Testing matters, prerequisites matter more...
I used various thermos models in the past, which were not belonging to a specific or well-known brand.All of them were failing while keeping cold or hot for quite a time. Some of them even leaked liquid after using for a couple of months. When I go hiking with friends, the most important thing for me is drinking my tea while water is hot enough. So this huge problem made me consider buying a pretty-known thermal bottle.
I chose Stanley 1.1qt Hammerstone Vacuum Flask.
Honestly, I was not expecting this much from a thermal bottle. Jeez! I can still drink ice-cold water even after flask was as hot as hell because of waiting under the umbrella on the beach!
I searched a little bit about how a vacuum flask is produced, and if anyone ever tore this bottle down :) I was not mistaken… someone [did.] (https://www.youtube.com/watch?v=WzutESmEJaA)
Being crafted using stainless steel and having outer body vacuumed, sure this flask can keep everything hot or cold for a long time.
I liked the shape of the flask, its color, and durability. Suddenly it became my number one tool throughout the day.
Stanley brand is over 100-year-old so it made me curious about its history, how they can still be one of the top brands in thermal bottle business. Searching about its history, I found that Stanley was founded by William Stanley in 1913 and after years it was purchased by Aladdin brand. You can still find lots of flasks people selling on eBay with “Aladdin Stanley” sticker on them. Later in 2002 Pacific Market International (PMI) purchases Stanley and moves production to China.
I was a little anxious at first because flask I will be buying was going to be “Made in China”. I googled a little bit to understand what changed since it started being produced in China. I found lots of customers on the web, forums, etc. swearing about the decrease in quality. Even it is “Made in China” which makes the majority of customers think that it has a quality problem, it did not fail me.
Most of the complaints were about a very short time it can preserve liquid hot. I understood from what I read that first thing to check was if there is a leakage on the body. You should check when you put some hot liquid inside and then if you can feel warm areas just touching any place outside the body.
On the cover of the bottle, it says it can keep it 20-sth hours hot. So as a result; some curious guys thought about testing it and there you can find lots of videos on Youtube, testing how long it can keep the liquid hot :)
I first did not bother thinking how much it can really keep my coffee hot but observed fluctuating performance. Sometimes liquid temperature decreasing quite fast and sometimes it can keep very hot for a long time.
I spotted one guy in a comment recommending putting some boiling water in the flask, keeping it there for 5 minutes, then emptying that hot water and putting coffee inside. I tested that method and I saw it working. After 15 hours my beverage was still very very hot. I think applying that will be extending the performance of any thermal keeper. When I need to carry some cold beverage, I first put ice inside the flask and then after waiting 5 minutes, I pour cold beverage on that ice. It can stay cold for hours even under sunlight on the beach! :)