One article describes background on a court case between Celestial Seasonings and Lipton over the use of these terms, with credit to Robert McCaleb for this account. The case is said to have been dismissed, with Merriam Webster's definition referenced as evidence that "tea" might also refer to an infusion of different herbs.
In the Merriam Webster dictionary the term "tea" includes "tisanes", as both are being used in the discussion, cited following in the online form, :
: a drink that is made by soaking the dried leaves of an Asian plant in hot water
: a similar drink that is made by using the dried leaves of another kind of plant
: the dried leaves that are used in making tea
In the same reference source tisane is "an infusion (as of dried herbs) used as a beverage or for medicinal effects" so according to them either herb tea or tisane is a reasonable way to describe something like chamomile "tea." Put another way, tea and tisane are interchangeable terms, except the other flowers and herbs themselves aren't tea, only the leaves of the tea plant are (Camellia sinensis; the third definition prior).
Oddly an unrelated court case agreed the two companies could merge without violating an anti-trust law (Celestial Seasonings and Lipton). A separate account reported that the merger failed, so it's not clear if this related to the dispute over use of terms or not.
Two separate discussions of this same issue have occurred on a LinkedIn group over the last year (Tea Enthusiasts and Entrepreneurs group on LinkedIn):
My own comment in the first of these two discussions follows:
Usually conventional use of English is a lot clearer than it is in this case. The average person in America probably isn't familiar with the word "tisane," but people working in the tea industry or just very interested in tea sometimes tend to reject using "herbal tea." A quick look at dictionary definitions of tea shows they may or may not accept "herbal tea" as valid but that clearly is the common term.
Since English is a living language that evolves through changes in use it could be argued that's the right expression based mostly on that widespread conventional use, which could change if tisane really did enter common use. More likely there would still be separate formal and informal terms for the same concept used in parallel instead since that's common.
It's even harder to get to an ideal terminology for barley tea since tisane seems to not fit either, but something like "barley infusion" is awkward and wouldn't be clear to many. In most contexts herb tea and barley tea would be fine, it would just depend.
So I didn't really commit there but it seemed like ordinary language conventions are set by actual use, and people really do seem to say "herb tea." This is also accepted by at least one dictionary, although of course likely not by all. It seems possible "tea" could be used as a broader concept in American English than in British English but I'm not claiming that, and it would take a lot of research to gather convincing evidence.
|credit quotespictures.com and William Shakespeare|
A few come to mind: soy milk, veggie burger, on-line newspaper. Of course in these cases it's difficult to imagine someone arguing for specific use of the normal concepts and terms of milk, burger, and newspaper.
Then again maybe it's odd Lipton and Celestial Seasonings took it that far too, or it would be odd to most that in conventional tea enthusiast group discussions you just can't say "herb tea," at least without someone else seeming to take offense.
But what does that mean? Those people feel a connection to the concept and expression used for tea, a personal relation to the product, beverage, concept, and word. But it also seems to be a marker for association with other people that feel the same way, or at least that have similar interests, so that a "newbie" might be readily identified by saying the wrong thing.
|she could go for a cup of tea|
"Regulars" would mention a subject others were familiar with in earlier discussion as a test of how they would react. In the source the example mentioned was the mistaken idea that glass is really similar to a liquid in that it can flow over time. If a person didn't know the actual truth of this case, that this doesn't actually happen, they would be identified as new to the group, as a newbie. Trolling here relates to the fishing practice of slowly reeling in a lure, analogous to the on-line discussion participant "taking the bait."
My understanding of the actual issue related to glass flowing or not flowing, really a separate thing, is that in earliest times glass wasn't produced at the same consistency level so thickness varied, and it was standard to put wider parts of sections at the bottom. Later observation and measurement would seem to prove the glass had flowed by an imperceptible but measurable amount, but really it hadn't (one more account of glass as an amorphous solid, in case you really want to get to the bottom of this).
It seems like the concern relates as much to one group, tea enthusiasts, identifying with a certain word use to identify themselves as it does with the confusion that the expression "herbal tea" might cause.
The broad or limited use of the concept of "tea" seems a bit insignificant since it's generally always used to include tisanes (in the broader sense) when identified with the modifier "herbal," or with the name of the herb itself. There is as little chance of any real impact as of someone accidentally buying soy milk instead of a dairy product (which I guess could happen). But then it seems possible that someone with a close enough personal connection to dairy production might regret that naming convention as well.