I made some turkey stock yesterday, with my stash of frozen turkey bones from this stand-by recipe, and accidentally allowed the stock to boil while I was up in the loft, tending to the seedling garden. I had read somewhere that you should never let stock boil, as it emulsifies the fat, which causes the cloudiness, and since the fat is dissolved into the water of the stock, it will not separate out on cooling, and will not be sieved out with a cheesecloth strain. It did seem to be holding true for at least an hour, as it was simmering away, and was still quite translucent, until I remembered that I really needed to water the seedlings. So after some harumph-ing and a little swearing, Tai suggested that I “raft an egg white” on the stock to clarify it. (Sometimes his culinary training really does come in handy!) Of course, those weren’t the most specific technique directions in the world, so I got back on Ye Olde Internets and Googled “chicken stock cloudy egg white” et, voila! Lots of advice from many more well-informed cooks than I. (I subsequently updated my Rich Chicken Stock recipe, which had called for a rolling boil!)
The technique is quite easy and the effect is actually rather cool-looking. Basically you combine an egg white with boiling, strained stock, and the albumin in the egg white acts like a vacuum for the solubilized fat, binding it and allowing it to be drawn out of the stock. Science & cooking: I love it when my two worlds combine! I found that a little of the fat snuck through the sieve anyway (as it was hard to keep it from breaking up during the last straining), but I imagine if I wanted a crystal-clear stock I could repeat the process.
I saw this advice, or variations thereof, on various sites, but I think the below formula was drawn from Chowhound.
Clarifying Cloudy Stock
For each quart of stock:
- 2 tbsp cool water
- 2 egg whites
- crushed egg shell from 2 eggs
- 1/2 tsp lemon juice
- Strain the stock through several layers of cheesecloth to remove any bones, meat, etc. Clean the stockpot, and return the stock to the pot.
- Mix the ingredients together and add to the stock. Bring to a boil over high heat, then remove from heat, covered, and allow to rest for 15 minutes.
- Strain once more through rinsed cheesecloth, taking care to pour slowly and carefully such that the fat does not re-solubilize. Update: Tai says that you can make a tube out of doubled-up tinfoil, slide egg/fat bits out of the way of the tube, push it to the bottom of the pan, and then ladle the stock up through the tube to keep the egg/fat from breaking apart back into the stock. Store as per stock recipe.