The Food Lab: Better Home Cooking Through Science

2 bay leaves
2 teaspoons whole black peppercorns
1 teaspoon fennel seeds
1 teaspoon coriander seeds
6 sprigs fresh parsley

1. 
   

    Pour    4   cups    of  water   into    a   medium  bowl    and sprinkle

   
   

   with the gelatin. Set aside until the gelatin is hydrated,
   about 10 minutes.

   
   


2. Meanwhile, put the onions, carrots, celery, leek,
   mushrooms, apples, bay leaves, peppercorns, fennel,
   coriander, and parsley in a large Dutch oven or stockpot
   and add cold water to just cover the ingredients. Add the
   hydrated gelatin and water and bring to a simmer over
   medium heat. Adjust the heat to maintain a slow, steady
   simmer and cook for 1 hour, adding hot water as
   necessary to keep the ingredients submerged.


3. Strain the stock through a fine-mesh strainer lined with
   cheesecloth into a large bowl and discard the solids.
   Return the stock to the pot, bring to a simmer, and reduce
   to 2 quarts, about 20 minutes. Remove from the heat. The
   stock will keep in an airtight container in the refrigerator
   for up to 5 days, or it can be frozen for up to 3 months
   (see here).