Pace and duration of heatingDISTILLATION
The “bonne chauffe”: about 13 hours
The first heating, where the wine, is distilled, lasts about 9 hours; the “bonne chauffe” (second heating), about 13 hours.
Different pouring-off temperatures
Analyses of eaux-de-vie show reduced solubility of volatile fatty acid esters at low temperatures, even for small temperature differences.
The low temperature at which the brouillis is poured off, combined with the copper’s reactivity, keep back the fatty acids and other undesirable compounds from the wine. Brouillis is poured off between 13 and 15°C (55-59°F).
Since the brouillis was already filtered when drawn, the pouring-off temperature of the heart of the second distillation is less crucial. It can be higher and varies from 17 to 20°C (63-68°F).
The nature of the “secondes”, which are rich in coarser compounds and the increase in the heating temperature impose a reduction of the pouring-off temperature to achieve a better selection. This takes place between 13 and 15°C (55-59°F).
It can also be noted that the effect of the pouring-off temperature on the insolubility of certain esters seems selective. The most volatile compounds are more subjected to the phenomenon.
Several factors influence the characteristics of the eaux-de-vie
● whether the wine is distilled on its lees or not ;
● the pace and duration of the heating ;
● the decision whether to recycle the “secondes” with the next batch of wine or brouillis and ;
● the percentage of “ heads” and “tails” removed, can all subtly affect the characteristics of the eau-de-vie.
For example, it is possible to “pull” a little more on the “secondes” (draw off more of them), mainly for eaux-de-vie destined for long ageing, to obtain heady notes of brioche.
The distiller adapts his approach according to the kind of eau-de-vie desired.