As a lifelong canned tuna aficionado I know the pure joy of biting into a tender, flaky chunk of albacore bathed in rich olive oil. But other times I’ll crack open a can only to get hit with an unpleasant metallic tang that ruins the entire experience.
We’ve all been there – when tuna tastes more like biting into aluminum foil than a savory seafood treat. But what causes that inexplicable metal mouth? After polling fellow tuna lovers and doing some research, I uncovered the science behind the metallic fish phenomenon.
It’s Not Just in Your Head
You may wonder if the metallic taste is all in your imagination. After all, canned tuna is sealed in an actual metal container!
But several scientific studies have confirmed that metallic flavors can occur in canned fish and meats. Researchers found higher levels of iron and lipid oxidation in tuna samples with a metallic taste versus normal.
So rest assured, if your tuna tastes like metal, you’re not just psyching yourself out – there are real chemical processes creating that sensation.
Oxidation During Processing
Tuna begins to oxidize and deteriorate immediately after being caught. Proper handling during transportation and processing is key to maintaining quality.
Several factors during canning can cause metallic flavors:
- Excessive heat damages lipids and proteins
- Iron leaches from equipment into fish
- Oxygen reacts with fats
This oxidation produces a wide array of compounds, including aldehydes and ketones, that create “off” metallic tastes.
Storage Temperature and Duration
Canned tuna can keep for 2-5 years if stored properly, away from heat light and air. But over time, oxidation continues slowly within the can.
Tuna stored at higher temperatures for prolonged periods is particularly susceptible to increased metallic flavors. Try to keep canned tuna below 75°F if possible.
I asked a friend who stocks cans in her pantry for “emergencies” – sure enough, tuna stored for over a year started tasting metallic!
Light Exposure
We all know light can degrade food quality. But did you know it can specifically intensify metallic flavors in canned tuna?
Studies found tuna exposed to fluorescent light for just one week developed a significantly more metallic taste. Reaction products formed that increased iron and copper levels.
So keeping your canned tuna in a cool, dark place is ideal for avoiding metal mouth.
BPA Linings
Most canned tuna is lined with BPA plastic to prevent corrosion of the can itself. But BPA can leach into the fatty tuna, especially when stored in heat or agitated frequently.
Some scientists believe BPA may “activate” metals already present in tuna, enhancing the metallic taste. Look for BPA-free cans or pouches if possible.
Fishing and Processing
The way tuna is handled after catching also influences its likelihood of tasting metallic later on.
Best practices like prompt bleeding, icing, and minimal temperature fluctuations help reduce oxidation risks during processing. But not all companies follow strict protocols.
Seeking reputable brands like Wild Planet and American Tuna known for quality controls can help avoid metal mouth.
Which Type of Tuna is Most Prone?
From my survey, fans reported metallic tastes most often in:
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Chunk light tuna – Made from smaller, younger fish with less fat to mask metallic flavors
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Vegetable broth – The brine lacks the richness of oil that can offset metallic notes
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Store brands – More likely to cut corners during processing compared to major brands
Solid white albacore tuna in olive oil tends to avoid the metal mouth phenomenon. The higher fat content and milder flavor help mask metallic tastes.
Can Metals Hurt My Health?
Ingesting small amounts of metals like iron, zinc, and copper from foods is not harmful. But extremely elevated levels from heavy metal contamination could potentially impact health over time.
To be safe, avoid tuna that tastes strongly metallic. Also, don’t eat it every single day. The FDA recommends limiting light tuna intake to about two 4-oz cans per week.
How To Reduce Metallic Tastes
If you open up a can and detect even a hint of metal, there are a few tricks to mask the flavor:
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Mix with strongly flavored ingredients like mustard, lemon juice, pickles, or salsa
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Opt for well-chilled tuna since cold dulls metallic tastebuds
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Switch out metal fork and bowl for plastic, ceramic, or wood
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Sprinkle in fresh herbs and spices like dill, pepper, paprika, or garlic
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Up the fat content by adding avocado, mayo, or olive oil-based dressing
With some creativity, you can often salvage metallic tasting tuna. But if the flavor is overpowering, it’s probably safest to cut your losses and toss the can.
The Takeaway on Tinny Tuna
While not the most appetizing taste, a subtle metallic flavor likely won’t hurt you. But strong metal mouth can indicate lower quality or deteriorated tuna you’re better off not eating.
To minimize metallic canned tuna, opt for high-end brands, store properly in a cool, dark place, and use within a year or two of purchase. Seek out BPA-free options in olive oil rather than vegetable broth.
And if you do get unlucky with a metal mouthful, try masking the flavor with lemon, fat, or spices. But if the tang is too overpowering, don’t risk it – your best bet is to chuck the questionable can and try another!
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FAQ
Why does canned food taste like metal?
Is tuna metallic?
Why do I feel weird after eating canned tuna?
Why do things taste metallic?
Why does my mouth taste metallic when I eat fish?
For instance, fish and other seafood can sometimes contain high amounts of mercury, which can produce a metallic taste in your mouth after eating, per the Cleveland Clinic. Organ meats like liver and tripe are also rich in iron, according to the Cleveland Clinic, which can likewise cause a metallic taste when eaten in large doses.
Why does my food taste metallic when I eat?
If you take supplements with your meal, this could be the cause of the metallic taste in your mouth when eating. Indeed, minerals like zinc, chromium, copper, calcium and iron can all be the reason why you taste metal when you eat, especially if you’re taking these supplements in high doses, according to the Cleveland Clinic.
Why does meat taste like metal?
Substances in Meat If you’ve ever wondered why meat tastes like metal, certain substances may be to blame. For instance, fish and other seafood can sometimes contain high amounts of mercury, which can produce a metallic taste in your mouth after eating, per the Cleveland Clinic.
How do you know if canned tuna has gone bad?
The top ways to tell if your canned tuna has gone bad is to check the expiration date, see if the can is leaking, smell it to check for bad odors, see if it’s changed color, check the can for damages, and finally, taste it, which should be your last option if you’re suspicious.