This vacuum bottle has a relatively small diameter lower section and larger diameter upper section to hold a whopping 30 ounces of liquid. It is made of 18/8 stainless steel which means it is made of 18% chromium and 8% nickel, same as used in high end stainless tableware. It is extremely unlikely to stain or rust and the nickel makes it very strong. Often people don’t realize vacuum bottle is the generic term of a trademarked product called Thermos™ Bottle. This Built in NY container is 8¼ inches tall and just a little under 3 inches in diameter at the bottom and just under 4 inches in diameter at the top. It holds a 30 ounces of liquid. That’s just a little less than 4 measured cups of water, not a coffee size mug. Most coffee mugs hold upwards to two cups of water, so think of it as almost two coffee mugs. Oh, be sure to scroll down to see my temperature test chart. This vacuum bottle fits in the cup holder in the center console of my late model Honda Accord quite easily – probably an industry standard size. Look at my photos so you get an idea how it fits. This vacuum bottle has a sliding rotating top to open access to a small opening that a flexible plastic straw can pass through. However, a common straw would just fall completely inside. You’d need an extra long one. I have some long glass straws that can almost fit through the opening. However, even though the glass straws are longer, it would probably slide and fall inside as well. So the only viable method is using your lips and the age old technique of drinking from a tall bottle or glass. You might find an extra long straw the next time you go to your favorite fast food restaurant. Perhaps recycle it by taking it to your car instead of throwing it into the trash. I wouldn’t recommend drinking coffee through a plastic straw, however – hot liquids can possibly leach undesirable chemicals out of the plastic and into your mouth. Glass or stainless steel is safer from a chemical standpoint. Naturally, glass is breakable as evidenced by a 55 year old scar still visible in the palm of my right hand from chemistry class. The following chart will give you some idea of its ability to keep the contents cool. I keep my refrigerator at 38° F and keep a lot of bottled water inside. I put this vacuum bottle in the deep freezer at -8° F overnight, so this contributed to a slightly better start, but longer term, it didn’t contribute much for very long. You will notice that the warmer the water becomes, the less the temperature changes per hour. That is because the water is getting closer to the outside room temperature of 75°. So there is less temperature difference between inside the bottle and the outside. Therefore there is less temperature differential between inside and outside. Eventually the inside and outside temperature will become virtually the same – given enough time. Starting Temperature: 37.7 degrees F. 44.6° after 3 hours…..… Gain of 6.9° - not bad considering a plastic lid 48.7° after 5 hours…..… Gain of 11.0° Overall 50.5° after 7 hours…….. Gain of 12.8° Overall 55.2° after 9 hours…..… Gain of 17.5° Overall 58.4° after 12 hours…… Gain of 20.7° Overall 64.0° after 20 hours…… Gain of 26.3° Overall I haven’t tried this vacuum bottle with coffee because I’m not much of a coffee drinker, but I do like to sip ice cold water in my car for even relatively short trips. So I did a temperature test to test how well it keep the water cool. The test was done with an ambient temperature of about 75 to 76 degrees in my house, so that is a fairly benign temperature environment. What I learned is I will need to add some ice cubes to keep the water temperature low enough for my preference for ice cold water. Now if you are starting off with very hot coffee, the temperature change will be faster than the chart above would indicate – because the coffee temperature compared to the room or ambient temperature will normally be much greater. Unless you are storing this vacuum bottle in a hot car in August, that would be the case. The rate of temperature change is a direct correlation between the inside and outside temperature difference. The greater the temperature difference, the faster it will heat up or cool off the liquid inside. It’s just physics. The bottle materials and overall construction do have some to do with how fast this occurs, but these days, the concepts are well understood and there’s not a huge difference in thermal design. Lid designs do have an impact on thermal gain or loss. A true vacuum bottle usually has an insulated stopper that protrudes into the bottle. But this Built NY lid is quite clever. In a way, it is double insulated by creating a small air gap by way of the slider that snaps into the center of the lower part that seals against the opening of the vacuum bottle. Furthermore, it doubles as a way to greatly reduce leakage if you tip it over – if you grab it in time. However, no matter how fast you are, it will spill some liquid – just a matter of how much. They left an air gap so air can get inside as you drink the liquid to make it easy to gulp your drink faster. To make it easy to clean, you just unsnap the lower center by pressing on it and you get two easy to clean plastic disks.
