October 18, 2026, 12:09 pm | Read time: 4 minutes
A metallic taste in the mouth can be quite unpleasant, but it occasionally occurs when eating with metal utensils. myHOMEBOOK reveals exactly why this happens and what enhances the effect.
It’s a well-known phenomenon: Anyone who has eaten with metal utensils might have noticed a metallic taste that seems to transfer to the food. Acidic foods, drinks, or particularly aromatic foods can enhance the effect. But is it really a taste? In fact, the topic is more complex from a scientific perspective. The metallic taste is actually a combination of chemical reactions in the mouth (such as from saliva), smell perceptions, and metal ions.
Follow myHOMEBOOK on WhatsApp now
Taste or actual smell?
Sweet, sour, salty, bitter, and savory–these are the five tastes the human body can perceive. Metallic nuances don’t fit into any of these categories, which is why they’ve been a focus of research for years.
Studies actually suggest that metallic taste is a multimodal perception of the body, involving taste, smell, and sensations in the mouth.
The best example of this is iron. Almost everyone knows this phenomenon: The gum or cheek is slightly injured, and the bitter taste of blood spreads in the mouth. This often comes with a smell perception and an indefinable feeling. Blood contains red blood cells, where the iron-containing protein hemoglobin is responsible for oxygen transport. In experiments by the Institute of Food Science at Cornell University in Ithaca, U.S., participants reported experiencing a metallic sensation when consuming iron salts. Only when the test subjects held their noses did the sensation noticeably decrease.
Also interesting: Tricks to prevent flash rust on cutlery
The role of saliva
Human saliva plays a significant role in the multimodal perception of metallic nuances. While saliva is mostly water, it also contains proteins, lipids, and electrolytes that create a chemically active environment in the mouth. When certain metal ions meet these components, chemical reactions can occur. In a study by Pinar Omür-Özbek and colleagues in 2012, this mechanism in the mouth was examined. After the intake of iron and copper solutions, the oxidation of fats (lipids) in saliva increased significantly. Additionally, odor-active aldehydes were formed during this process, which could then be perceived through the nose.
It can be assumed that part of what we perceive as a metallic taste arises from retronasal smell, where molecules travel from the throat to the nose and olfactory mucosa. The brain integrates taste, smell, and oral signals into a unified perception.
Significant impact on taste receptors
Retronasal smell is an important part of the metallic taste. Further studies, however, showed that metal ions can also directly interact with taste receptors in the mouth. A 2019 study focused on the human bitter receptor TAS2R7. Cell experiments revealed that the receptor responds to divalent and trivalent metal ions, including zinc, calcium, magnesium, copper, and others. This can lead to various taste sensations.
It’s important to distinguish between metal ions in a solution and solid metal objects like cutlery. The aforementioned studies were all conducted with solutions of metal salts. Solid metals, on the other hand, release far fewer metal ions.
Can You Eat Acorns?
Copper Tape Can Effectively Repel Snails in the Garden
What role does the quality of cutlery play?
Although much weaker, metal cutlery can indeed influence the perception of food. The alloy plays a particularly important role.
In an experiment at Oxford University, participants had to taste creams of different flavors from various spoons. Spoons with alloys of gold, copper, zinc, and stainless steel were used. The result was surprising. The creams on the copper and zinc spoons were perceived as much more metallic than those on stainless steel or gold spoons. Cutlery is therefore not completely neutral in sensory terms.
Interestingly, copper and zinc also significantly enhanced the taste of the food samples. Creams that were already bitter tasted even more bitter with these two spoons. The interaction between material, food, and mouth environment can also make a difference, as the studies confirmed.
However, the study could not prove that inferior cutlery inevitably causes a metallic taste in everyday life.
Also interesting: What are the hole and edge on cooking spoons for?
What impact does dish soap have?
A metallic taste is often noticed, especially after washing cutlery. When this happens, not only the material but also residues from cleaning agents may be involved.
Rinse aid, in particular, can leave residues (such as alcohol ethoxylates) on dishes and cutlery in the dishwasher, as a study has shown. These residues may also cause a chemical or bitter aftertaste, which can be mistaken for the metallic taste of cutlery. However, the study could not prove that rinse aid residues trigger the typical metallic taste.