Even some young Japanese tea fans mistake this mark of fine quality for insufficient cleanliness.

Japan is a nation of unapologetic foodies. Customers hold restaurant fare to strict standards, and since restaurant operators know that, the ones who want to succeed make sure their food and drink is of the highest quality.

However, that strategy recently backfired for Japanese Twitter user and restaurateur @ichi4649. It seems a young customer came into @ichi4649’s establishment and ordered a pot of green tea. However, after the tea was poured, the customer quickly sent it back, deeming it undrinkable.

What was the specific complaint? Well, after staring into the cup, the customer exclaimed “There’s dust or something floating in this tea!” And indeed, looking at the above photo, there does seem to be some sort of particulate matter in the beverage.

However, this isn’t the result of using old or improperly stored tea. Just the opposite, that photograph is evidence of @ichi4649’s commitment to quality, because that’s not dust, but trichomes.

For those who took geology class instead of botany, trichomes are filament-like growths that appear on the outer surface of plants and protect it as it grows. They’re found on all tea leaves, and are particularly prevalent on delicate, newly sprouted tea leaves.

The tea served at @ichi4649 restaurant didn’t have so many trichomes because the cup was dirty, but because it was made with young, freshly harvested leaves, which are the most prized due to their scarcity and robust flavor.

Unfortunately, even after the staff explained what the trichomes were, @ichi4649’s customer was still unsatisfied, and promptly stormed out of the restaurant. @ichi4649 says this is a recurring problem when a fresh crop of tea comes in, but on the bright side, that means more fresh leaves to be enjoyed by those in the know.

Sources: Jin, Immortalitea, Twitter/@ichi4649

Follow Casey on Twitter, where he could actually go for some green tea right now.