Best small coffee thermos on the planet is......
- Thread starter Dene
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Yellowstone
New member
Greg - when it comes to Stanley thermos, older is better. If you can find and deal with their first generation of two quart thermos (no handle and heavy and awkward) it will keep coffee hot for over 24 hours. Trouble is finding someone who will part with theirs - or hitting garage and estate sales. Nissan makes a two-cup bottle that does pretty well if pre-heated.Yellowstone
Not For Hire
New member
The Stanley thermos of 1 qt or more capacity is a dandy. I have two and they keep liquids hotter, longer than Thermos brand and Nissan brand. I use them ice fishing and etc. My favorite has a small dent from being run over with a Jeep Cherokee years ago.
But the question of a smaller thermos is a good one. I have some of those also and none seem that sturdy or keep things hot that long. When backpacking, turkey hunting, etc., I want a small thermos, don't want the heavier 1 qt. variety.
So how about a one pint thermos?
Mark
But the question of a smaller thermos is a good one. I have some of those also and none seem that sturdy or keep things hot that long. When backpacking, turkey hunting, etc., I want a small thermos, don't want the heavier 1 qt. variety.
So how about a one pint thermos?
Mark
starcrafttom
Active member
just read the coffee at starbucks goes for $55 a gallon. switch to diat coke for your caffine needs and save money. :wink:
Maybe I can save Joe the trouble 
The heat content of the coffee is proportional to its volume, and it loses heat at a rate proportional to its surface area. To conserve heat you would like a high ratio of volume to surface area, i.e. for a given volume the smallest possible surface area. The shape which solves this problem is a sphere, but I haven't noticed any spherical thermos jugs in WalMart. They are all cylinders so I guess we'd better look at that case. If the radius is R and the length is L the volume is proportional to L x R x R and the surface area is proportional to L x R. The ratio of volume to surface area is proportional to R so if you have 2 cylinders and the radius of one is half the radius of the other, the smaller radius one will be half as 'good' as the larger radius one. What if you keep the same radius and make the cylinder half the length? Then the two cylinders have the same ratio of volume to surface area and are in that sense equally 'good'. Maybe Joe can straighten me out on this but it seems that it is better to cut the cylinder perpendicular to its length to reduce it rather than reduce its radius. A shorter thermos would seem better than a longer one of the same volume.
The heat content of the coffee is proportional to its volume, and it loses heat at a rate proportional to its surface area. To conserve heat you would like a high ratio of volume to surface area, i.e. for a given volume the smallest possible surface area. The shape which solves this problem is a sphere, but I haven't noticed any spherical thermos jugs in WalMart. They are all cylinders so I guess we'd better look at that case. If the radius is R and the length is L the volume is proportional to L x R x R and the surface area is proportional to L x R. The ratio of volume to surface area is proportional to R so if you have 2 cylinders and the radius of one is half the radius of the other, the smaller radius one will be half as 'good' as the larger radius one. What if you keep the same radius and make the cylinder half the length? Then the two cylinders have the same ratio of volume to surface area and are in that sense equally 'good'. Maybe Joe can straighten me out on this but it seems that it is better to cut the cylinder perpendicular to its length to reduce it rather than reduce its radius. A shorter thermos would seem better than a longer one of the same volume.YACD is correct about a sphere being best and depending upon how eager you are for the thermodynamic optimum you can find an approximation here;
http://www.finemech.com/kgw_isotherm/sp ... asks.shtml
bit pricey though.
http://www.finemech.com/kgw_isotherm/sp ... asks.shtml
bit pricey though.
A good friend of mine graduated from Stephens Inst. Technology (Ph.D. Physics; cryogenics), and I met him when he started at NASA Ames at Moffet Field in Mt. View, CA ~ 1978. He designed an ultra-low temp device for the Infrared Astronomical Satellite (IRAS) --they hoped IRAS would last 3-4 months before the liquid helium ran out. Surprisingly (and largely due to Walt's contribution), it lasted about 8 months, and as a result, collected more astronomical data than had been collected in the previous history of mankind! (before Hubble, of course.)
[Walt went on to lead NASA's supercomputing division, and supervised the development of the world's fastest computer about 6 years ago (since surpassed, of course). His computer was the one used to model the probability of the 3rd shuttle disaster after it lost those tiles a few years ago, but of course that's another story.]
We visited the Smithsonian Air and Space Museum a few years ago, and there was a second copy of Walt's "thermos bottle" -- pretty cool! (no pun intended).
If you really want thermal insulation, I could ask Walt if they have any others left over. However, if you thing those Dewar flasks are expensive . . . . !! :shock:
iggy
[Walt went on to lead NASA's supercomputing division, and supervised the development of the world's fastest computer about 6 years ago (since surpassed, of course). His computer was the one used to model the probability of the 3rd shuttle disaster after it lost those tiles a few years ago, but of course that's another story.]
We visited the Smithsonian Air and Space Museum a few years ago, and there was a second copy of Walt's "thermos bottle" -- pretty cool! (no pun intended).
If you really want thermal insulation, I could ask Walt if they have any others left over. However, if you thing those Dewar flasks are expensive . . . . !! :shock:
iggy
YACD":s665vo29 said:
Is there an engineer in the house? :lol:
Apparently few engineers at Zojirushi, however -- probably too many marketing types who come up with the tall skinny thermos referenced in a later posting.
That said, my Zojirushi coffee maker is the best I have ever owned. it drips into a steel carafe.
Warren
I am not an engineer but- I have several thermos bottles of various brands and they all perform well. Even the small skinny one. The secret to better performance is preheat the bottle before adding your beverage and most importantly store the thermos vertically. Heat is lost rapidly through the lid when the thermos is horizontal. Most any thermos will keep coffee hot for 6-10 hours when stored vertically.
For the best, that i know of, go to WWW.HAMMACHER.COM. ITEM 74963.Dene":37v299kl said:
YACD":3akw3zdw said:Maybe I can save Joe the trouble
All 100% correct! An A+ for your paper!
The ratio of volume to surface area is the absolute ruling factor for a given design.
Your explanation is as good as I can write from a mathematical point of view, and easy to follow for those with some math inclinations.
The same ratio of surface area to internal volume can be seen in animals. We'll use a deer as an example, at first.
A big deer from a northern climate like Maine and a small deer from Florida of the same species look to the casual observer to have the same body plan, proportions, and probable surface area ratio to internal volume, but not so!
The deer's internal dimensions, when multiplied, rise as a product of length times width, times height, or with the cube (third power) of the dimensions.
At the same time, the surface area of the deer rise as length times width, or with the square (second power) of the dimensions.
Thus larger deer have much more internal volume to generate and contain heat in proportion to their surface area. They generate more heat, and have less surface area through which to lose heat.
This accounts for why a deer of a given species may weigh 250 lbs in Maine, but it's same species cousin in Florida may weigh 90 lbs. There the same species, but natural selection on a local basis has selected the larger animal (with it's genes) to survive better in Maine's cold winter climates, whereas the Florida relative doesn't need this otherwise cumbersome size to tolerate the winter cold.
This same phenomena can be seen in most all animals. Think of the common arctic and near arctic animals: polar bears, walruses, whales, moose, caribou, musk oxes, giant brown bear, elephant seals, etc. All are very big to survive the cold arctic conditions, even considering migration habits.
The same thing happens during the ice ages. Animals evolve over the short term to survive the conditions. The wooly mamouths, saber tooth tigers, buffalo, wolves, and a host of other animals evolve over the 10,000 year or so period from smaller species to better survive the cold conditions, then when the Earth goes back through a warming cycle, the process reverses an they get smaller or are replaced by other smaller species.
Of course their are exceptions, but bigger animals survive better in colder climates.
Your 289 lb brother will have a much easier time staying warm in Nome, Alaska than you with your Charles Atlas reject 98 lb bag skin and bones.
Russian men seem to prefer very large, heavily built (warm) wives. With one of them and a healthy supply of vodka, the winter may just not be so hard to bear!
The Russian practice may not too bad a substitute, I guess, when central heating and cheap fuel are not readily available. Do you suppose that's a viable plan for Americans with the rising fuel/energy costs? :cocktail :cocktail :cocktail :crook
Joe. :teeth :thup
oldgrowth":trc1iej3 said:“a bit pricey”McDipple":trc1iej3 said:
I would say that is a bit of an under-statement. I believe $316 for a one liter thermos is dammed expensive.
_______
Dave
Those weren't designed or intended for retail use. Their primary purpose is for storing/transporting liquid nitrogen in scientific labs.
Doryman":orw6r3qb said:CAVU":orw6r3qb said:
Well, duh! I am an idiot. In light of the preceding discussion, that makes eminent sense, but now I realize I have been doing it wrong all along.
Thanks!
Warren
Me too. I've learned a lot about thermoses. I intend to keep my Stanley vertical and preheat it, before adding the coffee. We'll see if that increases
it's efficiency.
-Greg