Hydration Part 1: Insulated Water Bottles

Insulated Water Bottles Left to Right:
Outdoor Research; Forty Below; Takeya; Hydro Flask; Primus; Thermos Titanium

An insulated water bottle can be a great piece of equipment for winter outdoor activities. Depending on temperatures and what sort of bottle you’ve got, you can keep your water from freezing or enjoy a hot drink.

I will usually take an insulated bottle with me when I’m backcountry skiing or ice climbing. Sipping hot cider or hot cocoa at lunch time provides a great feeling of well being and helps warm me up when it’s cold.

This is a review of the insulated bottles I own.

Forty Below Bottle Boot $24.95 The Forty Below Bottle Boot is made from neoprene. It’s sized to fit a 1 liter bottle. It works with a standard Nalgene bottle or, a Hunersdorf bottle. The Hunersdorf bottle is lighter than a Nalgene and has a cap design that doesn’t freeze up in cold temperatures.

The Hunersdorf bottle is also known as a Relags Bottle.

The Bottle Boot isn’t terribly effective, but it is low profile and doesn’t add much bulk to your water bottle. It’s not great for keeping hot drinks hot, but does provide enough insulation to help keep your water bottle from freezing solid. If light weight and low bulk are your priority, then this could be a good choice.

Outdoor Research SG Water Bottle Parka $70 This is a foam insulated bottle wrap. OR claims it “makes any bottle a thermos.” That’s not really true as the tests below clearly show. It is a hair lighter than the Forty Below Bottle Boot, and provides more insulation, but is also a bit more bulky. If I was just worried about keeping my water from freezing and wasn’t concerned with keeping a hot drink hot, this would be my choice.

Takeya Actives Insulated Bottle with Spout Lid $23.00 This is a basic, stainless steel vacuum insulated bottle. It comes in various sizes. The spout lid is convenient for drinking out of or pouring, but it is not insulated. I believe that the uninsulated lid is responsible in large part for this bottle’s poor performance in the testing described below. It’s not very expensive, and its performance is fine for shorter days in mild cold.

Hydro Flask 40 ounce Wide Mouth Bottle $49.95 This bottle comes in a variety of sizes. The only one I have used is the larger, 40 ounce capacity version. This bottle is well made, easy to drink or pour from, and performed very well in the insulation test. One of the best I have used, and my go-to for a larger capacity vacuum bottle.

Primus Vacuum Bottle $39.95 Note that the version I own is an older model than the one in the link. I have not used the new “Trailbreak” model. This is a nice, traditional vacuum bottle. It has a vacuum insulated double wall design, and has two caps, an inner, insulated cap, and a cover that can be used as a cup for sipping your hot drinks. It performs well at keeping drinks hot and doesn’t take up much space in your pack. I have owned two of these, and with both of them, the cup lid broke. The glue that holds the outer steel portion of the cup to the inner plastic cup failed and the two pieces came apart. It was easily fixed with a bit of JB weld, however.

Broken Primus Cup

Thermos Titanium Vacuum Bottle I can’t remember what I paid for this. I remember it being pretty expensive, I believe about $150. These bottles are pretty hard to find. They show up occasionally on ebay, but prices can be nuts (saw one sell for over $200.) This is a beautifully constructed bottle. Titanium makes it light, and it was the best performer in the insulation test. For those who simply must have a high quality titanium vacuum bottle, if you can’t find a Thermos Titanium, Snowpeak makes a smaller and lighter version, the Titanium 350ml Kanpai Bottle ($159.95) I have never used this Snowpeak bottle, but my experience with other Snowpeak gear makes me believe it is likely very high quality.

The Test

I tested the insulating qualities of each of these bottles.

All of the bottles were filled with boiling water. Then, they were left outside in the cold for 6 hours. Outside temperatures were just below freezing. After 6 hours, the water temperature in the bottles was measured.

Note that the larger containers have an advantage when it comes to heat loss, as larger regularly shaped objects generally have less surface area in relation to their volume. Having less surface area in relation to volume means that an object will radiate relatively less heat. It is likely that smaller models of these bottles would perform slightly less well. Also, all of the bottles were filled to capacity. Experience has shown that when you drink some of the liquid in a bottle, leaving empty air space, the remaining liquid tends to cool more rapidly.

Here are the results:


The two bottle wraps (Forty Below and Outdoor Research) clearly do not perform as well as the better (and heavier) vacuum bottles. They are good for keeping your water from freezing, but not really great for keeping your hot chocolate hot. The Outdoor research Bottle Parka is the winner in this category, with better insulating performance, lower weight, and just a bit more bulk.

The Takeya vacuum bottle was a bit of a disappointment. It has poor insulating performance (likely due to the non-insulating lid.) I would not choose this bottle, and would instead opt for a Hydroflask.

The Primus, while a good performer for a small bottle, was eclipsed by the outstanding performance (and lighter weight) of the Thermos Titanium bottle. The Thermos Titanium is my favorite. It is just the right size for a day trip in cold weather, it’s pretty light, and it keeps liquids hot for a long time. Unfortunately, the Thermos Titanium is very difficult (maybe impossible) to acquire.

“a perfect gear for real mountaineers”

So, the real-world winner of this insulated bottle showdown for those who can’t locate the Thermos Titanium Unicorn is the Hydro Flask. It’s easy to find, has very good insulating performance, is relatively inexpensive, and its weight is competitive with the other (non-titanium) vacuum bottles. If anyone wants a good solid vacuum bottle for keeping their drinks hot in the cold of winter, I could highly recommend the Hydro Flask.