This is my first vac pot - I ordered it after having long been intrigued by the reports of weird science and good coffee from the other geeks herein.
I had to wait a few months for it, as i "pre-ordered" it before the seller physically received it. During that time, I was unable to find any information about the "Yama HCA-5", except a picture on the yamaglass.com.tw website. (Featuring the catchy, if disconcerting, marketing slogan "No Coffee - No Pals") (Note the CG picture associated with this review may be a different Yama vac pot)
The box it arrived in had the name "Harita" all over it in large type, and in further searching of the vac pot archives on CG, it appeared to me this was a close relative of a Hario vac pot. The glass of the pot does say "yama" on it. Therefore, its pedigree remains something of a mystery.
Given its glassy nature, it was almost surprising it arrived unbroken. After gingerly removing the upper and lower brewing chambers from the box and setting them safely on the counter, i thought i was homefree when i picked up the plastic accessory bag from the bottom of the box. As it turned out, I had foolishly forgotten to turn down the earth's gravitational force in my kitchen - the bag was unsealed, and the ceramic wick holder for the alcohol lamp made a beeline for its floor tile cousins. The reunion was not joyful. As a result, my first step in making coffee with the new vac pot was mixing epoxy to try to put humpty dumpty back together again.
Reconstructive surgery was successful, at least functionally if not aesthetically. My first couple of tries at brewing coffee in it failed, the first because of missing a key part of the instructions about securing the filter, and the second because of not appreciating how quickly the brewer reacts to changes in heat once the water is "going north". In other words, this vac pot, and I assume all vac pots, require a modest learning curve to get used to the unique way they function.
By about the 5th try, I was making quite good coffee, having got some sense of the vac pot's basic function and the grind and quantity of coffee that suited it. I settled on a grind setting of "22" on the Rocky, with espresso being about an "8", the Krups Moka Brew an "18" and the Technivorm a "30". As many have reported, the vac pot coffee has a "clean" taste, which I experienced as coffee that lacked some undefined element other brewed coffee has - but the lack was not a deficit.
By comparison, I would say the coffee made by the vac pot (with limited experience) is comparable to, but not better than that from the Moka Brew. It is somewhat better than the Technivorm. But the vac pot has a signficant disadvantage in terms of complexity, capacity and efficient use of coffee compared to those other 2 devices. Coffee to my liking requires about 35g for 38 oz in the Moka Brew, and 45g for 45 ounces in the Technivorm. This vac pot requires about 40g to make 20 oz. That is because the coffee brews the same way as in a press pot - the ground coffee and hot water just kinda sit there together in the top chamber of the device for however long you see fit.
Complexity - once you have used it a few times, it isn't so much complex, as fussy. After my first few attempts, I pronounced this product to be a "class action lawsuit waiting to happen", given it is composed entirely of breakable parts, features flammable liquid and open flame as a heat source, and the shape and smoothness of the 2 glass chambers makes them susceptable to mishandling while filled with hot coffee or boiling water. However, given coffee geeks are of high intelligence and stout constitutions, perhaps this is less of a concern.
The filter is something of a pain in the bum. It is a metal disk, held in place with a spring-assisted hook, and covered with a re-useable cloth disk. At the end of the brewing, the disk is covered in grounds, and takes a few rinsings - but never seems clean, because it is stained with coffee. The instruction manual says to keep the filter in a glass of water in your fridge between uses - I personally don't see this suggestion as particularly hygienic. I have been removing the cloth from the metal disk after use and letting it dry. I think it is not too hard to just to dip it in boiling water before use to reduce bacteria. In any event, you have to deal with it, instead of just chucking it each time as you would a paper filter.
Use - the instructions are actually fairly good, considering the usual hilarity that results from translations into English. It is a bit hard to pick out the english bits from all the oriental script, but once you do, it makes sense and is helpful. MOST IMPORTANT TIP - do not try to heat a whole potful of water from room temperature using the alcohol lamp - it will take an hour. Pre-boil water in a kettle, pour into the vac pots bottom vessel, and then it will take 5 or 10 minutes for the alcohol lamp to produce the heat necessary to make coffee. It works slowly with the alcohol lamp, but this seems to be best - when I used my stove-top gas burner instead of the lamp, it was faster, but faster = disaster, as the water rushed up too fast into the top vessel and threatened to overflow. (The top vessel is not sealed). Also, you need to keep heat under it after the water from the bottom vessel has boiled up to the top vessel, so it will stay up there for a few minutes to brew. If you remove the heat, the liquid in the top will immediately drop, giving you weak coffee if you did not wait long enough. Also, the water comes up from below the grounds which are sitting in the top chamber - there is nothing to mix them , so you pretty much have to do a manual stir to make sure the grounds are all wetted.
My only complaint on the manufacture is that the clamp that affixes the brewing vessels to the stand is pinned to the stand at about a 10 degree angle - so the otherwise elegant coffeemaker has a noticeable list to it. Otherwise it seems to be "real" glass, and generally well made.
As is probably apparent, my "negative" comments really apply to vac pots generally, as opposed to this particular vac pot.