Do natural wines differ from conventionally-produced wines?

Abstract

AIM: In recent years, consumer awareness for consuming healthy and environmental sustainability products has considerably increased [1]. In an ever-changing and highly competitive environment such as the wine sector, production of wines without sulfites, or biodynamic, organic or vegan wines, has experienced an important increase to meet the new needs of consumers [2,3]. Beyond these categories of regulated products, a new concept has emerged: natural wines (NW), for which there is not an established definition or legal regulation. Rather, producers have a personal idea of naturalness under the premise of applying minimal intervention from grape to wine production [4]. In this context, it is hypothesized that self-defined natural wines are different from conventional wines (CW) in their sensory and chemical profile. The predicament of natural wine is based on anecdotic declarations and assumes that minimal intervention guarantees the production of wines with organoleptic properties able to express the “terroir” and thus promote wine diversity, plurality and sensory typicity against the risk of standardization of CW. In addition, we want to test the hypothesis that NW are healthier than conventional by evaluating toxic-related metabolites.

METHODS: Twenty-eight commercial Spanish white wines were studied. Half were NW (i.e., winemakers declare to follow minimal intervention during grape and wine production) and half were conventional wines (CW). Pairs of NW-CW sharing variety and region of production were selected. They were submitted to sensory analysis following free sorting task and chemical characterization for conventional oenological parameters, histamines, ochratoxin A, ethyl carbamate and metals. RESULTS: NW present significantly higher pH levels, volatile acidity, color intensity, turbidity and higher contents of the histamine putrescine than CW, while lower levels of malic acid and sulfites were observed in NW. No significant differences were found for the levels of heavy metals and the rest of chemicals evaluated.Concerning sensory properties, while a higher proportion of NW than CW presented winemaking-related defaults, NW with positive fruity notes could also be identified.

CONCLUSIONS:

This work could partly confirm the main hypothesis by showing certain significant sensory and chemical differences between NW and CW. It appears necessary to carry out similar studies with a wider number of wines to achieve deeper knowledge in this field.