When cooking vegetable broth what is the scum that comes to the top? It's not fat.?

Question

What is the scummmy stuff that always comes to the top of vegetable soup and broth, like a froth? I cooked vegetable soup last night, with 2 cans of diced tomatoes, and the froth came to the top during boiling. I scooped it off, but what is it, and why does it appear?

Answer 1

Being a former professionally trained chef, it happens with all stocks like meat, veg anf fish, it is correctly a protein issue, but can also be from cooking it to quickly, on to high a heat, things break down to quickly and tend to release the impuritys and this can cause the foam, scum or residue.

Try next time to bring the broth to a boil and lower the heat to a bear simmer, you can cook it longer and extract more flavours, to hot and the veg or other materials breakdown before they have got there full nutrients released.

I made my share of stocks over the 20+ yrs I was a chef, mind you we had steam kettles that are easier toregulate but it works for the stovetop also.

Answer 2

Scum is a layer of greyish, foamy, coagulated protein and dirt which rises to the top of a simmering liquid. You did the right thing by skimming it off. When preparing stock, both the scum and fat should be skimmed off.

Answer 3

I think that it is protein and sugar and fiber. When the cell structure of a food is cut in half the stuff inside leaks out and floats to the top.

Answer 4

fruit grows on shrub or vines and fresh vegetables grow in the land.

Answer 5

Yes, that's right, it's just minuscule parts of the soup ingredients.

Answer 6

scoop it out it's extremly fatty it's all the fat and access oil that evaporates when u cook it scoop it all off it's not healthy