Why does my sodium acetate look like metalic magma? I tried to make sodium acetate.  

Ingredients:


Store bought vinegar - 8% acetic acid, water, E150C  (caramel)  
Baking soda - $\ce{NaHCO_3}$   


Steps:


I first emptied sacks of baking soda to a container
I kept adding vinegar until the resulting fuming was mild
I started heating the solution slowly, I kept adding more vinegar as long as I could see bubbly reaction
I increased heat until all water evaporated. I was left with white-brown chunks of (presumably) sodium acetate and the impurities from vinegar
I kept heating this until it melted into opaque black liquid
I poured the hot molten stuff into ceramic bowl


This is my result:



I might upload better picture tomorrow, when there's more light available.

So, this does not really look as sodium acetate at all. It looks like a volcano. Clearly there's more volcano-ish experiments with vinegar than I thought.

How do I purify this? Is there even any sodium acetate? Could I burn (decompose) it or something?
I wouldn't bother trying to purify it. As Mithoron said in his legendary comment "Caramel made your product a black unholy abomination of science". I would have distilled the vinegar and diluted it (because concentrated acetic acid is a bit dangerous if you don't know what you're doing) and start again. If you want pure product, make sure your starting materials aren't filled with "unholy abomination of science" causing impurities. If you really want to purify it, maybe recrystallise it in hot water? Or a solvent that sodium acetate can become saturated in.