How to make fresh conservas

Though the title of this article may seem like an oxymoron, seafood can be easily preserved in-house, whether it’s in a restaurant or in a home kitchen. In an age where tinned fish and canned conservas are all the rage, perhaps the best-preserved seafood can be accomplished by one’s own hands and need not be purchased by the tin.

At Oloroso, a Spanish tapas restaurant and sherry bar, where Executive Chef Jason Peabody has presided over the kitchen for the past six years, you’ll find some of Philadelphia’s most extraordinary seafood dishes. There, the inherent flavors of clams, mussels, and oysters are deepened and enhanced by languishing in infused oil. Peabody’s methods arose from a need to preserve fresh shucked oysters, leftover from service at the end of the week, but they’ve evolved to encompass a larger seafood program. Peabody acknowledges the thread that links this need to the origins of canning fish during the Napoleonic Wars. He and Nicolas Appert, the “father of canning,” were both faced with the same challenge: preserving large amounts of food. At Oloroso, Peabody’s seafood never makes it into a can, but rather, onto the plate, graced with preserved lemon, fresh herbs, and a crusty, rustic piece of bread.

“Similar to how conservas were born out of necessity, we utilize our conservas as a way to maintain zero waste and present savory and delicate fish to our guests,” says Peabody (below). “The longer the fish sits in the infused oil, the more interesting and flavorful the conserva becomes.”

Preserving seafood with oil and vinegar: tips from Jason Peabody

1. For mussels, clams, and octopus, you’ll want to add acid, like vinegar. Vinegar will help preserve them, and then they technically become escabeches. Do not add vinegar to the oysters.

2. Tinned fish are delicious, and tinned tuna, mackerel, and sardines were often served at Oloroso’s bar in the past, but Peabody found that shellfish conservas could easily get overcooked in a can and begin to disintegrate. So all the shellfish conservas at Oloroso are made in-house.

3. Infuse extra virgin oil for your oysters over low heat slowly, making sure your aromatics like garlic and spices just start to bubble but do not fry. After taking it off the heat, let it infuse at room temperature overnight.

4. Shuck your oysters over a pot with a mesh strainer over it, to catch stray shell pieces but keep them separate from the precious oyster liquor.

5. Watch and taste your oyster liquor to make sure it isn’t overly concentrated. You don’t want your oysters to taste too salty. Liquor is all about flavor.

6. Don’t overcook your oysters (pay attention to the recipe below). Cook them just until they’re plump. You just want to set the protein in the oyster.

7. Save the oyster shells. At Oloroso, the cooks scrub and sanitize the oyster shells and return the preserved oyster to the shell for a truly beautiful presentation.

8. When it comes to mussels and clams, steam them just until they pop open.

9. Preserved seafood make wonderful salads, but you can also just serve them with a hunk of a crusty loaf.

10. You need to refrigerate these conservas. You can keep them in your refrigerator for up to two weeks, but they never last that long at Oloroso, they are too quickly consumed.

Oloroso’s oysters conservas recipe

Active time: 30 minutes
Total time: 24 hours
Serves: 2-4 guests

Ingredients

• 1 cup /200g mild extra virgin olive oil 
• 9 whole garlic cloves (about 35g) 
• 2 sprigs of rosemary (about 5g) 
• 2 sprigs of thyme (about 2g) 
• 2 fresh bay leaves 
• 1 stick smoked whole cinnamon 
• 1 teaspoon/2g whole black peppercorns 
• Peeled zest of ¼ lemon 
• Peeled zest of ¼ orange 
• 1 guajillo pepper (about 5g) 
• 5 cardamom pods (about 1g) 
• 2 whole star anise (about 2g) 
• 24 medium oysters (2 lbs/960g), scrubbed and shucked, with oyster meat and liquor reserved together

Method

1. The day before you’re shucking the oysters, add all ingredients (besides oysters) to a small sauce pot. Plate pot on stove over medium to medium-low heat.

2. Gently bring the oil and aromatics to a very low simmer, about 170-180°F (76-82°C).

3. As soon as it simmers, remove from heat and let cool.

4. Once oil is cool, place in a covered food safe container and allow to infuse overnight.

5. The next day, strain the oil and discard aromatics.

6. Place a fine mesh strainer over a small bowl and strain the oysters to separate meat from liquor.

7. In a small sauce pot, over medium heat, reduce the oyster liquor by 40-50%, to desired taste and salinity.

8. Add shucked oysters to the reduced liquor, returning to a simmer until the oyster protein is just set at 145°F or 63°C.

9. Immediately remove from heat.

10. Use a slotted spoon, remove the oyster and place into a food safe container (like Tupperware or a mason jar), add a bit of the liquor.

11. Cover the oysters with cooled, infused olive oil.

12. Allow to cool completely and store in refrigeration for up to 2 weeks.

13. If substituting oysters for mussels, clams, shrimp, or octopus, add ½ cup or 100g of your choice of high-quality vinegar to the product at the end.

To plate

Serve with crusty bread, crackers and roasted peppers, pickled fennel, preserved lemon, or fresh herbs.