How to Store Anchovies Once Opened: A Guide to Make Them Last Weeks

The most frequent question we receive after "what anchovies do you recommend" is this: "I've opened the can and haven't eaten all of them — what do I do now?"

It's a legitimate question. A can of quality Cantabrian anchovies costs between 7 and 15 euros. If they spoil due to incorrect storage, it's an unnecessary waste. And it happens more often than it seems: people open the can, use 4 fillets, and leave the rest exposed in the fridge, only to discover two days later that they smell strange or that the texture has changed.

Having spent 35 years in Barcelona's Mercat del Ninot selling preserved and seafood products has given us a very clear perspective on the most common mistakes and how to avoid them. This guide covers everything you need to know to make your anchovies last well once the can is opened.

Why Anchovies Spoil Once Opened

To understand how to store them well, you must first understand why they spoil. Canned Cantabrian anchovies are a cured product — transformed by salt and time — but they are not indestructible once the contents are exposed to the outside.

There are three main mechanisms of spoilage:

Oxidation: the olive oil in which they are preserved oxidizes upon contact with oxygen in the air. This process produces organic compounds that give a rancid flavor and unpleasant aroma. It is the fastest and most common spoilage. A "well-cured" anchovy with oxidized oil tastes bad even if the fish itself is not spoiled.

Microbial contamination: although the acidic and salty environment of a preserve is hostile to most bacteria, once opened and exposed to room temperature or unclean utensils, the risk of contamination increases. It is not the most immediate risk — salt acts as an effective barrier — but it exists, especially if the preserve is handled with dirty cutlery or kept at high temperatures.

Dehydration: anchovy fillets exposed to air without oil cover dry out. The texture, which in a good anchovy should be firm but tender, becomes hard and leathery. The flavor intensifies unpleasantly — more salt, fewer nuances. A dry anchovy is not unhealthy but is a much worse experience.

The common denominator of all three mechanisms is the same: exposure to air. Eliminating that exposure is the key to any preservation strategy.

Method 1: Store in the Same Can with Covered Oil

The simplest and perfectly valid method if you are going to consume the rest in less than 3 days. The protocol is as follows:

After removing the fillets you are going to eat, make sure that those remaining in the can are completely covered in oil. If the oil level has dropped after removing fillets, add extra virgin olive oil until it completely covers the surface of the remaining fillets. No part of the fillet should be in contact with air.

Cover the can with cling film, pressing directly onto the oil's surface (without leaving an air pocket between the film and the liquid), or use a piece of aluminum foil folded several times to seal well. Store in the coldest part of the refrigerator, which is usually the central area or the vegetable drawer.

Maximum duration with this method: 2-3 days. The metal of the can, once opened, can transmit a metallic taste to the oil, which limits the storage time even if the product is not microbiologically spoiled.

When to use it: when you have few fillets left (3-4) and you know you will consume them in 2 days. For larger quantities or longer periods, use method 2.

Method 2: Transfer to a Glass Container (the Ultimate Method)

This is the method we recommend as standard at Bacalalo and the one professionals use. An airtight glass container — not plastic, as glass does not absorb odors or flavors — is the ideal container for storing opened anchovies.

The step-by-step process:

1. Choose a glass container with an airtight rubber seal. The size should be just right for the contents — the smaller the air space between the fillets and the lid, the better.
2. Clean and dry the container completely. Not a drop of water should remain — water and oil do not mix, and moisture can promote oxidation.
3. Transfer the fillets carefully, arranging them in horizontal layers, not irregularly stacked.
4. Cover completely with the original can oil. If there isn't enough oil, top up with extra virgin olive oil.
5. Make sure no fillets protrude above the oil level. All must be completely submerged.
6. Close hermetically and store in the refrigerator.

Maximum duration with this method: 5-7 days with optimal quality. Under ideal conditions (refrigerator calibrated to 4 degrees, completely airtight container) they can remain in good condition for up to 10 days, although after day 7 the texture begins to change slightly.

Leftover oil: don't throw it away. The oil from a quality Cantabrian anchovy preserve has an extraordinary flavor — salty, with umami, with the nuances of curing. Use it to dress salads, to dip bread, to add depth to a vinaigrette. It is a top-quality cooking ingredient.

Method 3: Wrap in Film (for Very Short-Term Use)

There are situations where you don't have a glass container available and need a temporary solution to store a few fillets for a few hours or at most one day. In that case, food film is an emergency option.

Place the fillets on a piece of food film. Add a generous drizzle of extra virgin olive oil directly over the fillets. Wrap with the film, ensuring the oil covers all the fillets and no areas are exposed to air. Fold the ends down to seal. Store in the refrigerator.

Maximum duration: 24 hours, ideally less than 12. This method is not ideal because the film does not seal perfectly, and the oil can leak. It is only a temporary solution.

What you should not do: store fillets wrapped in film without oil. Without the oil barrier, the anchovy oxidizes and dries out in a few hours, even inside the refrigerator.

How Long They Last with Each Method: Reference Table

Important note: these durations assume a properly calibrated refrigerator between 2 and 5 degrees. A refrigerator at 8-10 degrees halves all these times. If you don't know your refrigerator's temperature, it's worth checking — most household refrigerators are above their optimal temperature.

Signs That Anchovies Are No Longer Good

Knowing the signs of spoilage prevents you from consuming a product in bad condition and helps you know when an anchovy has passed its optimal point even if it is not technically "bad."

Clear signs of spoilage — do not consume:

• Rancid smell or oxidized oil when opening the container. Old oil has a characteristic smell similar to wet cardboard or paint.
• Grayish or greenish color on the fillet. The amber-brown color should be maintained. If there are gray or strange-colored areas, it is a sign of alteration.
• Extremely soft, almost disintegrated texture. An anchovy that falls apart when touched without any resistance indicates advanced spoilage.
• Visible bubbling in the oil. Indicates microbial activity.

Signs that it has passed its optimal point but is not dangerous:

• Harder texture than normal, somewhat leathery. The anchovy has partially dehydrated but is not in bad condition. It loses quality but is edible.
• Salty and more intense flavor than usual. Over time, the salt concentrates. It is still edible but the experience is less balanced.
• Slightly cloudy oil. In the refrigerator, olive oil always becomes cloudy — this is normal and not a sign of a problem. If the cloudiness persists at room temperature, it may be the beginning of oxidation.

When in doubt: the rule is simple. If the smell is not right, do not consume it. Bad anchovies smell unmistakably different. Your nose is the best detection instrument.

Can Anchovies Be Frozen?

This is a question that generates debate and deserves a nuanced answer.

The technical answer is yes, anchovies can be frozen. The practical answer is: only as a last resort, because the result is not comparable to the fresh preserved product.

The problem with freezing is the texture. Anchovies have a delicate protein structure that is affected by the ice crystals that form during freezing. When thawed, the texture becomes soft, mushy, and completely loses the firmness characteristic of a good Cantabrian anchovy. The flavor is maintained better than the texture, but the overall experience is disappointing.

If you decide to freeze anyway (for example, you have a large quantity that you know you won't consume within the week), the correct protocol is:

1. Separate the fillets individually on parchment paper on a tray.
2. Freeze in that position until solid (1-2 hours).
3. Transfer the now solid fillets to an airtight freezer bag, removing as much air as possible.
4. Mark with the date. Maximum duration in the freezer: 3 months.
5. Thaw in the refrigerator for 12 hours. Never at room temperature or in the microwave.

The most suitable use for thawed anchovies is in cooking — pasta, stews, sofritos — where texture matters less because it will melt anyway. For eating directly or on toast, the result does not compensate for the effort.

Our recommendation from Bacalalo: buy in a format and quantity that you will consume in a few days. A 50-gram can for one or two people, two cans for a family. Quality Cantabrian anchovies deserve to be consumed at their optimal moment, not taken from the freezer.

The Most Common Mistakes That Ruin Anchovies

In 35 years at Mercat del Ninot, we have seen all possible mistakes. These are the most frequent and those that have the most impact on product quality:

Mistake 1: Leaving the can open in the refrigerator without sealing. The most common mistake. Refrigerator air is dry and cold, which accelerates dehydration and oil oxidation. An open can without proper sealing in the refrigerator can ruin the product in less than 24 hours. Always cover before storing.

Mistake 2: Using plastic containers. Plastic absorbs odors and can transfer flavors to the oil over time. It is also micro-permeable to oxygen. Glass is always superior for storing anchovies.

Mistake 3: Handling with wet or dirty cutlery. Moisture is the enemy of preserved oil. Always use a dry, clean fork when handling the fillets. Cutlery with traces of water or other food can contaminate the oil and drastically reduce storage time.

Mistake 4: Storing at room temperature. An open anchovy left out of the refrigerator at room temperature in summer (25 degrees or more) can spoil in a few hours. Open anchovies always go in the refrigerator, without exception, except for the minutes before serving them.

Mistake 5: Not covering completely with oil. The oil acts as a physical barrier between the fillet and the air. A fillet that protrudes 2 millimeters above the oil level will oxidize and dehydrate in that area even if the rest of the fillet is perfectly preserved. Always oil above the last fillet.

Mistake 6: Storing leftover oil in the empty original can. If you have consumed all the fillets and want to save the oil to use as dressing, do not leave it in the open metal can. Transfer it to a small, closed glass jar. Oxidized metal can quickly alter the taste of the oil.

Mistake 7: Mixing with other products in the same container. Anchovies have an intense aroma and can transfer it to other foods and vice versa. Always store in its own, closed container, without mixing with other products.

Frequently Asked Questions about Storing Opened Anchovies

How long do opened anchovies last in the refrigerator?

With the correct method — airtight glass container, completely covered in extra virgin olive oil, refrigerator at 4 degrees — between 5 and 7 days with optimal quality. The absolute maximum is 10 days, after which the texture and flavor begin to degrade noticeably, although the product is not dangerous.

Is the oil in the can enough to preserve them, or do I need to add more?

It depends on how many fillets are left in the can. If you have consumed half or more of the fillets, it is likely that the oil level will not be enough to cover the remaining ones when transferring them to a smaller container. Always top up with extra virgin olive oil until all the fillets are completely submerged.

Can I store anchovies in sunflower oil if I don't have olive oil?

Technically yes, but it is not recommended. Sunflower oil has a neutral taste that adds nothing and a fatty acid structure different from olive oil, with a greater tendency to oxidation. Extra virgin olive oil is part of the anchovy's taste experience — sunflower oil impoverishes it. If you don't have olive oil on hand, use the minimum amount of oil possible (enough to cover) and consume it as soon as possible.

Do unopened canned anchovies need refrigeration?

No. An unopened preserve is stable at room temperature as long as it is stored in a cool, dark place without sudden temperature changes. Neither refrigerator nor freezer. Only once opened does the product require refrigeration.

Can you tell if anchovies are in bad condition before tasting them?

Yes. Smell is the most reliable indicator. Bad anchovies smell unmistakably of rancid oil or spoiled fish — there is no possible confusion with the normal aroma, which, although intense, is pleasant and marine. Visually, a grayish or greenish color on the fillet is also an indication of deterioration.

How many days do anchovies last if I buy them already opened at a market?

If you buy them already opened — for example, taken from a barrel or a large preserve in a market or delicatessen — the clock has been running since the original container was opened. Ask the seller when it was opened. Under correct store conditions, they are usually in good condition for up to 3-4 days after being served. At home, apply the glass container protocol and consume them within 2-3 days.

Which anchovies best resist preservation once opened?

Anchovies with higher fat content and longer curing resist the passage of time better. In general, large caliber (00) anchovies with a minimum of 12 months curing are more stable than small caliber and short-cured ones. The 00 Selection anchovies and the artisan anchovy fillets we sell at Bacalalo are in this category.