A little smokey flavor may enhance the character of superb wine, but how much is too much? “I’m sure I’ve met bottles of wine and thought, ‘Wow, this is an ashtray.’ How did it get this far?'” asks Eleni Papadakis, a winery consultant who judges regional contests.
According to Papadakis, the impact of recent wildfires on grapes may be tasted in wines from Oregon to California and throughout the world — yet determining which vineyards have been harmed by smoke taint can be difficult and costly.
“And do you simply discard an entire vintage for an entire region?” she asks, noting that vintners might spend thousands of dollars testing to detect damage.
Enter Phil Crews, a winemaker and chemistry professor at UC Santa Cruz. Crews initially became aware of the smoke damage issue during the Mendocino Complex fire in 2018 and began researching improved procedures for determining which grapes carried so-called “smoke taint.”
The shame can occasionally be concealed when smokey substances known as phenols establish complicated molecular bonds with sugar molecules in the grapes. However, they can be released later in the fermentation process or even when the compounds come into touch with a wine drinker’s mouth.
“This combination will be cleaved by the enzymes in your saliva and bacteria in your mouth, releasing the volatile, foul-smelling phenols. That is when they are palatable,” Crews explains.
To better understand the process and the shame it causes, professor Crews built on research conducted in Australia, where wildfires ravaged grape harvests as well.
The critical step is to look for smoke-derived chemicals that may be utilized as biomarkers.
Modern methods like ultra-high-performance liquid chromatography, UHPLC, and quantitative mass spectrometry can then aid in identifying the constituents, even if they do not provide the full smokey flavor in their current state.
“That was a method we proposed, separating chemicals. And it is these complexes that you measure and view using mass spectrometry; chromatography does the separation, while mass spectrometry performs the imaging,” Crews explains.
The expectation is that more precise testing will save winemakers millions of dollars each year by identifying and preserving just the afflicted grapes.
“And maybe make better judgments and rescue more,” Papadakis adds. All of this in an industry known for its razor-thin profit margins and picky consumers.
According to the researchers, the study is based on an investigation of over 200 grape and wine samples from 21 grape-growing areas in California and Oregon.