When I make chicken stock from scratch, I like to include whole spices like mustard seed, coriander, star anise and black pepper. I put these in right at the start when the water is still cool, so they can slowly add flavor as the stock simmers for hours.
I only run into a problem when skimming foam. Many of the whole spices float to the top and I find it very tedious to skim the foam without taking out spices as well. I use a metal spoon or ladle for skimming.
How can I skim the foam without catching the floating spices as well? Is there a technique or tool specially suited to this task?