Was this tea sand-roasted or roasted with far-infrared heat? The comparison is tempting, but the two are not necessarily separate methods: some sand roasting uses far-infrared heat from warmed stones. Descriptions of roasting mix the shape of the equipment, the transfer of heat, and the relationship to the flame. Untangling the names helps explain what the machinery does.
How tea is heated and how it moves are separate questions
A rotating drum describes the vessel holding the material and its movement. Far-infrared describes a way of delivering heat, while direct fire describes the relationship to the flame. “Rotating drum or far-infrared” is therefore not necessarily an either-or choice; some machines use both.
It is similar to thinking separately about a frying pan’s shape and the appliance heating it. When reading a product description, distinguish what holds the material, how heat reaches it, and how it moves. This helps organize the differences behind similar-sounding names.
In sand roasting, heated stones transfer heat to tea
Chaho Furyu describes sand roasting as a traditional method using far-infrared heat from warmed stones. The shop aims to heat the tea evenly and draw out sweetness without scorching it. Look beyond “sand” in the name to the explanation of how stones carry the heat.
Yanoen uses both a sand roaster and an infrared finishing machine in the stage where blended tea receives further high-temperature heating. One shop does not necessarily use just one method. Read the choice of equipment in relation to the finish the producer wants.
Turning a drum to roast the material evenly
Marubishi describes its rotating-drum method as roasting evenly while the drum turns. Rotation speed and temperature can be adjusted to suit the material, and the method is mainly used for hojicha. A temperature and time alone leave out how the material moved.
Yamamasu’s far-infrared rotary finishing machine heats tea with near-infrared and far-infrared radiation from a blast burner inside the rotating drum. This is a concrete example of combining rotation, which moves the material, with infrared heating.
Some grain roasters blow hot air upward
Marubishi also describes a method for grains such as Job’s tears and black soybeans that blows hot air upward from below. The company says it provides even roasting and stable quality and is suited to mass production. Even under the general name “roaster,” the explanation changes with the material being processed.
Meanwhile, Minocamo Chaho’s Direct-Fire Deep-Roasted Hojicha is described as tea stored at low temperature for one year, then slowly deep-roasted over direct fire. Here, the way the material is handled beforehand, as well as the heating method, helps communicate the taste.
A machine’s name alone does not determine the tea’s taste
Before concluding that far-infrared heat must produce a particular taste, look at whether the tea uses leaves or stems, how the material is handled, how rotation and heat are adjusted, and the intended finish. Products do not have identical descriptions simply because they use the same method.
The tastes and performance described here come from the tea merchants and equipment manufacturers. At a shop, the useful question is what the producer hopes to achieve with the equipment, rather than which tool is superior. Asking “What do you adjust the heat to account for with this tea?” moves the conversation from machine names to the producer’s judgment.