advanced limoncello basics

Recently on egullet I attempted to help a few people troubleshoot their limoncello. They were experiencing cloudiness and did not know what to attribute it to. I suspected pectin while others thought terpenes. The conversation turned to terpene removal which made me look for other research out there.

As it turns out, limoncello is economically significant enough that a few PhDs have looked at it in depth.  Some of the studies try to characterize limoncello chemically so that consumers can be protected from fraud and adulteration. Though some aspects of the studies are intimidating, there is still great practical stuff that home producers can learn from these studies.

I found a few papers and I’ll give a bullet point run down of the good bits.

“Analysis of volatiles in Limoncello Liqueur and Aging Study wiht Sensory” by Neil C. Da Costa and Theodore J. Anastasiou

**”it certainly does not contain any lemon juice”

**”but must be transferred to the freezer before serving” These guys posit the idea that limoncello is fairly perishable. Homemade is best because it can be freshest. Their study wonders how limoncello changes as it ages.

**They keep it in the freezer to minimize reactions of the extracted oils with water and ethanol as well as with air and light.

**Due to shipping, warehousing, etc. “there is a higher likelihood of commercially available Limoncellos having less of a true flavor profile than their homemade counterparts”. This is their hypothesis anyhow which they will test by looking at how significantly limoncello changes as it ages.

**They present a very long list of compounds they were going to cover but one I was concerned about was pectin which I couldn’t find in their list.

**They prepare their own limoncello recipe by following a Washington Post article: Grisco, J. Limoncello Recipe. The Washington Post, December 7, 2009 (this link was missing for a while but provided by an awesome commenter. thanks KM!)

**”seventeen large store-bought organic lemons (approx. 175g. each, approx 3000 g total) were washed, dried, and carefully peeled as to minimize the amount of pith. the peels were submerged in 1500ml of grain alcohol (95% abv, 190 proof). This mixture was allowed to stand at room temperature for 14 days with brief stirring every other day. After 14 days the spent lemon peels were removed by filtration leaving a dark yellow solution. 1700g of a simple syrup solution consisting of equal parts (1350g) water and granulated sugar were then added to the extract, resulting in an opaque yellow emulsion. this emulsion was allowed to sit at room temperature for an additional 21 days, again stirring every other day. …. the approximate alcohol concentration was calculated to be 50% (100 proof).”

**They didn’t use any terpene separation!

**One cool part of the technical stuff is the descriptors that accompany the analysis of “key volatile components”.

**After aging, some of the terpenes hydrolized/oxidized

**Aldedydes in such a high alcohol content formed acetals (which also happens to distillates when they age)

**There was ester formation (again this happens to distillates! and of course it is going to inspire another blog post!)

**”organoleptically, the fresh limoncello concentrated extract was described as strongly citral, fresh, lemon curd. the aged concentrate extract was more oxidized lemon, less fresh, heavy lemon, missing lower volatiles, lower citral. … the biggest difference detected was a reduction in the concentration of the highly volatile monoterpenes as they became oxidized, which gave rise to the loss of fresh citrusy notes. in addition the harsh gasoline, oxidized terpene note of p-cymene was increased, which had a negative impact on the aged sample.” … “the various ethyl ethers formed were not perceived as giving significantly negative notes to the aged sample.”

**They present two sensory “spider graphs” which are pretty cool and really intuitive. hopefully I can paste the spider graphs in here because they are a tool we should probably see more of.

**They preferred the fresh but they didn’t find the aged stuff too terrible.

“Analysis of Some Italian Lemon Liqueurs (Limoncello)” by Versari Andrea, Natali Nadia, Russo Maria Teresa, and Antonelli Andrea

**For starters those names sound like people that would know limoncello…

**”a total production of 15 million liters of Limoncello per year is estimated.” wow.

**When they detail the process they state that peels are infused in 95% ethanol for 2-7 days. Then it is diluted with syrup to an average alcohol content of 32%.

**”…Limoncello contains several volatile and nonvolatile minor compounds (ca. 2%), which are fundamental for its sensory characteristics. The former are terpenic compounds, which form the essential oil, and the latter include several classes of nonvolatile compounds with potential health-related properties, such as flavanoids, coumarins, and psoralens.”

**The presence of these nonvolatile constituents are sometimes used to tell whether an essential oil was cold pressed or steam distilled the latter being seen as inferior.

**They compare 12 samples by a variety of criteria

**The sugar contents were a surprise: 182, 186, 186, 185, 202, 277, 265, 223, 264, 199 g/L so there seems to be two different styles; a low and high sugar content.

**The samples also had notable citric acid contents that were all over the map: 2044, 438, 190, 209, 475, 152, 83, 1059, 172, 395, 846, 301 mg/L. I suspect the acid is added as a powder as opposed to being from fresh lemon juice. They are listed in the same order so the style that has a high sugar content in most cases also has a high acid content. Unlike the previous paper that sees limoncello as not being sour, quite a few commercial producers interpret it as a sour liqueur. I have no opinion personally.

**They also cover the ethanol content, acetaldehyde, ethyl acetate, methanol, propanol, and i-butanol content. For ethanol: 32, 31, 31, 31, 30, 30, 29, 40, 30, 27, 29, 28.

**A lower alcohol content than 31-32% might affect stability and lead to essential oil separation (those terpenes again!) while “higher values might not fit the consumer’s preference”. “in fact, Limoncello is considered a beverage, not a spirit.” On egullet someone mention 30% as being a key number for terpenes coming out of solution. This data makes me wonder if they are correct, and what would happen to the stability of the product that had 27%. Is that low number the producers intention or an accident?

**Speaking of accidents.. one sample had a declared ethanol content of 35% but 40% was found…

**”methanol showed values below the legal limit, whereas acetaldehyde content was above the regulatory limit for neutral ethanol which is set at 5 mg/L of anhydrous alcohol.”

**They find strange congener values that make them wonder if low quality grain alcohol was used or if the syrup in some cases had started to ferment. The occurrence of glycerol and high acetaldehyde level plus low methanol levels supports the hypothesis that high quality ethanol was used but some of the syrups likely started to ferment. Very weird. Kind of gross.  It sounds like some producers do not have control of their product.

**from their conclusion: “Citric acid content indicates the addition of lemon juice.” I do not think this is conclusive. Citric acid powder is easy enough to buy and the juice has all sort of oxygen sensitive compounds. Granted they have a lot of juice laying around…

**”Ethyl acetate, acetaldehyde, 2-methyl-1-propanol, and glycerol are most probably related to the occurence of microbiological activity in the sugar syrup used in the limoncello formulation” -Gross


Conclusion. Terpene separation is not a part of limoncello production. But the pectin issue wasn’t resolved. They might even be using a pectic enzyme but in my understanding that might produce methanol that would make the authors note the phenomenon so maybe they are not? In the mean time just peel it thin! And please don’t let your syrup start to ferment.

This Day in History: 1879

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I’ve been collecting books from the University of California’s wine and liquor research bibliographies for a long time now. I’ve finally turned up a few oldies that reveal a tiny glimpse of what was being imbibed in the hay day of the cocktail era.

The sources mainly focus on wine and distilled spirits which were studied to death to provide really detailed finger prints of what people were drinking well into the 19th century.

Liqueurs (think Cointreau, Chartreuse, etc.) were not studied in so much detail. They were economically very significant because they are taxed so high, but most all researchers just throw up their hands in confusion when analyzing them because of the variety. All of the metrics they put liqueurs through showed massive variance that barely seems useful unless you are just curious about one proprietary product. (and luckily I am!)

Herstein and Gregory’s The Technology and Chemistry of Wines and Liqueurs (1935) is brilliant when it comes to wines and spirits analyses but becomes kind of silly in their liqueurs chapter. According to Herstein and Gregory, liqueurs come in grades like average (sub divided into single strength and double strength), good, very good, excellent. The biggest difference between average and excellent is an increase in alcohol as well as sugar. Of course there is no empirical data to back up their categorization, but they do also provide recipes for the same liqueur of different grades to show how proportions of ingredients changed.

The text has tons of recipes but is written in the “shovelware” style. Many look like they were plagiarized and never tried. Some don’t seem to work because they are missing information like how big the recipe is supposed to be. The recipes are prefaced with the warning that they are only examples, but it is still half assed for an otherwise incredibly thorough text.

When you go back this far in time (1935) the bibliographies are dominated by foreign languages. Many of the charts are borrowed from these foreign language sources and are hard to track down. Herstein and Gregory borrow a chart from Leach (Leach, a. e. Food Inspection and Analysis. New York 1920) who borrowed it from the famous German chemist Joesph Konig. Konig’s (I’m missing an umlaut on the “o” of his last name) book Chemie Der Menschlichen Nahrungs- Und Genussmittel (I’m not sure if I cited the title correctly) has many editions which goes back to the end of the 19th century.

Konig has a chart that analyzes many famous liqueurs for many metrics. The only numbers of value to us are specific gravity, alcohol content and sugar content (if you know what ash content means let me know).

here goes: (1879 edition)

benedictiner-bitter specific gravity 1.0709, alcohol 52%, sugar (g/L) 325.7

creme de menthe                          1.0447,              48%,                  276.3

annisette de bordeaux                   1.0847,              42%                    344.4

curacao                                          1.0300               55%                    285.0

The 1918 edition doesn’t seem to have a chart but rather summarizes the results in a paragraph. (it took me a while to figure that out because I don’t speak German. I just found all of the search terms in a paragraph with most of the figures. I think the paragraph also references another text where the data may be borrowed from.)

another edition adds…. (1920)

ginger                                              1.0481              47.5%                   259.2

kummel                                           1.0830              33.9%                   311.8

pfefferminz-likor (pepper mint)       1.1429              34.5%                    473.1

chartreuse (green?)                        1.0799             43.18%                   343.5

punsch (schwedischer)                  1.1030               26.3%                   332.0

maraschino                                      1.1042              31.76%                 346.8

This famous chart also comes up other texts like The Chemical Engineer, Volume XXI. 1915 (a journal)

The significance of this all is that we see a very early sugar and alcohol ethic of the products. The majority of the emotional content of a drink comes from these relationships plus acidity (we make the assumption that lemons haven’t changed much in acid over 120 years)

Since then alcohol contents have gone down. Sugar contents have stayed the same for some products and gone down slightly in others. Cointreau is slightly less sweet than 280 g/L and I’m pretty sure the Chartreuses are down into the 200’s as well which would be the biggest migration. Which Chartreuse was not explicitly specified, but if probability favors green, the alcohol has also increased significantly.

The last commercially bottled Swedish Punsch I came across (Carlshamns Flag Punsch) had 1.082 specific gravity, 26% alcohol and 267 g/L sugar. Switching bottlings would definitely change the emotional content of a drink with Swedish Punsch.

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Reconstructing Cointreau

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In a recent post I deconstructed Cointreau to learn its many mysteries.

I learned Cointreau’s sugar content to tell more about it’s structure. I translated the g/L sugar measure to something volumetric to explain the starting alcohol content before dilution by sugar down to 80 proof. This sounds complicated but I can now reassemble the shell of the liqueur in under a minute.

What I never figured out is the extract intensity of the oranges which I figured I could only do by taste (really rustic recipes say about three oranges).

Well, at the restaurant I got a couple cases of stunning sour oranges and I put all the peels in high proof alcohol to make a flavor concentrate. After a couple weeks, the concentrate was ready to strain and make a few liters of Creole Shrubb with Cointreau’s intuitive to use proportions.

The sugar content was no problem to hit perfectly and getting very close to the correct alcohol content was not that big a deal, but wow is judging the intensity tough.

Orange is such a cloyingly outrageous flavor. As soon as you taste or even smell one sample you have no chance of differentiating the other. You can’t even tweak it in the same sitting. The aroma fills the room and you must revisit everything the next day. Well after patient days I think I nailed a realistic comparison down. No problem except it brings up some more questions.

What does my infusion of orange peels have that Cointreau’s distillate leaves behind? Terpenes?

Do I even want the same intensity as Cointreau? or do I want more? I primarily use Cointreau in tart drinks like Sidecars and Margaritas. Unfortunately, I also primarily deal with people that for some reason can’t handle a classic 2:1:1 Margarita because it is too tart, too refreshing, too subtle & too elegant. The unbalanced nature of cocktails in general makes the Margarita plagued by the sweet-tart phenomenon of amateur dessert wines. The rules of balanced wine says that as sugar and acid increase in a wine, extract has to increase as well or the wine will taste like hollow artificial candy.

In the unbalanced direction driven nature of cocktails, the “sweet-tart” is fun and desirable by some but feared by so many that need to be weaned onto cocktails. If you increase the orange extract could you have squeamish drinkers enjoying classically proportioned Margaritas? I’m going to try and figure it out.

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gambling on a gallon of wine…

really liking cynar, i thought i’d take a stab at making something similar at home. the infamous loved or feared liqueur claims to be about the artichoke, but i suspect there is more going on. creating something similar is going to either be easy or turn out to be far more complicated than anyone has ever given the spirit credit for… probably the latter.

what i’ve learned so far is that cynar is a distilled spirit that is cut with what is probably only water to 16.5% alcohol where anything wine like would be highly perishable… its also flavored with other botanicals besides the artichokes and get a pretty reasonable sugaring… i also wonder if they use something like potassium sorbate as a preservative considering the low alcohol… from the artichokes, i think they only use the leaves which could easily be a byproduct of a cannery… one mans trash another man’s treasure… upon further tastings, the bittering agent is probably really important. more than any artichoke character, the bitter botanicals is probably what makes or breaks the liqueur… i suspect it is some elegantly applied quinine… but with who knows, maybe rhubarb root or something weird and only mildly bitter playing a supporting role…

my strategy to make a similarly interesting liqueur (not exactly a replica) is to make an artichoke wine, fortify it, and add extra botanicals to make it as interestingly bitter as cynar… cynar likely has citrus peels in its botanical line up but i thought more fun would be strawberry (or i could add pomegranate seed if it needs more help down the road) and use coca cola as my backdrop. to me cynar’s allure is its sexy bitter kola character… after unsuccessfully playing with kola nuts it may be best to get this botanical’s help straight from the masters… and the wine will turn coke’s dreaded corn syrup into a useful alcoholic solvent… this just started fermenting tonight and many months later on i can revisit the recipe and bitter it up as necessary…

“strawberry kola artichoke wine” (for one gallon)

2 liters coca cola

1 liter water

414 grams of sliced and hulled organic strawberries (a couple pints)

1005 grams of sliced and cleaned artichokes (5 medium sized)

i cut the stems but did leave the hearts in as well as the leaves…

this all went int a stock pot and was boiled together for an hour…

i strained everything into a carboy but only had about 1.5 liters at 13 brix. to get a potential alcohol of 10% i need a brix of 18 and had to complete the gallon with a 21.5 brix syrup… you may end up with different results here so its best to do the algebra yourself. authors like amerine recommend fortified wines only ferment to 10% or so before they are fortified so i’m taking their advice…

i then added a campden tablet, 1/2 teaspoon of pectic enzyme, and pasteur’s champagne yeast

its probably 80 degrees in the house and this started fermenting very quickly…

**my previous attempt at an aromatized wine, the “hercules” is coming along nicely and encourages these styles of rustic liqueurs… there are lots of mistakes to learn from but hopefully i can disclose them all…


so i just racked this wine to the secondary fermentor and saved myself a sample taste. the wine so far rang in at approximately 6 brix so it has about 2.7% alcohol worth of fermenting to go to be dry… what i racked off so far looked very untypical… there was the most intense scum that stuck to the bottom and the yeast was concentrated in it… everything that was racked off looked rather clean relative to my one gallon “hurcules” wine… i’m wondering if this is a result of the unfermentable gums that are in coca cola? i know this is young stuff and i don’t really understand how things evolve but i have no confidence that it would taste like i intended… the acidity is there somewhat so its not too flat tasting, but i will have to measure it for a comparison to other wines. the artichoke flavor is there but the cola seems to have faded alot. hopefully aging and a little botanical embellishment may help it out…


so this wine sat around for a quite a while after it finished up in the secondary fermenter. after racking the wine i was left with 3.5 liters and i added 2 liters of miscellaneous 80 proof spirits to bring the 10% alcohol wine into the 20%’s before i increased the sugar to 16% by weight (required 1003 grams) leaving it in the very high teens of alcohol. i also did add 1 oz. of my quinine tincture. the result is pretty cool but not exactly mind blowing. i used white sugar but things taste really caramely which could be due to the bottle of cruzan black strap in the fortifying mix. so over all interesting shades of this and that but the product is definitely not as complex as cynar. i do feel like it grows sweeter as you drink it so much so that you crave some acidity. maybe i did capture some of the cynarin… so i just need some better botanicals. hmmm… wormwood, gentian, and orris?

Newman’s Own Creole Shrubb

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Quite a few months ago I was invited to present a cocktail at a charity event in the posh space atop the state house. The restaurant gave me the okay to spend a little money so of course I spent every dime they gave me solely on Seville oranges (aka sour oranges). These magical orbs are rarely imported and I’ve only seen them available during citrus season in the winter. They are not like the bland domesticated varieties we know. Sevilles are tart and pungent with a wild heirloom quality. They are hard to work with and have lots of learning curves but I still highly regard them. I bought them intending to use the juice for the event and save the peels for myself to make orange liqueur for the bar, but little did I know there was a fraction of the juice I anticipated. From 33 Seville oranges I only got 750 ml of juice and at that point in the day I had to leave soon for the event. Each drink was supposed to use an ounce and I was supposed to serve 150 drinks so I was in real trouble. This led to the Seville cheater when I added citric acid to normal orange juice with a healthy dose of reagan’s orange bitters to synthesize that wild heirloom character. Luckily the results were quite satisfying and the drink was a phenomenal success.

bronx cocktail (named after the bronz zoo and using my theory that it was designed for tart wild oranges and therefore a sour drink)

2 oz. gin

1 oz. sweet vermouth

1 oz. seville orange juice (fake or real)

stir, and decreasing the gin is not wrong and means it is easier to justify a second round.\


For the event I actually only used the cheater juice and I saved the real stuff for the pastry chef to make sorbet with. Unfortunately I have no recipe but the sorbet was stunning. It totally captured all the wild flavors and used the natural inherent acidity of the juice. A little bit of my previous batch of creole shrub was also added so the alcohol could enhance the texture.

It was ten minutes before I had to leave for the event and I had a large pile of zest sitting on the counter top which probably added up to a couple pounds. My goal was to eventually, in small periods of free time, turn this pile into ten liters of creole shrub using whatever rum of character I could come across. So on the run, I put all the peel into a three liter mason jar and covered it with rum (appleton’s VX). I figured I could add more rum, get a bigger container and eventually add my sugar.

The plan seemed reasonable but I was over looking the fact that my rum was only 80 proof and would be diluted by sugar so I’d end up with less alcohol than the real stuff. Though ideal proof would have to be sacrificed to make the handmade shrub economically viable. But to add insult to injury, I didn’t dehydrate my peels because I had no time. In Martinique they dry the peels out in the sun. If you think of dehydrating our normal sunkist oranges it doesn’t make that much sense, but for Sevilles, their peel is spongy and full of moisture which would further dilute the proof of the final product. Another hole in my rushed strategy was that I only estimated the volume of liqueur I could produce from 33 oranges. When you make liqueurs you need to be concerned with alcohol, sugar, and other total dissolved solids. The total dissolved solids in this case is the weight of orange peel added to flavor the shrub per liter. Too intensely orange is frightening and not enough is bland. I am merely hoping to figure my intensity to taste which seems reasonable but isn’t exactly scientific. If you really wanted to figure it out for clement’s creole shrub you would have to cook out the alcohol of a significant volume, refill what was lost with distilled water and see if you can measure the total solids (sugar and orange oil) and subtract just the sugar [this actually turns out to be incorrect but these were just my very first experiments]. This is not practical for my small production so I apparently have to rely on a tasting panel and hope to get scientific next time around.

Hopefully next time is this week because I just bought six more Sevilles yesterday at tropico in roxbury (I thought you couldn’t get them anymore but apparently not) and hope to make a small completely measured batch so I have something realistic to go with next year and I will definitely dehydrate the peels. see you next week for the update!


From my 33 oranges, I yielded about 8.5 liters of exceptional Creole Shrubb. I used quite a lot of mixed up rums that I had laying around and the product was still stunning. To my surprise everyone (my kitchen crew) preferred my version to clement’s iconic product. I am still kind of skeptical. My intensity is at a comparable level if not a little more intense than clement, but what I noticed is that these oranges have serious organoleptic qualities and what I got from Specialty Produce tastes really different than clement’s Martinique oranges. Putting the difference into words is very difficult but there is more to these bitter oranges than meets the eye. I think my solution is to try and figure out where my product comes from and celebrate it. I keep seeing a growing interest in botanicals, but a lack in curiosity or information on where exactly what you use comes from. Wine isn’t the only thing susceptible to terrior. Consistency is overrated and I simply recommend celebrating the differences.

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