America's Test Kitchen LogoCook's Country LogoCook's Illustrated Logo

How to Clean, Purge, and Store Fresh Clams

Here’s everything you need to know about prepping these diminutive mollusks for cooking. 

Published May 19, 2022.

Clams are quick-cooking, easy to prepare, and packed full of flavor, their pleasant salinity shining in recipes like cioppino, spaghetti with clams, or Portuguese cataplana. For the very best clams, though, it's crucial to clean and store your mollusks properly. If you’re wondering how to wash your clams, how to tell if they’re fresh, or whether or not they need to be purged, read on for our comprehensive guide.

Sign up for the Cook's Insider newsletter

The latest recipes, tips, and tricks, plus behind-the-scenes stories from the Cook's Illustrated team.

How can I tell if my clams are fresh? 

Fresh clams are sold live, so you’ll find them loose or in mesh. Inspect the clams before cooking. They should smell clean like the ocean, their shells tightly closed. Gently tap the shells of any open clams and wait a few seconds; discard those that don’t close, along with any that have cracked shells or smell fishy. 

How do I clean clams? 

Cleaning the exterior of your clams is simple: Scrub the shells with a stiff brush under cold water to remove exterior mud. 

If you’ve ever received gritty clams from your fishmonger, though, we recommend also cleaning your clams from the inside, through a process known as purging.

What is purging clams, and how do I do it?

Purging is a simple and easy process that removes any interior sand from your clams, ensuring you won’t encounter any gritty bites. Here are the steps you need to follow:

1. Dissolve 2 tablespoons kosher salt for every quart of cool water in a bowl.

2. Fully submerge clams in saltwater solution.

3. Allow them to sit for 2 hours at cool room temperature, or refrigerate overnight. 

4. Carefully lift clams from bowl, leaving grit behind. 

5. Rinse again in cool water before using or storing.

How do I store clams?

Fresh clams must be stored in the refrigerator (except during purging), and storing them over ice will help them last longer. But do not store them directly over the ice, since they will die if the ice melts and they’re submerged for too long in fresh water. 

Here’s our method: 

1. Place the clams in a bowl and cover them with a wet paper towel or newspaper. This will keep them moist while also allowing them to breathe.

2. Set that bowl in a larger bowl filled with ice. 

3. Check the ice daily, replenishing as necessary. 

How long do clams stay fresh in the refrigerator?

Clams stored in the manner described above will stay fresh for up to one week.

Cataplana (Portuguese Seafood Stew)

Our cataplana captures the treasures of the Algarve region—abundant fresh seafood, smoky cured meat, vibrant paprika—in a rich, ruddy broth.
Get the Recipe

Paella on the Grill

A live fire lends Spain’s beloved rice dish subtle smoke and a beautifully caramelized crust, but it can make evenly cooking the other elements a challenge.
Get the Recipe

Garlicky Spaghetti with Clams

For a quick weeknight pasta sauce, we balance garlic’s sweet and fiery sides and then add a few pantry staples—all in the time it takes to boil spaghetti.
Get the Recipe


This is a members' feature.