Another thing to check, do you pre-warm the bottle? If not, it will absorb the heat of (ie, cool down) the coffee as soon as you pour it in. But if you get scalding hot water from your faucet or a kettle, pour it in, wait a minute, and dump it you will have a warm bottle that won't feel the need to take as much heat from the coffee.

Zojirushi is the GOAT as far as I'm concerned. No other brand I've used has kept my coffee hot for as long as they do.

My only gripe is that they like to over-engineer the cap/pouring mechanism in their travel mugs, which makes them tough to clean.

It's been awhile since I've had to replace one, but if I recall you want to get the plain stainless interior for coffee / tea, as it picks up less staining and odors than the coated interior.

Slightly off topic, but there is a product called Astonish, which is amazing for cleaning travel mugs and other things that collect coffee oil buildup. Its hard to find in the US at least, but can be found on Amazon.

Think you said it best in your post - you need a Thermos.

As in an actual "Thermos" branded one.

I got one of their pint sized food flasks with a folding spoon and screw on cup/lid cover that's so efficient I've got to make my coffee the night before if I want to drink it in the morning, or add cold water if I forget, otherwise it's only cool enough to drink about 12h later.

I can recommend Zojirushi, keeps hot for long and they are easy to drink from.

The metal portion should not be radiating heat. Implies there's something not quite right with the vacuum seal. If it's new, you might try returning it & asking for a replacement. If it's only mildly warm, that might be normal - have you considered getting a knit hat to place over that area to further insulate it (yes, I'm too cheap sometimes).

FWIW, I've had great luck with my Stanley thermos for doing exactly what you're doing, keeping coffee hot for hours. I also like Zojrushi's products - I have a smaller one I use to keep my creamer cold.

Klean Kanteen has worked great for me. Kept tea that my girlfriend and I made at 7:00 too hot to drink at 13:00. And that was at a snowy mountain lake – the time in between was spent snowshoeing up a mountain trail in the middle of January.

Maybe a silly question, but do you preheat the inside of your thermos with boiling water before adding the coffee from the moka pot?

If not, that small amount of coffee would be quickly cooled by the inner walls of any thermos.

Zojirushi is a good brand (Japanese but you can get their stuff in the west, e.g. on Amazon). I've only used their thermos for cold beverages, but it's rated for hot as well. Comes in 16oz and 20oz IIRC. They may have a bigger one, too.

Stanley is one of the best.

People swear by Yeti, but I think it's overpriced fashion. I kind of want one of their 12oz mugs for coffee at work. I like the style.

The problem with Zojirushi (I've owned two of the black 20 oz thermoses) is the gaskets in the cap that keep the beverage insulated at the top are prone to disclouration, after which I don't trust them. Reviews say you can, but I don't. With Stanely, the gaskets are easier to clean, remove/replace, and, I think you can easily order replacements. I don't think you can with Zojirushi. Otherwise, Zojirushi is very hard to beat.

Zojirushi official: https://store.zojirushi.com/collections/vacuum-insulated-mugs-bottles

Amazon (not affiliate): https://www.amazon.com/zojirushi-thermos/s?k=zojirushi+thermos

Target: https://www.target.com/s/mug+thermos+zojirushi

Walmart: https://www.walmart.com/c/kp/zojirushi-thermos

So, there are some options (the first four search results on DDG) and you can see what they offer. If you look at the pictures (especially on the official one) you can sometimes see the top gasket. It's kind of shaped like a pacifier, and it plugs the plastic mouthpiece you sip from. It does its job well, it's easy to remove (pulls off a straight plastic plug), but if you don't clean it several times a day, it gets these weird black spots on it. I see the black spots, I think mould, whole thing goes in the bin. Then there's the mouthpiece itself. If you remove the cap, and then place your thumb in the mouthpiece and push down, the mouthpiece pops out the bottom with a bit of force (maybe more than you're comfortable giving, but it won't hurt the lid). At the bottom of the mouthpiece is a second gasket that is hard to remove and difficult to clean. This also must be cleaned multiple times a day, or it too gets black spots and other discolourations. This having direct contact with the beverage makes it the bigger problem. Plus, you don't see it, so, "out of sight, out of mind."

I still think their thermos might be what you're looking for, just keep some way to sanitise the gaskets handy and keep them clean. People say those thermoses last a lifetime (same with Stanley) but you really gotta keep up with the gaskets.

I go thermos brand for my water, keeps it cold all day

I have this Yeti with their screw top. Work pretty well but I’ve never tested it on a 2 hour time table

One with glass insulation but those are breakable. Moka pot coffee kept hot that long will probably taste like crap anyway though.