Okay so during my childhood in Bulgaria I had an idea.

That we could mix instant coffee powder in fruit juice, as long as that fruit juice is from a sweet ripe fruit.

My father tried it and he liked it, he asked his friends and they said this has already been done before. However it loosens you too much.

I only told him one thing. "What if we don't use any water in it and we leave it in the fridge in the bottle of juice as a cold brewed coffee?"

He was skeptical but we did that and he never got diarrhea from it.