Comment by klausa

It's the "other stuff"/flavor compounds, definitely.

I don't think brewed coffee contains any meaningful amounts of sugar?

Coffee (filter/brewed, not espresso) is ~98.5% water by weight, even if the Eugenioides species has more sugar in the beans than Arabica (it might! literally no idea here) — if the difference would be "just" down to the sugar levels, I don't think it would be noticeable at the dilution levels we're talking about.

The difference in the natural sweetness vs adding sugar is an interesting question, honestly!

Sugar is usually added to coffee to hide/mask/round out the bitterness; whether naturally occurring or from overly developed roast. But it also masks/drowns out other notes, too. You'll get less bitterness, but less of the acidity, the floralness, of all the other subtleties that can make coffee great — you'll get _sugar_ sweetness (and it's a very different kind of sweetness than coffee can naturally have!), and less of everything else.

Eugenioides is different because it just doesn't have that baseline note of bitter/hashness _at all_, and it's naturally pretty sweet.

Instead of sugar, I think the "magic berries" (I never tried!) that mess with your bitterness perception might work better? I'm actually now curious to try it out...