Increases in the numbers of earwigs in European vineyards led scientists to study the impact of earwigs on wine.* Earwigs feed on insect pests of grapes, but can be harvested with grape clusters and contaminate them with their bodies or with feces deposited on the grapes. Do the earwigs affect the quality of wine?
The number matters. Only a few earwigs per kg of grapes has little perceptible effect. 10 or more earwigs per kg imparted a significant taste to the wine. As little as 0.6 kg of earwig feces per kg produce an off flavor variably described as “animal”, “reductive”, “vegetal”, “acidic”, “bitter” and “tannic”. The study suggests that high earwig densities in grape orchards can lower the quality of wine. European grape growers may alter some practices that reduce the numbers of earwigs, especially near harvest.
*P. Kehrli, J. Karp, J.-P. Burdet, P. Deneulin, E. Danthe, F. Lorenzini, C. Linder. 2015. Impact of processed earwigs and their faeces on the aroma and taste of ‘Chasselas’ and ‘Pinot Noir’ wines. Vitis 51: 87–93.