It seems to me that bal teshaktzu is by definition something that happens in the human mind. Nothing is objectively meshukatz; it’s all in how one thinks of it. Therefore it seems to me that the fact that the coffee looks normal, and the “drinker is not exposed to anything that would be considered m’shukatz”, should be irrelevant.
The key point is that the drinker is exposed to the knowledge of how the coffee was produced, and that knowledge inevitably creates a subjective feeling of disgust, which the drinker suppresses only because his desire for the taste is so great. And it seems to me that that suppression is what the Torah forbids.
However since the whole thing is so subjective I don’t think it can be subject to formal rules and psokim. The Creator made people different, אין דעותיהן שוות, and if someone genuinely feels no disgust at the thought of drinking this coffee — not that he has trained himself to suppress it, but that from the first he does not feel disgusted — then i t is presumably permitted for him.