Wine myths
Petrol notes mean the Riesling has gone bad
“That kerosene smell means the Riesling is faulty or over the hill.”
It comes from TDN, a compound that develops as Riesling ages and is associated with sunlight exposure and warmth in the vineyard. Many drinkers value it; it is not a fault.
The full answer
The compound is 1,1,6-trimethyl-1,2-dihydronaphthalene, universally shortened to TDN. It forms in bottle from precursors laid down in the grape, and it accumulates with age.
Vineyard conditions bear on how much precursor is there in the first place. Higher sunlight exposure, water stress and warmth are associated with more; shaded fruit and cooler seasons with less.
It is not a spoilage compound and it is not produced by anything going wrong. A Riesling showing it is behaving exactly as an ageing Riesling behaves.
Preference genuinely divides. Many experienced Riesling drinkers regard it as a marker of maturity and seek it out; others dislike it; some regions and producers work to limit it. Divided preference is not the same as a fault, and WineHQ keeps the two apart.
At very high concentrations most tasters find it overwhelming, and some producers regard it as a defect in their own house style.
A biochemical or physical process that has been demonstrated experimentally and is not seriously contested — the sort of statement that appears in enology textbooks without hedging.
What would settle it: A controlled experiment failing to reproduce the process.
Sources
Sources consulted
- The Australian Wine Research Institute — AWRI
- Deutsches Weininstitut (German Wine Institute) — DWI
- The Oxford Companion to Wine — Oxford University Press