Corked wine can 'shut down' the nose
Scientists believe corked wine can taste awful because contaminants dampen the nose's ability to smell.
A chemical called TCA sometimes gets into a cork and leaves the wine smelling like a damp cloth or strips the drink of its flavour.
Researchers at Osaka University, Japan, say the effects may not be down to TCA's own unpleasant odour, but the way it suppresses the sense of smell.
They want to use the findings to develop ways of hiding bad smells.
TCA or "cork taint" can be a wine producer's nightmare. It can leave the wine reeking so badly it is destined for the sink or so bland it becomes a readily forgettable experience with customers unlikely to come back for more.
The team at Osaka University was investigating how TCA functions by analysing how the smell-centres of newts and people responded to the chemical.
End Quote Prof Hiroko Takeuchi Osaka University
Our findings here show that TCA suppresses activity of sensory cells,”
Prof Hiroko Takeuchi, from the university's Graduate School of Frontier Biosciences, told the BBC: "A major contaminant in corked wine is TCA.
"It has long been thought that TCA causes excitation of sensory cells to induce unpleasant sensation.
"However, our findings here show that TCA suppresses activity of sensory cells, we also speculate that this suppression may cause a musty smell that is a typical feature of corked wine."
Writing in Proceedings of the National Academy of Science, the researchers said dimming the nose's ability to pick out aromas in the air may lead to imaginary musty smells, which they called "pseudo-olfactory sensations".
Prof Takeuchi added that the findings may have implications beyond just corked wine.
"The present work shows that the reduction of quality found in foods and beverages is, at least in part, due to the generation of a suppressor, rather than the reduction of original flavour.
End Quote David Wrigley Wine and Spirit Education Trust
Not recognising a TCA fault has the potential to do a lot of damage to a brand”
"TCA can be generated in any processes of sterilisation, storage, aging and transportation. After this finding, all people concerning these processes will pay attention to their roles in order to improve the quality of products."
The group is also looking at using the mechanism to deliberately weaken the nose's sense of smell in products to hide bad odours.
David Wrigley, a master of wine and from the Wine and Spirit Education Trust, said: "One of the problems with TCA is it is very marked and really quite noticeable.
"It comes in degrees and there's a point at which the mustiness is negligible, but the wine is seemingly lifeless.
"Of course that's potentially hugely damaging as not recognising a TCA fault has the potential to do a lot of damage to a brand."