Water Bottle Color Vs. Sun?
 

I've wondered for a while now if bottle color would affect water temperature on a sunny day. Has anyone looked into this? Would a white bottle stay cooler since it reflects the light rather than absorbing it, black the hottest, etc? What about the stainless bottles? Should they be the coolest if you had a mirrored surface to reflect all of the light? Though metal slides always get scorching hot in the summer, so maybe those bottles would be the hottest?

There are at least two things to consider, absorption and conduction. Darker colors will absorb more solar energy (heat) and metal will conduct heat better than say plastic or wood.

Polar bottles help with their limited insulation but they aren't much of a match for a hot sunny summer day. One trick if you want cool water when you stop is to fill a Polar bottle with just ice, no water, or even better yet freeze a half filled bottle overnight. This will limit the amount of contact between the fluid (ice) and the inside surface of the bottle, hence reducing heat transfer, then add water to the ice at a rest stop. The down side of course is that you have to carry an extra bottle.

Theoretically of course color would make a difference. If you have two water bottle cages and feel like carrying a thermometer, you can run a side-by-side test, and see if the difference is measurable.

All of my current bottles are semi-transparent or light colored. Maybe that's why.

My Arizona friends have insulated bottles with a foil wrapper under a clear plastic outer layer. The drawbacks are reduced quantity and increased weight and cost. I wouldn't carry a stainless bottle for those reasons.

As someone who trains in Houston, I've tested a fair share of the bottles. Not with the thermometer but with side by side comparison of the two or three bottles we carry. Camelback Podium Chil series is my winner and I now own 4 of these. Steel insulated work slightly better but harder to drink from and heavy.

Generally if it's hot outside, and you're riding all day, your water will get to air temperature fairly early on and stay that way. Maybe a darker color will absorb more light and get a little warmer, but I doubt it will be enough to make a difference. I did have a steel, double-walled, vacuum-sealed water bottle. It stayed cold for a long time. Multiple times I started out on a hot day with ice water, and later in the day, long after I had forgotten about my ice water, I'd make myself crazy trying to track down the clinking sound I was hearing from my bike. Eventually I'd see the water bottle and remember that the last time this had happened, it had been the sound of ice in my water bottle, and sure enough, that was the "problem" again.

Generally I just get used to drinking warm water. Makes those gas station Gatorade stops have extra appeal. But recently when touring with a small cooler, I stopped and bought a bag of ice that was far more than what I could fit in the cooler. For the next 10 miles or so, I was carrying a half a bag of ice on my handlebars and using it to refresh my water bottle at every stop. Having constant access to cold water on a hot day was bliss. Makes me think I need to replace that steel water bottle I used to have.

Bingo! Even “insulated” plastic bottles aren’t going to remain cold for that long. There is simply too little insulation to do much more than keep the liquid cold for just a little longer. There is also just too little thermal mass as well.

What if someone made a bag of some sort? And then put a cover around it? And then put some kind of straps on the bag so that it was a little easier to carry? And then made the cover out of some kind of thick material that find of serves as insulation?

Oh, wait, someone already does that. Lots of someones in fact. I agree that cold water is wonderful on a hot day. I regularly buy a bag of ice in the morning, pack most of it into a Camelbak (5 to 6 lbs), fill the rest with water and enjoy cold water for 3 to 6 hours depending on heat and humidity. The bag even feels cold on my back which provides an added bit of comfort.

And, for those are going to bring up the “sweaty back” problem, the ice takes care of that.

I use white bottles for the most part, but never gave any thought as to temperature. You can always keep water in a pannier which should help a bit. On a really hot day, I don’t want cold water, because much of it goes on my head and jersey to keep cool.

you Want a wet cotton tube sock over your water bottle to cool it .. by evaporation ..

Yup, this will bring the bottle down to wetbulb temp.
Meaning, if it's 100° dry bulb day, you put a wet sock on most anything, and if it's got a good breeze across it, then the sock will cool down to wet bulb temp (78-82 on a hot, humid day in Iowa).
But I'm not even going to guess if that's enough to actually cool the water (alot of mass there) to where we mere hoo-mans could feel it.

EDIT: I don't know weather conditions in dry states - it's possible that with 100° dry bulb and low humidity, that wet bulb could be around 60? 65? That might make a difference you could feel!

Most of the heating effect on water bottles I believe is from constant warm air flowing over it. I had some wind-block fleece left over from another project and made two bottle "parkas" to keep warm air from the surface. I also freeze half the contents the night before and find I have cold drinks midsummer for an all day ride.

Clear, just because I like to keep track of the level. That's the only thing that really matters.

When I'm doing a long ride on a hot humid day day I use Tim Horton's stainless steel thermos bottles mounted onto the main triangle of the frame. They keep the water refreshingly COLD for many, many hours. On this bicycle I have a regular water bottle mounted on the handlebar and I decant about one cup of water from the stainless steel thermos into that regular water bottle and sip from the water bottle as I ride.


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My experience riding in hot weather has shown me that darker colours are not a good idea, so only use lighter colours. How much a difference I don't know, but using the polar type ones and lighter colours makes a difference, in my opinion anyway.

I have a double-walled, insulated growler that I use the same way. Fits perfectly in my Anything Cage and gives me a nice source of ice water on a long, hot ride. And if that long, hot ride is to the brewery, than I can refill my other water bottles from the growler and bring it home full of something tastier.

Camelbak Podium Chill works great, but the Podium Ice is even better. Aerogel for max insulation. I don't then have to worry about color of my bottle so I can go with whatever looks good.

My bottles are black. Why? Cuz I ride a “hi-viz” black Surly Disc Trucker. You can’t put a price on looking good.

or you can do what I do, go with white bottles, and silver fenders, makes a really nice contrast.

Stay away from plastic, it leaches into the water in the hot sun.

I finally got the Velo Orange Mojave water bottle cage and use a GSI Microlite insulated bottle for long rides in the Arizona heat. Before I found the Mojave I used 2 16oz Contigo commuter mugs on shorter tours where I knew it would be no more than 20 miles between services. On longer tours (especially out West), I went back to my 1 liter Zefal bottles. The good is that they carry a fair amount of water, the bad is that within an hour or so the water in them is the same temp as the outside air temp.

Now with the Mojave I can carry 1 liter of water that will stay ice cold all day. For longer tours I use a Polar and the Microlight with a 3rd bottle just as backup (with the possibility of additional bottles in my trailer for long desert crossings). This has turned out to be a very good set up for me. I've even filled the Microlite with coffee heading into a campground and woken to still hot fresh coffee. After 20,000 miles of touring I am still dialing in my ride.

Obviously, a white water bottle will stay cooler than a black one on any day where it's exposed to the sun. If you want the water to stay cold, insulate it. Color doesn't matter as much then.

Camelbak Podium Ice will keep water cold for 4+ hours in +100º heat, which is more than enough-- because that bottle will be empty in less than 2 hours anyway (often significantly less.)

On cooler, sub-90º days, I've still had ice in the bottom of the bottle after 6+ hours.

I've used insulated bottles, but I'm not sure they make a noticeable difference. Although it's refreshing to drink cool water on a sweltering day, my guess is that physiologically, the human body needs fluids, whether cold, cool, lukewarm, or air temperature.

Because I drink water frequently while touring, the two (or three) litres I carry usually only lasts two or three hours. Often I approach people I meet en route and ask them to refill my bottles. Most of the time, they ask whether I would like ice added, and I always say yes! After the water has warmed up, I drink it warm!

Leaches what and at what temp?

In the West you can have chilled water all day - - cheap, easily.
A wet sock not only provides evaporative cooling, but blocks the sun.
My experience is that water is up to 40 degrees cooler - i.e. chilled.
If you keep the sock wet. It's worth it.
Insulated bottles leave you about 10 ounces and cost a bundle.
Camelback water tastes like hot plastic.
I've toured with ice-cold water for 30+ years.

Just to muddy the waters, so to speak.

We drink to replenish water lost by sweating, so maybe drinking more is better.

Cool water is more refreshing, so one might drink less before feeling satiated.

Conversely, one might drink more, warm, unrefreshing water before feeling one had had enough.

But the coolness of the water cools us down, you say.

True enough, but the big heat absorption is in the evaporation of the water, not the tiny amount absorbed in warming up the water.

Colored bottles not only look neat, as Mr. Wiggles pointed out, they hide the mold growing in them, further contributing to aesthetic appearance.

Now we need threads on leakproofness and size of the nozzle

I think that perhaps the darker the colour of the water bottle the faster the water in it might heat up. I had a white water bottle that the water in it got so hot on a long hot ride that I was able to brew green ta in it. Now I use the silver stainless steel water holders I got from Tim Horton's a number of years ago. They keep my water very cold for an all day ride in summer even when it's hot and humid. They do NOT keep things hot for very many hours during my winter ides though.

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Cheers