This post is very old and an updated version is in my Distiller’s Workbook exercise on Curacao.
In a post way back in 2010, I published some numbers gleaned from a 19th century book on separation science. Among them were proportions for an orange curacao.
Joseph Konig dissected the curacao of the day and reported this: Curacao 1.0300 s/g, 55% alc. by volume, 285.0 g/l sugar
The orange liqueur studied had significantly more alcohol than present day products and somewhat more sugar (the ending contains a surprise about the sugar content so read on).
285 g/l of sugar has a dissolved volume of about 190ml
This means that for the spirit to end up at 55%, it has to start at 68%
The alcohol and sugar content are easy to hit, but the tricky thing is the amount of aroma. Konig provides additional information like the amount of extract minus the sugar (sometimes called dry extract) and the mineral content. These figures may be used to extrapolate the amount of aroma in the product, but I haven’t yet figured out how to put them to use.
Liqueurs of the day were often graded and the highest grades had the highest alcohol and sugar contents. The highest grades likely also had the highest dissolved aroma contents. These grand cru products likely were not intended for use the way we do today which would be why they were typically only used in dashes.
If you made a 2:1:1 side car with konig’s curacao it would taste like Tang brand fake juice because there would be too much aroma.
1.5 oz. Cognac
.75 oz. 19th century Curacao
.75 oz. lemon juice
The orange aroma in this recipe would overshadow the Cognac, drastically dominating the overtone produced, while the modern products of today are designed to produce a more evenly distributed overtone with modern proportions.
Drinks of the 19th century looked more like this brandy cocktail from the Bon Vivant’s Companion:
3 or 4 dashes of gum syrup
2 do. bitters (Bogarts)
1 wine-glass brandy
1 or 2 dashes of Curacao
squeeze lemon peel;
The aroma of the Curacao is diluted by the gum syrup so as not to dominate the brandy and bitters. Because the aroma of liqueurs was likely so intense back then, the dash was a more important measure.
To give a grand cru level of orange aroma for Konig’s recipe, I would recommend the peels of 12 randomly selected Dominican sour oranges per liter (I used Del Pueblo). Random selection is based not so much on size, but of color and surface texture of the peels. The idea is that a combination or aroma expressions will lead to extraordinary aromatic tonality. The still should be stopped before the temperature gets too high so as not to produce a cloudy distillate. Such a high alcohol content makes it a challenge to dissolve the sugar by simply stirring, so warming the liqueur in a sealed canning jar is a nice trick to speed up the process.
Recipe #188 of the Bon Vivant’s Companion is for an English curacao and the author (Jerry Thomas) recommends clarifying the liqueur with alum and carbonate of potash to render it clear mimicking the distilled products of the era from France.
The curacao that Konig examined in the 19th century might have also been clear and therefore the product of simple distillation like the recipe implied above.
Executing the recipe reveals something very interesting about the sugar content. A small portion of rock candy sugar crystals form at the bottom indicating that the solution was super saturated (hence needing heat to dissolve the sugar). Alcohol cannot hold as much sugar in solution as water so as the alcohol content rises, the solubility of sugar decreases. The alcohol contents of 19th century liqueurs was very high and their sugar contents likely could have been pushed to the maximum of solubility. This means that 19th century Benedictine and Chartreuse likely had as much sugar in them as their high alcohol contents could hold.
As interesting as experiencing history is, I hate bartending by the dash. These liqueurs read romantically, but (if I’m correct on the aroma level) are garish and baroque. Oh well, onto the next project.