Grape varieties resistant to cryptogamic diseases are recognized as being innovative in reducing the use of viticulture inputs (see, for example Merdinoglu et al., 2009). A great deal of debate at the agronomic level has focused on the most effective ways to sustain this resistance (e.g. Bouquet, 1980; Delmas et al., 2016; Delmotte et al., 2014) and on the qualitative improvement in the produce from these varieties with a view to marketing the resulting wines (Salmon et al., 2017). In economic terms, analyses have focused on the expectations of producers (Lybbert and Gubler, 2008; Lybbert et al., 2012) and on the reduction of costs linked with the use of these innovations (Binzen et al., 2014). However, to our knowledge, no work has been done on consumers’ acceptance of wines from resistant varieties. The main reason is that, as for many innovative products, consumer data does not yet cover a sufficiently long period and also that, particularly in the wine sector, it is always difficult to understand the real trade-offs consumers make between, on the one hand, purely qualitative aspects, intrinsic to the product, and on the other hand any extrinsic effects linked with the label and the information available to consumers on production methods (provenance, certifications, claims, etc.), especially when they relate to environmental performance.

This article presents a methodology for evaluating consumers’ expectations and trade-offs in the context of experimental economics. The aim is to discover consumers’ willingness to pay (WTP) (generally for a bottle of wine with different information configurations) in a controlled laboratory experiment (i.e. with no social interactions) and guaranteeing the credibility of the disclosures of willingness to pay using disclosure incentive methods (see, for example, Lusk and Shogren, 2007 for an overview of these methods). The general questions that we are asking are as follows:

What is a consumer’s willingness to pay for a wine from a resistant grape variety, compared with their willingness to pay for other conventional wines, from the same production region and at the same price level?

What effect does information about environmental and health performances have on willingness to pay for wines from resistant varieties and on consumers’ quality-price trade-offs?

Initial responses to these questions are provided in this article with the results from an experimental market held in Paris in June 2017. As part of a specific study on white wines from the Languedoc winegrowing region of France, we selected a wine from the Bouquet 3159 grape variety, produced at the Institut National de la Recherche Agronomique¹ (INRA). The 2016 vintage wine was compared with two types of conventional wine: one standard conventional wine from the same wine-producing estate, also marketed by INRA, and a ‘premium’ wine from another estate in the same production region, the Languedoc, but of a higher quality and price. We also selected an organic regional wine for this experiment to better position the ‘resistant variety’ option in relation to an alternative production method which is also committed to pesticide reduction, but which is nevertheless more traditional for consumers. The environmental and health performances of the production methods of the different wines were quantified using the treatment frequency indicator (TFI) and chemical and biological pesticide residue analyses.

Our results showed that, at a purely sensory level, consumers had difficulty in accepting wine from resistant varieties. The amount they were willing to pay is indeed significantly less than for traditional quality wines. However, information on the environmental and health performances resulted in a strong improvement in the market position of the wine from the resistant variety. By using actual selling prices and comparing them with consumers’ willingness to pay, we then estimated the losses of market share for the conventional wines. We noted that these losses were considerably less for the quality wines, despite their poor environmental performance (TFI greater than 10) and health performance (presence of synthetic pesticide residues in the conventional wines and copper residue in the organic wine). Lessons for public policy concern consumer expectations in terms of environmental and health issues as today these are an integral part of wine quality.

There is currently a large amount of literature available on wine consumers’ expectations in terms of environmental and health improvements in production methods. As Schäufele and Hamm (2017) recently highlighted in a review of this literature, these considerations regarding sustainable development are certainly becoming increasingly important for European and North American consumers and are gradually being reflected in their purchases (see also Delmas and Grant, 2014; Forbes et al., 2009; Pomarici and Vecchio, 2014). Recently, a large number of these studies have focused on organic wines to evaluate the ‘premium’ achieved from this certification when associated with environmental labeling (e.g. Brugarolas et al., 2005; Schäufele and Hamm, 2018). However, several authors have shown how difficult it is to gain a clear understanding of the true motivation of organic wine consumers who often interpret this certification as a sign of quality in general (e.g. Pagliarini et al., 2013). Authors have also shown how difficult it is to measure consumers’ true trade-offs between, on the one hand, the attributes of sustainable development and on the other, the organoleptic evaluation, which often predominates (Loureiro, 2003; Schmit et al., 2013). It goes without saying that these results remain dependent on market specificities and consumer characteristics according to age, gender or income (e.g. Sellers-Rubio and Nicolau-Gonzalbez, 2016; Thomas and Pickering, 2005) and a large number of empirical studies will be needed to identify, if possible, some more general results.

More recently, Schäufele and Hamm (2018) focused on the very great difference between consumers’ intentions and expectations and their real market purchases, as these often do not match their declared intentions and expectations (the famous “attitude-behavior gap”). Incentive methods that we find in the experimental economics literature can partially resolve this phenomenon by avoiding the ‘social desirability bias’ and taking consumers’ income constraints into account (for applications to wine see, for example, Combris et al., 2009; Vecchio, 2013). The laboratory experiment that we carried out is one of these experimental economics methodologies and it enables us to test innovative wines that have no historic consumption and purchase data. We chose to use a method involving direct disclosure of consumers’ willingness to pay (Combris et al., 2015), where consumers fixed minimum purchase prices, after comparing products that had been offered to them for sale. The wine that is sold to them is the one that maximizes their surplus (difference between WTP and sale prices, which is drawn at random, along the same lines as in the original method suggested by Becker et al., 1964).

Here we describe our experimental protocol which starts with wine selection and the measurement of sustainable development indicators, in order to better control the effect of the information available to consumers when they disclose their willingness to pay.

The wines that we submitted to consumers for the comparison test were selected as follows. First, we selected a wine produced from a resistant variety, available for sale and optimized in terms of quality (monogenic variety partially resistant to mildew and totally resistant to powdery mildew). In France, the Institut National de la Recherche Agronomique (INRA) carries out this type of activity at its Pech Rouge experimental unit. Concentrating on available wines from the 2016 vintage, a jury of 10 professional tasters gathered at INRA Pech Rouge in December 2016 for a blind tasting and finally suggested focusing solely on the white wines from this winery, selecting the wine which was the best quality for the resistant varieties: this was a wine produced from the Bouquet 3159 grape variety, aromatic, but whose features did not contrast too strongly with the traditional Languedoc wines. A second white wine was selected from the same establishment, INRA Pech Rouge, and the same vintage, 2016, but this time produced from varieties authorized under the ‘Aude’ Protected Geographic Indication scheme for which this wine is eligible. Although the grape varieties were different, this ‘standard conventional’ wine from the domain could be considered, in the opinion of the tasting jury, as an adequate substitute for the resistant variety wine (as the differences in their characters were not too great). To complete the test we took the decision to select what we called a ‘premium conventional’ wine from the same winegrowing region, the Languedoc (but this time a Protected Designation of Origin ‘Languedoc’ wine), from the same vintage, 2016, and which could ideally be a higher quality substitute, with a high price level, while still remaining below the psychological price threshold of €10 (as we see below in Table 1, the ex-cellar price of this premium conventional wine at the time of the experiment was €8.90, while the resistant variety wine cost €6 and the ‘standard conventional’ wine sold for €4.70 at the property).

Apart from the organoleptic aspects, the second criterion that determined our selection was the performance of the wines in terms of reducing the use of phytosanitary products in the vineyard. This was why we also decided to select a wine with organic certification, a designation well known to consumers. Organic certification can indeed add value for what it represents in terms of the reduction in the use of pesticides, although for producers it remains expensive, and in certain cases carries risks.² This organic wine that we added to the experiment, still from the 2016 vintage and the same winegrowing region of the Languedoc, is equivalent in price to the premium conventional wine (€8 per bottle ex-cellar). We shall see in the sections that follow that environmental and health performances can also be considered as relatively equivalent to that of the resistant variety wine, but in contrast, the detection of copper residues in this wine (since the use of copper is acceptable to avoid the growth of mildew) may lead to negative reactions regarding willingness to pay.

Measuring the environmental impacts of agriculture is a complex task, which is addressed in the literature through different families of methodological approaches: risk mapping, lifecycle analyses, development of agro-environmental indicators (Payraudeau and van der Werf, 2005). Within this family of agro-environmental indicators we distinguish state indicators, measuring environmental quality (downstream approach) and pressure indicators, based on agricultural practices, either measured or modeled (upstream approach) (Pingault et al., 2009). These pressure indicators can cover different types and aspects of agricultural activity: crop rotation (and its impacts on biodiversity), use of irrigation, use of fertilizers and soil improvers and of course the use of pesticides.

Concerning measurement of the use of pesticides, Falconer (2002) reported the lack of widely recognized environmental indicators available to producers and especially to regulators in order to move towards more sustainable technical routes; designing and evaluating public policies that favor these indicators. There appears to be no indicator that successfully takes into account all the different parameters that have to be considered when judging the environmental impact of pesticide use: the doses used, the relative speeds of degradation of the products considered, their relative dispersion in the air, water, soil compartments and finally, their relative and combined toxicities (“cocktail effects” linked with interactions between the different active ingredients that are still not well understood) in relation to different living species (Bockstaller et al., 1997; Levitan et al., 1995; van der Werf, 1996).

The most commonly used indicators in this field deal first and foremost with the first of these factors: they are built around the comptability of doses applied by farmers. This is notably the case for the Treatment Frequency Indicator (TFI) for phytosanitary products, defined as the number of reference doses³ applied on a cultivated plot during one growing season (Pingault et al., 2009). This indicator is based on Danish research (Gravesen, 2003) which was later adapted in France by INRA and IRSTEA (Aubertot et al., 2005; Champeaux, 2006).

T F I = d o s e   a p p l i e d r e f e r e n c e   d o s e × s u r f a c e   a r e a   t r e a t e d t o t a l   s u r f a c e   a r e a

The TFI does not relate to the number of treatments carried out, but more precisely to the number of reference doses applied to a plot. Unlike the simple number of phytosanitary treatments, this index has the advantage of taking into account both the doses actually applied and the surface area actually treated. Finally, since this index corresponds to a ratio expressed in units, doses of different products can be added together and grouped into categories: “TFI fungicides”, “TFI herbicides”, etc. This is a useful distinction in order to understand the relative importance and the different uses of these pesticides for different crops and in different regions.

The difficulty of this kind of synthetic index, based on a simple principle of adding quantities of pesticides, still remains in the fact that the different products used are given equal consideration, whatever their degree of toxicity or persistence in the environment (Barnard et al., 1997). In this respect, the TFI along with other non-weighted indicators of pesticide profiles are imperfect environmental and health indicators.⁴ Nevertheless, their use has become extremely widespread, especially in France, with support from public authorities systematizing their use and taking readings through field surveys.⁵ Despite its imperfections, this indicator is becoming the measure of effectiveness of French public policies, in the sense that a drop in TFIs must be able to objectivize an environmental improvement, and thus the arbitration process for product recommended doses becomes crucially important.

While the TFI concerns cultivation practices, the original feature of our own process is to attribute it to a finished product. This has been made possible by using the treatment record books for the plots on which the wines for the experiment were produced. For the sake of simplification, in the following we shall say that a wine has a TFI of X to denote the fact that it is produced from plots of which the average of their TFIs, weighted for the composition of the blend, is X.⁶ More precisely, to get as close as possible to an environmental indicator, we shall consider TFIs excluding biocontrol products. Ultimately, we obtain the environmental performances shown in Table 1: the wine from the resistant variety had a TFI excluding biocontrol products of 2, for the ‘standard conventional’ wine it was 16.9, for the ‘premium conventional’ wine 12.7, and for the organic wine 2. Thus the organic wine had the same environmental performance as the resistant variety,⁷ making comparison easier for consumers.

The question of analyzing for the presence of pesticide residues in food products has long been a subject for discussion in the scientific literature. In the case of wine, analyses are more recent and follow on from the increasing awareness on the part of the media (and hence of consumers) of this question of using pesticides in wine production.⁸ However, evaluation techniques are constantly evolving and we often observe considerable variation in results, depending on the analytical laboratory used and the evolution of the wines. For this reason, we used two different laboratories to perform these analyses:

- Unité Œnologie de l’Institut des Sciences de la Vigne et du Vin (ISVV), Université de Bordeaux, France.

- El Instituto de Investigación y Análisis Alimentario (IIAA) de la Universidad de Santiago de Compostela (USC), Spain.

The ISVV laboratory tested for the presence of 190 active substances and quantified the compounds detected. The IIAA quantified the pesticide residues in the four wine samples from a predefined list of 33 compounds. The IIAA also tested the wines for the presence of a dithiocarbamate metabolite, ETU (ethylene thiourea). However, in order to link practices in the vineyard and the compounds found in the wine, we decided to focus the analytical search on residues, mainly on the active ingredients applied to the plot. In addition, the information provided for consumers concerned only pesticide residues applied to the vines.

Note that at this stage, maximum residue levels (MRL), intended to guarantee a certain level of food safety in products for European consumers, do not yet exist for wine (see Appendix VI of Regulation 396/2005), only for wine grapes (in mg/kg). The results of our analyses cannot therefore be compared with regulatory limits specific to wine. In the absence of MRLs to provide a comparative reference value, we decided to provide consumers with information in terms of the number of residues present and their quantity. The weak signal for the ETU metabolite in the case of ‘premium conventional’ wine (the only wine to present with this metabolite) was not considered as it was below the limit of quantification (LOQ). Finally, copper was the only pesticide quoted. This prominence given to the name of the molecule was done deliberately, in order to assess whether the organic wine could indeed be penalized by the presence of copper (main stumbling block of this certification). No residue was detected for the wine produced from resistant variety. However, the ‘standard conventional’ and ‘premium conventional’ wines reported respectively six and three pesticide residues which were actually applied at the vineyard.

Table

titre du tableau
Wines	‘Resistant variety’ wine	‘Standard conventional’ wine	‘Premium conventional’ wine	‘Organic’  wine
Code	309	417	575	231
Organoleptic quality	Standard	Standard	Superior	Standard
TFI	2	16.9	12.7	2
(excluding biocontrol products)
Grape varieties	100% resistant grape variety Bouquet 3159	45% Sauvignon,	50% Roussanne,	100% Viognier
		31% Viognier,	30% Grenache Blanc,
		17% Chenin,	20% Viognier
		7% Arriloba
Phytosanitary product residues	No residue of applied pesticide	Residues of 6 applied pesticides	Residues of 3 applied pesticides	Applied copper residues
Sale price (ex-cellar)	€6/bottle	€4.70/bottle	€8.90/bottle	€8/bottle

Consumer selection was carried out by a specialist recruitment agency. The consumers were all recruited in the Paris region where the experimental laboratory was located. A certain number of filters were applied to achieve a balanced population:

The panel had to be evenly distributed between men and women.

The panel had to be evenly distributed in terms of age, and only target adults.

The panel had to be representative of all socio-professional categories, limiting the proportion of students to a maximum of 10%.

100% of consumers had to buy wine at least once a week.

100% of those recruited had to be consumers of dry white wine at least twice a month.

No person on the panel should be involved in the winegrowing sector.

Consumers were compensated by the recruitment company, and this payment was completely disconnected from our experiment. In the end, and taking these recruitment filters into account, the panel consisted of 163 consumers, 82 women and 81 men, with an average age of 50.8 years (standard deviation 11.8). The minimum age was 22 years and the maximum 81 years. There were 22 consumers in the 20-35 age bracket, 73 in the 36-55 age bracket, and 68 were aged over 56. The average age of the men was 51.9 years and of the women 49.9 years. Consumers were put into three groups according to their monthly income. The first group contained 60 consumers with earnings of less than €2000 per month. The second group contained 73 consumers with earnings of between €2000 and €4000 per month. Finally, the last group contained 30 consumers with earnings higher than €4000 per month. On average, the women on the panel earned more than the men.

The experiment took place in June 2017 in a sensory analysis room⁹ in the Paris region, kept at an ambient temperature, with nine sessions held (each session included between 17 and 20 consumers) all taking place in the same week (comparable external conditions for the consumers). It should be noted that each consumer was paid €30 by the recruitment company, for their participation in this experiment (this payment was quite separate from the sale of wines during the experiment). Each consumer had received a letter at their home explaining the experimental conditions and the selling principle to be applied, with an explanation of the notion of willingness to pay and the proposed disclosure mechanism. This mechanism was explained once again at the session, using examples to ensure that they clearly understood it and the incentive to disclose their WTP, taking into account the level of information available about the products on sale. Before starting the experiment, it was explained to the consumers that the study was interested in their personal opinion, the aim being to collect at each stage their sensory and economic trade-offs. We also made it clear that an absolute refusal to buy a wine at one time or another during the experiment would result in a WTP of zero.

The experimental protocol consisted in a comparison of the four wines, as we gradually provided more and more information on them (on this point, see Fuentes Espinoza, 2016): the consumers were asked to evaluate the wines at several different stages and at each stage we recorded the new WTPs for each wine, according to the information available on these wines at this stage of the experiment. Each step therefore corresponded to additional information, which could lead each consumer to re-evaluate their WTP if they so wished. As is customary in the field of experimental economics, we assured the consumers that none of the information provided was untrue and it could be verified at the end of the experiment.

At the start, all the consumers had a single piece of information, common to all four wines, on the fact that the wines were all from the Languedoc region of production and were a 2016 vintage. The purpose of this information was to provide consumers with a minimum framework for evaluation and cognitive structuring. Just before the start of the experiment, each wine was served in a clear tasting glass, with a standard quantity of 20 ml per glass, and so that at the time of the first and only tasting (step 1, see below) each wine was at a temperature close to 12°C. The wines were coded and arranged in random order at each tasting station, meeting the rules for the Latin square design.

To keep the economic incentive intact at each step and on each declaration made, participants were only informed at the beginning of the session that the final sale would relate to one of the steps in the experiment. With no more information than this, any one of the steps could therefore apparently be the one. An envelope, visible to everyone, was pinned to the wall before the participants came into the room. They were told at the beginning of the session that this envelope would be opened just before the sale and that it contained the number of the step to which the sale would relate. The incentive and the unveiling of the conditions of the sale were therefore made acceptable and concrete. Note that this principle is similar to the ex ante sale price fixing used in the Prince method developed by Johnson et al. (2015) to measure preferences. Finally, note that the consumers were not told the number of steps in the experiment thus avoiding the creation of expectations and strategic behavior between steps. As explained to the consumers at length during the first half-hour of the experiment, this selling stage guaranteed that at every step in the experiment everyone had to provide his or her actual WTP for each wine, taking into account the information available during the step under consideration and in a framework of comparison between the four wines offered.

The steps in the evaluation process were as follows:

Step 1 (Organoleptic evaluation) : Each consumer carried out an organoleptic evaluation of each of the four wines (global evaluation considering the visual, olfactory and taste characteristics). Each consumer was asked to respect the individual tasting order proposed at each station (glasses arranged in a line, from left to right, with a different order at each station). The consumers then gave their evaluation for each wine giving a score on a non-calibrated hedonic scale of 0 to 10,¹⁰ then their willingness to pay for a bottle of each wine.

Step 2 (TFI information) : This step began with a short explanation of the use of phytosanitary products to protect crops and harvests, and their potential impact on the environment (soils, water, air) and man (residents, wine producers). After defining and explaining the notion of TFI (excluding biocontrol products), we gave the consumers the level for this indicator achieved for each wine (values shown in Table 1).

At the end of this step, consumers gave a new WTP for each wine (which may or may not be different from that given in step 1).

Step 3 (Information on type of viticulture) : During this step, consumers were given definitions for the following terms:

- “conventional wine”, involving the use of synthetic phytosanitary products and those of natural origin; compliant with European regulations.

- “organic wine”, involving the use of phytosanitary products of natural origin only.¹¹

- “resistant variety wine”, produced from a varietal innovation: non-traditional variety in the production region, but resistant to grapevine diseases, and allowing a very reduced use of phytosanitary products.

For each of the four wines in the experiment, we provided information on how these definitions related to these wines. With this additional information, each consumer then re-evaluated their different WTPs, if they so wished.

Step 4 (Information on pesticide residues): During this step, we gave the consumers information on the presence or absence of several pesticide residues applied to the plot, as shown in Table 1. In the case of the organic wine, we told consumers that the pesticide found in limited quantities was copper, which is permitted in organic farming. In the light of this additional information, the consumers then revised their WTPs for each wine if they wished, as in the previous step.

Before the final step, consisting of the sale, two intermediate steps were introduced, although these results are not discussed here. During these two steps, consumers considered only two of the original four wines (organic wine and resistant variety), again giving their WTP for each bottle. First, they again gave two new series of WTPs for the organic wine and the resistant variety with no more information than at step 4. Next, we showed them the labels and back labels of these two wines then asked for new WTPs. In practical terms, these two steps made it possible to carry out the promised sale at the end of the protocol, a necessary step if a real economic incentive is to be created, while at the same time saving on the costs of the experiment. The sale in fact concerned one of these two wines (from the step number written in the envelope pinned to the wall), and thus the experimental team only needed to have these two wines in stock.

Final step (Sale): At this point, the envelope pinned to the wall was opened. The intermediate step was revealed and the sale took place in the session for a certain number of consumers chosen at random from the room. The sale prices of each of the four wines were also drawn at random from a box of prices (the consumers did not know beforehand that the price distribution would be done in this way) and were binding on each consumer. Next, each consumer selected for the sale bought the wine that maximized his surplus (difference between the WTP declared at the intermediate step and the wine’s sale price), assuming that at least one surplus is positive.¹²

Thus for each step in the evaluation process, consumers had to provide a (new) WTP for each of the four wines. At the first step we asked them for a simple hedonic score so that they would focus on the intrinsic qualities of the products by giving their general appreciation regardless of any economic consideration in purchasing these wines (subsequently, we would of course check that the WTP given in step 1 was an increasing function of this hedonic score). The following steps only added information about each wine, regarding production methods and the results of the indicators on environmental and health performance.

We shall return in the final discussion to the relevance of testing this type of information when it is not subject to labeling regulations. We shall simply note at this stage that while the process we used of providing information in increasing amounts (and hence, not independently) is partly determined by operational considerations of the experiment, it nevertheless fully justifies research into the effect of providing information contextualized by a prior organoleptic evaluation and knowledge of the region of production and the vintage.¹³

The following figures give an overview, based on the averages of the hedonic scores and willingness to pay, of the ranking of the wines by the consumers, taking into account the standard deviations in our population. Figure 1 shows the average hedonic scores awarded to the four wines in step 1.

Table

Two products share the same letter (e.g. “A”) if and only if they have not been valued significantly differently by all of the group (ANOVA).