This is not entirely the right example since this photo is taken at dusk/dawn where there’s still sunlight available. The black parts of the contrails are only black because they recieve shadows from the low sun.
Contrails at night are white (or grey as you wish) because of the white light reflected by the moon.
If there’s no moonlight they would hardly be visible or slightly from light from the ground.
Clouds aren’t black either at night right?
Just google: contrails at night
Ps. The rotational effect is causes by wake turbulence from the wingtips.