent heat of fusion. Latent heat of fusion is much larger in general. In theory you would retain the water until the bath gets near the target temp, then dump all the water

I've done both for decades. My bottom line is drain for food and don't drain for drinks. The thermal mass of cold water is great for retaining steady temps, but the inner surface of the cooler is in 100 percent contact with 5 out of 6 sides of that thermal mass where drained ice has air between the nuggets. So that from my experience evens things out. Your results are on point. For drinks, that thermal mass can keep ALL the drinks in the cooler at the same cold temperature longer. But difference is often not worth the hassle that a big cooler full of heavy sloshing water can create. For food? Is there anything worse than a leaky zip lock bag of ham full of water? Yes! A leaky zip lock bag of cheese full of water. No thank you. This is why I drain food coolers. Measuring the air temperature at the top of the cooler is pretty much, but not totally worthless. That's not where the drinks or the food are. Hot air rises, cold air sinks. My best recommendation for any cooler is to keep them off the ground and out of the sun. I get insulated foam sheathing board at the local home center and cut out the foot print of the cooler to set them on, which helps quite a bit, but even setting the cooler on a couple of wood strips will go a long way. Setting a cooler on concrete, dirt, or sand is a bad idea if ice retention is the goal. This is only a big issue if you are going out for long periods. An extra bag or two of ice can sometimes be a better expense than a cooler that costs many times more, especially if you are only on a 3 day trip.

The ice retention test that started the drama 👉 ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-J0Nel351sbg.html NEW ice retention test with 38 coolers! 👉 ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-TiIP6JLu9Jc.html The cheap cooler I used for this test is actually pretty great! amzn.to/3RtU0AS (affiliate link, FYI)

The temp just under the lid is of little importance, what you need to know is if your food is being kept in the safe zone so that bacteria is not multiplying dangerously. As such the thermometers would have been better placed lower in the coolers, either at the bottom or attached to a can. To make it fair I’d have placed both probes in saucers of water at the bottom so that they were measuring the temp of the water retained in them.

This video was a lot cooler then I expected.

Your drinks will stay colder in ice water.

The melted ice has a much higher thermal mass than air so it is going to slow the rate of the temperature change. Often times it is best to drain the cooler because it makes it easier to carry and you are only using your cooler for a day or two.

I fill empty juice bottles with water and freeze them. I don’t know if it keeps things colder, but the ice seems to last longest that way and my stuff doesn’t get wet.

The most simple view: think of trying to boil water. The more water you have the longer it takes to boil. The more mass you have the longer and more energy it takes to change that temp

One possible issue with this experiment is the thermometer is located on the lid, not where the drinks are. The draining cooler has more air, thus more room for hot air to accumulate. I wonder if having the thermometer measure the temp of the beverages themselves would show different results? Regardless, thank you doing this important experiment, I have argued about this too many damm times!

Depends on the application. If you're using the cooler for drinks and sealed food products, don't drain it. If you want to avoid water intrusion into food items or want to have ice available for use in drinks and such, drain it. There's a reason why AC and heating units pull out the moisture in the air to effect temperature changes. Moisture, humidity retain thermal conditions.

Bottom line is I bet the Cokes in your ice bath/water cooler are a lot colder than the cans in the cooler with dry, cube ice. I would guess the water transmits temperature more efficiently to aluminum cans, or a gallon jug of milk, than air.

I think the most amazing thing is how great those Coleman coolers worked

Thank you for answering a trivial question I have had but never before disturbed enough to seek an answer.

Both. We put a foam sub-cooler with meat inside into our main unit .The smaller sub-cooler has 4" of foam by itself. Sub-cooler meat starts out frozen solid. We move what's needed for the next day to the undrained space outside the sub after putting it inside a ziploc so it is ready for the grill or stove. This approach approximates a freezer and refrigerator juxtaposition.

I misread the title and thought it said the truth about dating your cooler

Yeah I can really only imagine fringe cases where keeping the ice longer rather than being concerned with thermal mass is the priority. Cool video.

Your temperature differences are not insignificant! 5-10 degrees F is drastic in bacterial growth rates. Thanks for the GREAT experiment!

Not really, the ice will melt at 32F and water contacting the ice will also be 32F. The ice being less dense will begin floating on the water that is forming. The water will initially remain at 32F and as more water forms under the ice, the coldest water being denser than the warmest water on top will sink to the bottom, starting a natural circulation that will continue until the ice melts. What you are missing is the fact that the water remaining is cold, probably averaging about 33F. Why would you throw that water away? If you start with 10lbs of ice ultimately you will have 10lbs of water, but it will be only slightly above the 32F melting point. The temperature differential between say 33F water and an average of 80F outside air temperature is 47 degrees X 10lbs= 470 BTUs of cooling potential remaining in the water. This is the equivalent to melting another 3lbs of ice. How long that lasts would be determined by the thermal gain (insulation) of the cooler. PS: You should have been measuring the temperature of the Coke can nearest the center of the cooler, the air temp meant very little. Hope this makes sense, I'm really sleepy!

I think this matters more on the refill of ice into a cooler, if the water is significantly warm then drain it but if the water is still ice cold then just add ice because there wont be as big of a temperature swing compared to the air or the warm water

That's what i loved about the ROVR it stores the water in lower chamber away from ice keeping your dry chamber colder.

The only time that I would recommend letting the water drain is when meat from a wild game harvest is being stored in a cooler until it can be processed. I’ve been processing wild game meat for over 10 years, it makes a huge difference in the quality of meat if it’s been stored soaking in icy water, or packed in ice with less water retention.

I'm of the camp that replacing cold water with warm air causes the ice to melt faster, but I'm interested in seeing how this turns out.

Nice video. If you really want to see the benefit of keeping the water in the cooler, try removing some cold drinks and replacing them with uncooled drinks. As long as the water is significantly cooler than the drinks you are putting in, the drinks will cool faster when surrounded by water than when surrounded by air.

man i really enjoyed your video. thanks for putting your time and resources into making this video because for one really appreciate you.

Talk about missing the forest for the trees, who cares when there is no more ice or if there’s a little bit of ice left, not draining kept the inside at what ended up being a pretty significant difference at the end. And I’ll tell you in Phoenix it does matter, the drinks would be warm in a day or two if you let the water drain out. Also you didn’t even touch on the real reason why not to let the water out and even why it had less ice but remained colder and it had nothing to do with replacing air or insulating the ice. Water has an enormous potential for absorbing heat. Its one of the best heat sink materials because it absorbs so much. So for the same reason it melted the ice quicker is why it kept the contents cooler is because it sucked up all the potential energy. In Phoenix we add more ice after the original ice melts because we want as much water in a cooler as possible and melting ice just makes room for more.

This was an interesting experiment and I thank you for making the content. Having said that, I think it was a flawed experiment. I took Physics in High School back in 1972 when you could still receive a decent public school education in most cities. I also had some physics classes at the college level while serving my Industrial Maintenance apprenticeship, right after High School, again, back when education seems to have been done better, so I'm not an expert, but I was a good student that paid attention because he believed that there really was a "permanent record" and was therefore a geek. I remember learning, in the "thermodynamics" section of my courses, that when ice at 32 degrees turns into water at 32 degrees it will absorb about 80 calories of heat per gram from its surroundings to do so. It's called the latent heat of fusion and it simple means the extra calories given off to turn water to ice or absorbed to turn ice back into water. No temperature change takes place while this is happening. For the record, there is a similar thing going on when water turns to steam and is the reason steam burns you worse than boiling water. Sorry for the digression, but I did warn you that I was a geek. At any rate, that heat is absorbed from whatever is in contact with the ice. In your cooler that would be the cans of pop and the air. Every material has a differing ability to transfer and absorb and retain heat energy and that is called its "specific heat". The aluminum surrounding the pop is a very good conductor of heat (that's why they marketed, well before your time, the first aluminum beer cans as "quick chill cans") and soda is mostly water, which is also a good conductor when compared to the only other thing in the cooler, which is the air. The latent heat of fusion isn't the only thing that the ice has going for it. Even after the ice has melted the water, still at 32 degrees, has plenty of ability to continue to absorb heat until it reaches an equilibrium with its surroundings. The transfer slows as that equilibrium approaches, but it is still SOME transfer. When you let that water out it ceases to make contact with the cans of soda and and it can no longer suck the heat from the can and it is being replaced by warm air on top of that. And here is the flaw in your experiment. I don't know about you, but I couldn't care less about the temperature of the air inside my cooler, which is what you were measuring. I am rather more interested in the temperature of the stuff I've been trying to chill in the ice in the cooler and how long it stays at an acceptable temperature ( I like my beer at about 36 degrees, for instance) You should have been measuring the temperature of your sodas, not the air in the cooler. Since you were letting a great deal of the cooling potential out the drain hole, I'm certain that once all the ice was gone in both coolers you would have found the contents of the cans in the sealed drain cooler to be colder and would have remained so for much longer as the pops in the other cooler quickly warmed up. It took a certain amount of energy to make the ice and in one cooler you used all that energy to chill the contents and in the other you let a substantial amount of that energy cool the dirt outside the drain plug. Maybe you could get some additional content by restructuring your experiment to test the contents of a can of pop from each cooler every 8 -10 hours while there is still ice and then onward as they warm up. Again, thanks for the content because I'm too lazy to make any myself. LOL

I'll simplify: With the drain plug open you're replacing the cold ice water with warm outside air constantly. Ice water is obviously colder than outside warm/hot air. Also, heat rises, cold falls. So even the ice-cooled air inside the cooler will be "pouring" out the open drain plug and warm outside air will be rising in to replace it. So basically you should leave the water in unless you're concerned about something in the cooler getting wet. If you're going to drain it then you should only do it occasionally instead of leaving it uncapped constantly.

I'm going to make a hypothesis here before watching the video. If you're draining water that is only just above the point of thawing, what temperature air is replacing that volume? Warm air contains thermal energy that will be taken up by the ice and increase melting, whereas ice cold water contains little thermal energy. In the end, water that is a degree above freezing will still be colder than a fridge. Water also doesn't move around a lot when you're using the cooler, meaning that warmer air doesn't come in contact with the ice on a regular basis. Edit: ayyyy! Great video, man!

Just started watching this. I would think that leaving the drain valve open would allow cold air to leave and be replaced by warm air.

You should have put a temp sensor in a bottle of the liquid because the whole point of a cooler is to keep drinks cool the longest, not preserve ice. The sodas in the drained cooler would have been much warmer than the non-drained cooler. The reason is due to the mass of water vs. air.

What I’ve always done. Cooling bottled or canned drinks, leave water in. Cooling foods like sandwich meat, condiments, cheeses, meats. Then I drain to prevent water from entering the food packaging.

Depends on how often the cooler will be opened, as the water will help the cooler retain and recover after the lid is opened. I would run a test opening the cooler often vs seldom. And then compare the 2 coolers. The one with more air will not only let more thermal mass escape, but potentially the open plug at the bottom will also facilitate the loss of cold air each time it is opened. Each time it is opened, the ice has to melt a little (more) to return the air to equilibrium.

I try to use as much solid ice as possible, I’ll freeze some gallons and then use them for drinking. I also use a small liquid hand pump to remove water whenever I am about to add more ice. I use the pump because I don’t have to remove the cooler from my car to get the water to drain. HaborFreight or Amazon have the pump I use, it looks like a short bicycle pump , comes with hoses and is very inexpensive. Because I’m camping out of a Prius I don’t want water spilling or leaking onto the battery I make a “bathtub” out of a tarp, and tape it around the cooler with just the lid exposed. Which makes it hard to access the drain plug. I also get a sheet of rigid foam insulation and sandwich pieces between the cooler and tarp on five sides, with another piece the size of the lid just left laying on top with a towel or moving blanket covering it. My 90L igloo works great like this, it’s big enough to pack a lot of ice and keep the ratio of ice to items high. The added insulation seems to help a lot and the cooler stays put, so if it cools where it is sitting in the car you don’t disturb it and lose whatever slight advantage it gives. I’m packed up and heading to the mountains in NC for some backpacking and car camping. Sometimes I am just a short hike in from the car and I can return daily with a smaller cooler to retrieve my daily allotment of beer. Having a large well insulated cooler at the car means I don’t have to leave my spot for a long time. Less driving and more enjoying the outdoors Thanks for the video, well done!

The ultimate question would be: “how cold is the contents in a coke can at the end of each day?”, since keeping the contents of the cooler coldest the longest is the ultimate goal.

One of the biggest problems in this test. Is you did not have a third cooler. This cooler you drain the water but you reseal the plug after you drain it. So one test you have the water continuously draining. The second test you drain the water periodically and then reclose the drain. In the final test you leave it closed.

Interesting. So, draining the water helps to retain the ice itself, but keeping the water keeps your food/drinks colder longer. Thanks for the info.

What about an ice block?

Thank you for making this video

I can't believe none of them mentioned that the "already chilled water" has a "mass" that is already chilled and should therefore help to maintain the cooler temperature longer, because the greater the mass, the longer it will take for the temperature to change.

I'd like to see a similar test with 2 coolers in a car or back of a truck where the ice/ water is sloshed around. Moving water rapidly erodes ice.

Convective heat loss is greater through water than through air. Ergo, the opposite is true in the retention of cold because water is denser than air and retains cold longer than air. Trust me bro. I stayed at a Holiday Inn Express last night.

Water with ice in it will be 32 degrees. So the water in the ice chest will be 32 while the air above will measure a higher temperature due to heat rising. Theoretically if you fill the chest completely, no air should keep the chest colder for longer.

I look at it from this perspective: If water can get out, air can get in, and as the RTIC people said, air is the enemy.

Thanks. This question has bugged me for decades. Interesting to find out it didn't make much difference.

Growing up, ice was sold in a single solid block for a lower price than "party ice" like you used. Mom used to do as others have mentioned, and freeze her own blocks for our cooler. I would question the "is it better" solid block vs party ice :)

Duh Add salt for best performance.

good work

Thank you for this, love the science!

It's simple, if you let cold water drip out, that amount of "cold" is lost.

the reason why draining was resulting in higher temperature is because the open hole in the cooler is allowing some kind of air transfer from the wind blowing, cycling the air inside the cooler. if you had done this inside a place where there was no wind, such as inside a garage, you might have different results.

Ice with water only has the surface area of the top exposed, while the drained cooler has tons more surface area between the ice cubes.

Another thing to consider is that water in its liquid state has a very high specific heat capacity (in fact twice as much as it does when solid). Not only does this help cool the air within the vessel better, it also slows the process of melting ice, so the contents stay cooler longer too.

Very nice, concise, well explained, and thorough

Adding a +1 to the thermal mass comments. Something you'll learn very quickly when the power goes out, is that a fridge full of food will hold temperature much longer than one that's empty. I'd also be curious if just leaving the cap off is letting cold air out the bottom, as cold air sinks, so you're losing *both* of your thermal masses.

Middle of summer, Central Florida. Company BBQ lunch with a cooler packed with Ice / water and soda cans, stored and left outside, undrained.... Day and a half later, soda is still cool and refreshing. That's all the science I need on the subject.

Great test! You brushed on this at the end of your vid, but I’d say Arctic who said to drain water and add fresh ice if possible (but to leave water in if you couldn’t add ice) should have been called a DEFINITE “don’t drain” score, since under your conditions they clearly said not to drain. Of course it’s obvious if you can drain the melted water and replace the ice, that’s going to give the best result, and I think all the cooler companies would agree with that. Love how a simple real world test usually trumps craploads of theories. Great idea!!!

Great video. Anybody else wanted to immediately buy one of these coolers? Impressive!!

Amazing video. Surprised to see the channel doesn't have even 100k yet! Big channel quality content.

I never knew coolers were so complicated. Glad I didn't waste a lot of time overthinking it.

I figured out if I fill a freezer bag 1/4 the way full and let it freeze flat I end up with perfect ice blocks and there's never any mess. I lined the floor and walls with them and covered the food and put in a little refrigerator ice. I was glad that open containers didn't get wet. I've had good success and still using the same bags!

I am 48 years old live in southeast US and I have worked outdoors my entire life and I can promise you that if you will drain your ice chest daily but leave 2 or 3 in of water in the bottom when filling it with ice in the mornings you will have the best results.

What rtic said was exactly what i was going to say from my experience living in a van with a cooler. Drain and replace with ice if possible, keep the water if not. I like to put 8 or so cans at the bottom and put things that you want dry on top, as the ice melt the items will sit on the cans above the water and stay fairly dry. Also buy block ice when you can!

I always keep the melted ice water in my cooler because when you add drinks they cool down much faster because of the greater thermal transfer. Drinks in ice water have 100% thermal contact. Drinks in ice with no water have some contact with ice and some with air. Water is 25 X better than air at conducting heat. Plus you maintain a larger thermal mass.

Great attention to detail. Thanks

So, what I have done for more than 20 years is I will freeze 1 gallon jugs and will add ice on top of that. Works great for a long weekend. Any meat will stay frozen until ready to use in upper baskets. Rarely need to add ice. Rtic 65 is what I’m currently using.

We used to go on extended camping trips... the knd where each guy took a case of beer for each day we camped. Our best results were to never drain until new ice was added, always keep a few inches of water in the bottom to quickly chill added beer, and ultimately, cold water keeps beer colder than a few remaining ice cubes. Great test.

You can keep a cooler’s contents colder longer by putting a towel over the contents inside the cooler further insulating it

Mechanical engineer here. I'm making this comment before I watch. I say it depends on the volume of ice to be melted and the thermal insulation, but for the vast majority of scenarios I can conjure, leaving the water in ought to stabilize the temperature better than air would. Although air has greater thermal resistance, water has greater thermal capacity by volume by a large factor, so unless theres a thermal sink, the water will have the advantage. This is partially also why we use liquid cooling in PCs and such. The thermal capacity, meaning how much energy it costs to raise or lower the temperature, of water is high relative to basically everything else, so it is a great material for both heat transfer and heat retention.

It has been a long time since I've been to any event that had a cooler. So I'm most impressed by the fact the the ice lasted a week. I thought it would melt within a day. Very simple but well done test.

I did this same experiment, drain water over night: hot drinks Don’t drain over night: water in cooler but drinks still cold 🤷‍♂️

For any given cooler if your goal is to keep the contents as cold as possible for as long as possible three principles should be followed: 1. Pre chill the cooler 2. Pre chill the food, beverage, bait or whatever else you will be storing in the cooler. 3. Fill the cooler with the coldest ice you can get. Ice melts at 32°F, but the bag/block of ice that you place in the cooler have a temperature of 31° or -20° or any other temperature lower than 32°. The colder the ice starting out the longer it will take to melt. So not all bags of ice are equal.

So, when water touches ice, it melts the ice. And obviously, ice does not turn your water back into ice. So, what I've done, is buy a cheap cooling rack that fits in the bottom of my cooler. I use some bolts and washers as feet and place it into the bottom of my cooler making sure it sits about 1 - 2 inches above the bottom of the cooler. Then load the cooler as normal. This adds a day or two of ice to all of my coolers. I also tape the top inside of the lid with foil (reflective), but I don't know how much that helps. It's an easy weekend project. Cheers

I think it's pretty simple in practical application. I usually carry 2 coolers for long trips, a 125 qt full of ice that serves as an ice bank or ice donor, Wich I constantly drain, because I just want ice to last longer to refill the smaller, 50qt cooler, where I keep my drinks and food cold, and that cooler doesn't get drained as often. That works awesome for my 7-8 days fishing trips out in the middle of nowhere

Before watching, I'll give my thoughts. The cooler is a mostly closed system, and the goal is to provide as much "buffer" for heat energy to enter without warming your drinks. The ice water will be the same temperature as the ice until all of the ice is gone. The only benefit I can think of for the drained cooler is that the air pockets will act a little like snow and help insulate at least a little. My bet is water retained better sustains the cold temperature.

I appreciate the time t you took to provide a real-world, scientific test. But we all knew ahead of time that the cooler with the water would perform better because water is much less dense than air, and holds a lot more BTU's. So, it makes perfect sense that for any given volume, a dense, cold material will retain "cold" a lot better than a thin, warm material will. Every drop of cold water being released from the "DRAIN" cooler is replaced with warm outside air. Each drop contains X amount of "cold BTU's" that you're just throwing away and replacing with warm air. It's nice to see your experiment (and the graphs you showed at the end of the video) illustrated this perfectly.

No drainer here, another advantage of leaving water in is that new items put in the cooler will cool faster if they are surrounded by cold water instead of just being touched by ice in a few places

The article referenced is interesting... because as you get colder air and colder water the difference in the ice retention minimizes until you hit around 32 F (0 C) assuming pure water and at sea level, at which point there is is no more water... just ice.

Things I learned. Canyon Cooler has a representative who doesn't understand basic thermal dynamics :) RTIC I think had it right on. I would not have given their comment a point to drain as they were more of a replace than what your experiment was.

Ask any chef : 40F to 140F for 4hrs - your food ( meat, milk etc) was spoiled by that standard by day 4 - any food stored for 4 hrs between 40F and 140F should be thrown out ( commercially) , personally , you could probably double that time but only if cooking well - because bacteria grows exponentially

What I discovered on a cross country trip was this. Crushed ice melts significantly faster than an equivalent solid block of ice. So, when it comes to foods, keep a cooler with a block of ice and another for drinks with crushed ice. The crushed ice chills drinks better but foods like cold cuts tend to go bad faster in crushed ice, than with a block of ice

I once heard that a glass of ice water will remain the same temperature until the last piece of ice is melted.

Over the summer, I had my 30th HS reunion. Rest of my family couldn't make it, so I went solo, and just kept a cooler in the car. I also kept my snacks in the cooler. Among them: a pack of hard candies. They were NOT water tight. Basically, if you have anything other than well-sealed containers, don't drain it. If you have just pop...leave it.

Maybe the best test would be to measure the temperature of the coke in a can from each cooler at noon, rather than the temperature of the cooler.

River runner knowledge: only real block ice when available. I have a Clinebell ice machine for my bars so thats easy for me. Call your local shave ice stand and buy blocks. Some points: - Keep water as long as possible but KEEP IT SEPERATED from the ice! Physics is simple. Water is a much more efficient heat xfer mechanism than air. I made "stands" for my blocks out of various things. I cut down a plastic crate, turn it upside down and put the block on it. Water stays on bottom and i let the cold beverages roll around down there and put the food in baskets on top. - When you need a bev pull from the bottom. I also use fridge fans in my coolers for quicker cooling. - When the water level get high enough to touch the block, drain cold water into a bucket and pre-cool your next round of beverages before you put it in the cooler. - Keep that puppy out of the sun. - I've kept a 60 QT cooler with a single block for up to 7 Days in the desert. - Always by light-colored or white coolers. - Always look to desert rats for cooler advice. - Above is a little complex but youre welcome.

This would make a great high school science experiment. I had my expectations of what would be better, but hadn't thought through the details, and it was great to see it demonstrated in a well-designed experiment. Also, that thermometer app looks great, I think I want one.

The biggest flaw I see is that just because ice is staying around longer doesn’t mean that your food is being kept colder for longer. As you said melted ice water is only a couple degrees above freezing, even if all the ice melted into water that’s not actually going to impact the temperature of the food much. And it will retain that temperature for a long time after melting, time you completely lose by draining it.

Its definitely something interesting to think about. With water being retained, there is less overall volume of air that would also need cooled vs letting the water drain and replacing that volume with ambient temperature air.

Here's an experiment to try: fill 1 gallons pails with ice. Wait until both pails are about 1/2 ice to water, then drain one pail, leaving just the ice. Then put your hands into the buckets, one in the ice water, one with the ice. See which hand goes numb first (it will always be the ice water). Your hand is the soda.

The real trick is to leave the water in and add one eighth of a cup of salt. Putting a bag of ice as the ice melts and create saltwater top off with a second bag of ice as needed.