The answer to why fish smells while cooking is that certain compounds in the fish's flesh break down over time and with heat into volatile, sharp-smelling substances. In particular, a compound called trimethylamine increases as the fish loses its freshness, and it is released into the air during cooking, creating the characteristic fishy smell.
Certain compounds naturally present in the flesh of saltwater fish are slowly broken down by bacteria and enzymes after the fish is caught. The volatile amines released as a result of this breakdown give off a stronger smell the longer the fish has been sitting. Since heat speeds up the release of these volatile substances into the air, the smell becomes most noticeable during cooking. That's why a very fresh fish gives off only a mild sea smell when cooked, while a fish that has lost its freshness releases a much sharper and more unpleasant odor.
Why Does Fish Smell While Cooking, and How Can the Smell Be Reduced?
Although it is not possible to eliminate the smell of fish entirely, it is possible to noticeably reduce it by choosing fresh fish and preparing it properly.
- Fresh fish should be preferred whenever possible, choosing ones with bright eyes and firm flesh.
- Drizzling lemon juice or vinegar over the fish before cooking neutralizes volatile compounds and reduces the smell.
- The fish can be soaked briefly in milk or lemon water, then patted dry before cooking.
- The kitchen should be well ventilated during cooking, with the range hood running.
- Utensils and containers used for cooking fish should be washed immediately with warm lemon water.
What Are Common Mistakes Made When Preparing Fish?
Certain mistakes made when preparing fish make the smell much stronger than it needs to be.
- Choosing fish that has lost its freshness causes a much sharper smell when cooked.
- Leaving fish unrefrigerated for a long time without proper cooling increases odor-causing compounds.
- Skipping treatment with an acidic liquid (lemon, vinegar) before cooking misses the opportunity to reduce the smell.
- Cooking in a closed, unventilated kitchen causes the smell to permeate the space.
Why Does Fresh Fish Smell Less?
Since the volatile compounds that cause odor have not yet formed to a great extent in fresh fish, only a mild sea smell is noticeable when cooking it. As the fish sits longer, these compounds increase and the smell gradually becomes sharper. For this reason, assessing the fish's freshness is decisive for both flavor and smell; bright, clear eyes, firm flesh, and a mild, non-sharp sea smell are the most practical indicators of freshness.
Why Do Lemon and Vinegar Reduce Fish Smell?
The volatile amines that cause fish odor are alkaline in nature; acidic liquids like lemon juice or vinegar react with these compounds, making them less volatile and reducing their release into the air. This is why rubbing fish with lemon before cooking or squeezing lemon over it when serving both lightens the smell and adds freshness to the flavor. By the same logic, washing containers used for cooking fish with lemon water also reduces the lingering smell in the kitchen.
In summary, the answer to why fish smells while cooking is that the compounds in its flesh turn into volatile, sharp-smelling substances over time and with heat. Choosing fresh fish, using lemon or vinegar before cooking, and ventilating the kitchen well noticeably reduce the smell. When these simple precautions are applied together, cooking fish becomes a much more comfortable kitchen experience.