We analysed the impact of operation variability on the composition of pear spirits obtained with a Charentais alembic and a packed distillation column. Lack of reproducibility significantly affected the spirits' compositions, with batch distillation columns more difficult to operate reproducibly vs. traditional alembics. The composition of column distilled spirits differed more in esters, such as ethyl octanoate, ethyl decanoate and ethyl palmitate. In turn, alembic spirit compositions differed more in acetaldehyde and acetal. Moreover, column distilled spirits contained four times more esters, 20% more higher alcohols, 40% less acetaldehyde and 10% less methanol than alembic spirits. Spirits distilled with a rectification column were more concentrated in ethanol than alembic distilled spirits, although both distillation systems recovered the same amount of ethanol in the heart fraction.

Pear juice obtained from pear concentrate was fermented at room temperature using Saccharomyces cerevisiae (BDX, ENOFERM, France) as the fermentation microorganism. During the fermentation process, total sugars were measured. High performance liquid chromatography analyses were used to monitor the fermentation process and to characterize the pear wine. The pear wine obtained was distilled with its lees using three different equipments: a glass alembic (a glass pot still coupled to a glass column), a copper alembic, and a glass alembic with the addition of 5 g/L of copper shavings to the pot still. The same distillations were repeated with the wine without its lees (separated by decanting). Several distillation fractions were collected, up to a total of 500 mL of distillate. Gas chromatography was used to identify and quantify the volatile compounds in each fraction, and the methanol and ethanol contents. Based on these results, the heart fraction was defined. ANOVA tests were performed on the heart fractions to determine quantitative differences between some volatile compounds depending on the equipment used and the presence or absence of the wine lees. From this series of ANOVA tests, it can be concluded that the concentrations of the compounds that are considered to have a negative effect on the quality of the distillates (methanol, ethyl acetate, furfural) decrease or do not change when they are distilled in the presence of lees and in the copper alembic. In addition, the concentrations of the positive compounds (ethyl decanoate and ethyl-2-trans-4-cis-decadienoate) increase in the presence of lees for all of the equipment tested. So, it can be assumed that the distillation of pear wine with its lees in copper alembic leads to a better quality product.

Blanquilla pear concentrate was diluted, fermented and distilled to produce the pear spirits. The fermentations were held at the native pH and at an acidified pH of 3.2. Two sets of experiments were performed using a different fermentation yeast and a different distillation equipment. The heart fractions from each distillation (which form the pear spirits) were analysed by gas chromatography. The results showed, in both experimental sets, that reducing the fermentation pH significantly increased the concentration of most of the higher alcohols and decreased the concentration of ethyl acetate in the spirits. Moreover, pear distillates obtained in the first experimental set showed significantly higher concentrations of most of the long-chain ethyl esters (C 6 -C 12 ) compared to those obtained in the second experimental set.

Pear distillates are generally produced from the Bartlett variety because of its rich aroma. In this study, a chemical and sensorial comparative examination of pear distillates from the three main varieties grown in Spain (Bartlett, Blanquilla, and Conference) using two distillation systems (copper Charentais alembic and packed column) was undertaken. Volatile compounds were identified by gas chromatography to differentiate the spirits according to pear variety and distillation method. The Bartlett distillates from both distillation systems possessed higher ethyl ester and acetate and lower cis-3-hexen-1-ol and 1-hexanol concentrations. Despite these differences, a sensory analysis panel could distinguish only the Bartlett alembic distillate from the alembic distillates of the other varieties. In contrast, the panel rated the packed-column distillates equally. Therefore, less aromatic pear varieties can be used to produce distillates with aromatic characteristics similar to those of the Bartlett variety if a suitable distillation process is used.