External contamination in a winery

Background:

An American winery asked LAAE to identify a weird odor that was spoiling thousands of bottles of its wine.

Strategy:

The lab used instrumental analysis techniques combined with the human nose (olfactometry) to find the molecule causing the off-flavor. Mass spectrometry analysis was then carried out to identify and quantify its presence in the wine.

Results:

A molecule with a characteristic onion odor was found in levels of parts per trillion in the contaminated wines. This wine had been elaborated with grapes cultivated near an onion processing company.

The lab was able to prove that the molecule was causing the off-flavor and that without doubt it was coming from the onions. The grapes near the onion company were storing the molecule in the form of an odorless precursor that was later released by the yeasts.

The results from the lab were presented as legal evidence in the subsequent lawsuit presented by the winery against the onion company.

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