What causes clumping of fine powder in a liquid?
I make omelettes fairly often. If the egg yolks are a little on the pale side, I'll add a bit of turmeric - a bright yellow finely powdered spice. Not enough to taste, but enough to add a bit of colour.
I've noticed that if I add the turmeric before I beat the eggs (so it drops on the egg-white), the powder will clump together and stay as blobs. If I beat the eggs first (with the yolk mixed in) it will spread over the surface and be much easier to combine.
If I use paprika, it will clump whether it's added before or after I've beaten the eggs.
I'm guessing this something to do with electric charge on the surface of the particles, but can someone enlighten me further.