Fill a steamer basket with the clams and place inside a large stockpot. Add 1œ cups water, cover and place over high heat. Let steam 6 minutes. Uncover and remove any opened clams and set them aside. Cover again and steam the remaining clams another 2 to 3 minutes. Remove the opened clams and set them aside. Discard any that do not open.
Pour the liquid in the stockpot through a fine-mesh sieve lined with cheesecloth or a large coffee filter. Reserve the liquid, adding enough clam juice to make 2 cups. Set aside.
Remove the meat from the cooled clams and set aside. Reserve the shells.
In a clean stockpot over medium heat, warm the olive oil and sweat the celery, onion, leek and fennel until soft, 10 to 12 minutes. Add the garlic and saute until fragrant, 1 to 2 minutes. Do not brown the vegetables.
Add the wine and raise the heat to medium-high. Let simmer until the wine is almost evaporated, 1 to 2 minutes.
Add the reserved clam juice, clam shells, peppercorns, bay leaf, thyme sprigs and 3 cups water. Bring to a boil over high heat, then reduce the heat to low and simmer gently 30 minutes. The broth should smell like the ocean and taste mildly salty.
Carefully remove and discard the solids, then strain the liquid through a fine-mesh sieve lined with cheesecloth or a large coffee filter. Let cool and refrigerate overnight.
4½ cups water, divided
½ cup clam juice, plus more as needed
2 Tbsp. olive oil
2 celery ribs, diced
½ medium onion, diced
½ leek, white parts only, sliced
¼ fennel bulb, diced
1 clove garlic, minced
¹∕³ cup dry white wine
8 peppercorns
1 bay leaf
3 to 4 sprigs fresh thyme
This article appears in Guide to Beer 2015.