Filter your stock as much as possible. There should be no solid residues in it. Like small pieces of meat, spices, skin, etc. Warm the stock slowly in a thick bottomed saucepan.
Beat the egg whites with water and the acid.
Crush the eggshells and whisk them into the egg mixture.
Mix the egg whites into the stock, turn up the heat and bring it all to a boil.
Turn down the heat when it boils and let it simmer for 5 minutes.
Take the stock of the heat and let it cool for about fifteen minutes.
There should now be a raft of stiffened egg whites on top of the stock and the stock should be more clear.
Sieve the stock gently through a sieve lined with damp cheesecloth. If possible, use a sauce ladle to scoop it carefully into the sieve instead of pouring it. Avoid getting egg white with over the edge of the sieve.
The easiest way to get a clear stock is to avoid it being unclear to begin with. Tips: