Distiller’s Workbook exercise 4 of 15

This is the umpteenth draft of the forth lesson in my Distiller’s Workbook. I started it as a book project with the idea of generating interest in distillation by showing a simplified form of it based on the re-distillation of tax paid commercial products.

Over time, the recipes have been elevated from merely low involvement cocktail-centric creations into being a workbook of exercises for new distillers to learn big concepts in distillation on small scale equipment with affordable batch sizes. Hopefully new distillers will be able to learn most all the what-if scenarios of operating a still so they can instead deepen their involvement with the sourcing & processing of raw materials, fermentation, and then the maturing of spirit.

A big focus of the workbook is to expose new distillers to the giant body of research concerning the subject via referencing it. I started by collecting every book on the distillation I could find and that still left a lot of questions. I eventually started collecting forgotten and seldom seen journal articles. These were newly digitized or trapped behind pay walls and I have read hundreds in the last few years. Most professional distillers do not even know this massive body of work exists so I hope to weave it into the content and introduce it to people.

Joseph König’s 19th Century Curaçao

One of the great references to the state of 19th century liqueurs comes to us via the German agro chemist Joseph König, who is often called the father of food chemistry. In his text, first published in 1878, Chemie der menschlichen Nahrungs- und Genußmittel (translated as: “Chemistry of human foods and luxury edibles”), a table is featured that describes the proportions of common liqueurs of the day. One of the liqueurs of particular interest to the cocktail community is a Curaçao (orange liqueur) with unique proportions which definitely differ from what is on the market today.  This exercise will construct a low involvement rendering of a 19th century Curaçao and reveal the secret of its sugar content.

The Curaçao König examined had a specific gravity of 1.0300, 55% alcohol, and 285.0 g/L of sugar. The orange liqueurs on the market today top out at 40% alcohol and typically have somewhat less sugar.

To create a rendering of the 19th century Curaçao described, we first need to find the dissolved volume of 285.0 g/L of non-aromatic white sugar which will in turn reveal the volume and alcohol content required for the distillate.

The dissolved volume of a measure of sugar can be revealed by dividing the weight of the sugar by its density which is 1.587 for sucrose. This means that the 285.0 grams of non-aromatic white sugar has a dissolved volume of 179.6 mL.

It will take 820 mL of spirit to create a volume of roughly one liter when sugared, but we still need to know the pre-sugared alcohol content to arrive at the final alcohol content of 55%. This can be calculated by averaging. We can use the equation: 820 mL(X%) + 179.6 mL(0%) = 1000 mL(55%). The X variable represents the unknown alcohol percentage and works out to be 67.1%. It should be pointed out that accuracy in hitting these numbers is elusive. Feel free to round.

To help with odd sized small scale batches, 285.0 grams of sugar is 34.7% of 820 ml of spirit per liter. To sugar an odd sized volumes of distillate, take your known volume of distillate and multiply it by .347 and you will arrive at how many grams of sugar are needed to maintain the proportions of the 19th century rendering.

The alcohol and sugar content are easy to hit, but the tricky and speculative thing is the amount of aroma. 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 in books of the era like Jerry Thomas’ How to Mix Drinks or The Bon-Vivant’s Companion (1862).

To illustrate:

If you made a 2:1:1 Sidecar with König’s Curaçao it would taste like Tang brand fake juice because there would be too much orange aroma.

1.5 oz. Cognac

.75 oz. 19th century Curaçao

.75 oz. lemon juice

The orange aroma in this recipe would overshadow the cognac, drastically dominating the overtone typically produced, while the modern products of today are designed to produce a more evenly distributed overtone with simple 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 dashes bitters (Bogarts)

1 wine-glass brandy

1 or 2 dashes of Curaçao

squeeze lemon peel;

In this recipe, the aroma of the Curaçao is diluted by the gum syrup so as not to dominate the brandy and bitters. Back then the dash was an important measure for liqueurs, because aroma content was likely far more intense. Notice there is also an or tucked in there. Cocktail recipes used to be dynamic and were expected to be stretched around, but now most recipes are static and do not change. Their proportions are fixed and if you change them to make the drink sweeter or less acidic, it is not the same drink anymore.

To give a grand cru level of orange aroma for our rendering, it is recommended to start with the peels of 12 randomly selected sour oranges per liter. Random selection is based not so much on size, but of color and surface texture of the peels. Sometimes the sour oranges available will look as varied as heirloom tomatoes, each with a different tonality of orange aroma. The idea is that a combination of aroma expressions will lead to extraordinary aromatic tonality. It is common to find Dominican sour oranges in local Caribbean markets, but in the winter the Seville oranges of Spain are sometimes available. If you are lucky, you might even find some from the island of Curaçao.

We have experimented both with using fresh peels and peels dried in a food dehydrator. When dried, the peels definitely loose some volatile aroma. Dried peels lack a certain brightness which may be a desired effect, but we suspect they are traditionally dried mostly for the sake of stability when shipping them across the globe for later processing. We always macerate the peels in alcohol for at least two days before re-distillation. The ability to de-hydrate an orange peel and have it retain any aroma is due to the fixative effect of possibly pectin or wax in the peel. It is unknown what commercial producers do if they are drying peels to manipulate or maximize fixative power.

A 19th Century book on adulterating spirits claims that if the liqueur louches when diluted with water, there is too much aroma. The liqueur can be fixed by diluting with a neutral base of the same sugar and alcohol content then warmed in a sealed canning jar to re-dissolve what louched.

Orange peels are a botanical that vary widely in oil yield. Commercial distilleries test of the oil yield of their peels and then scale the quantity of peels to keep the oil content uniform. The oil yield of peels can be tested with steam distillation in a piece of laboratory glassware call a Clevenger Apparatus. The apparatus differs from common steam distillation in that the oil is collected in a short graduated pippete-like receiver so very small amounts can be measured without facing any loss by removal. Steam distillation, it should be remembered, works to measure oil yield because unlike ethanol, the volatile oils is most botanicals are not soluble in water and therefore separate.


To find a volume of spirits required to re-distill with orange peels, a simple formula can be used:

40%(X) = 67.1%(820 mL) where X = the volume of commercially produced 40% alcohol spirit that will be concentrated into approximately 820 mL of 67.1% alcohol spirit. Not all of the alcohol will be recovered so we add 10% to compensate for an estimate of the loss.

X = 1375. 5 mL + 137.5 mL (10% loss) = 1513 mL

1513 mL 40% alcohol spirit (vodka or a clear rum works nicely)

peel of 12 sour oranges

After at least two days of macerating the peels in spirit, re-distill on high reflux until the thermometer on the still reads 93.3°C. Going past 93.3°C may result in a cloudy distillate.

Adjust the distillate to 55% alcohol and reserve 820 mL then combine it with 285 grams of sugar or scale the sugar up or down to match the exact volume of distillate produced.

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. Some of the sugar may precipitate into crystals which reveals something very interesting about the sugar content; the Curaçao König observed (and many other of the high alcohol content liqueurs of the era) was fully saturated with sugar.

Alcohol cannot hold as much sugar in solution as water, so as alcohol content rises, the solubility of sugar decreases. The alcohol contents of many 19th century liqueurs were very high relative to today and their sugar contents in many cases 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.

According to the early 20th century text, Chemistry and Technology of Wines and Liquors by Herstein & Gregory, many early distilled Curaçoas had a small percentage (about 2%) of an orange peel/alcohol maceration added back to provide subtle color and distinct gustatory features.  The peels they used had a distinct and potent, confusing, bitter/astringency that in small quantities can help define the orange flavor.


Brandy Cocktail

3 or 4 dashes of gum syrup

2 dashes bitters (Bogart’s)

1 wine-glass of brandy

1 or 2 dashes of Curaçoa

squeeze lemon peel; fill one-third full of ice, and stir with a spoon


Crimean Cup, a la Wyndham (for a party of five)

Thinly peel the rind of half an orange, put it into a bowl, with a table-spoonful of crushed sugar, and macerate with the ladle for a minute; then add one large wine-glass of Maraschino, half one of Cognac, half one of Curaçoa. Mix well together, pour in two bottles of soda-water, and one of Champagne, during which time work it up and down with the punch-ladle, and it is ready.

Half a pound of pure ice is a great improvement.


White Lion

1½ teaspoonful of pulverized white sugar

½ a lime (squeeze out juice and put rind in glass)

1 wine-glass Santa Cruz rum

½ teaspoonful Curaçao

½ teaspoonful raspberry syrup

Mix well, ornament with berries in season, and cool with shaved ice.

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