This drink by Mario Kappes, created at Le Lion, is a must-try for every cherry lover. It is the ultimate cherry drink.
30 ml Morand Kirsch
20 ml Guignolet de Dijon by Gabriel Boudier
20 ml Lustau San Emilio Pedro Ximénez sherry
3 Maraska cherries preserved in cherry brandy as garnish.
Preparation: Stirred, sprinkle with lemon zest and garnish with three Maraska cherries preserved in cherry brandy.
On Sunday, 20 January 2008, Professor Langnickel and his wife entered Le Lion in Hamburg. They were seated at table 20, the first table on the left as seen from the bar. They wanted something with brandy or sherry and asked for a recommendation from Mario Kappes, who has a preference for Spanish brandy and sherry, and he first served his Don Raphael, which consists of just these two main ingredients. This drink was well received and the conversation started. More drinks with sherry followed. But at some point Mario ran out of recipes, and finally this moment happened: a new, great drink was born.    
According to Mario, he first put the sherry in a mixing glass, smelled it, tasted some of it too and had the inspiration to combine cherry with it. A cherry that must come with it rich and sweet. He added the Guignolet, but the result was still not quite convincing, as the cherry did not stand up to the sherry. A link in the form of a high-proof alcohol was missing. At first, he thought of common spirits like gin, rum, or something unaged. But now there was also a bottle of kirsch. Until then, it had not been common practice for Mario to mix with eau de vie. But since he wanted to bring the cherry flavours to the fore, it was obvious to choose the kirsch. 
The moment Mario started preparing, Jörg Meyer looked over his shoulder, saw the bottle of Morand Kirschwasser and Guignolet and combined that the next drink would probably be a “Dr Sack”.     Since it fits well with this story, we would therefore like to take a short excursion here and report on the “Dr. Sack”.
Jörg Meyer had become acquainted with this drink in the Old Fashioned Bar in Hamburg, where it was prepared by Achim F. Eberhardt. The latter stated that at the Adlon Hotel in Berlin there had been a regular called “Dr Sack” who always ordered an ice-cold stirred drink made of one third each of kirsch, cherry brandy and gin. At some point, this mixture would also have been called “Dr. Sack” by the bartenders of the hotel. As Jörg reports, it is a rarely encountered drink. He had only seen it in the Old Fashioned Bar and on some old recipe lists of the German Bartenders’ Union. It is a difficult drink to handle because it only works with the right cherry eau de vie and the right cherry liqueur.  
Therefore, we have not come across “Dr. Sack” in old books, which may have something to do with the fact that the drink was only renamed “Dr. Sack” by the bartenders at the Adlon. One can assume that the drink was not developed for Dr. Sack, but was only ordered by him. This thesis is based on our findings in the old books. The mixture of equal parts of cherry eau de vie, cherry brandy and gin can be found in 1935 in the book “The Barkeeper’s Golden Book” published in Zurich under the name “Baimaster”. In the same book, a mixture of two parts gin and one part each cherry brandy and kirsch can be found under the name “Rose Swiss”, and a year earlier in the book “Gordon’s Cocktail and Food Recipes” published in Boston, the “Francaise Rouge” is made from two parts gin and one part each cherry brandy and kirsch. Another curiosity is the 60° cocktail from 1947, which also uses two dashes of Kümmel.
As Jörg Meyer reports, based on his observation, he asked „Oh … a Dr. Sack?“, but this was not known to Mario Kappes and the conversation continued with „Dr. Sack? Nah, I don’t know that one…“ – „Okay, so what are you mixing then?“ – „I’d like to give Mr Langnickel another sherry drink, I have an idea, but I’m not sure if it will work“. Mario stirred the drink, poured it into the glass and realised that it was a very demanding drink that needed a little binder in the form of a lemon zest.  
At this point we would like to quote Jörg Meyer, because he describes the result very aptly: “Mario put the three ingredients, 2 cl PX sherry, 2 cl Guignolet de Dijon/Gabriel Boudier and a good 4 cl Morand cherry brandy into the mixing glass, stirred vigorously, strained into the pre-chilled cocktail glass and added a lemon zest over and into the drink. Mr Langnickel was thrilled! He had to mix a second one immediately and we tasted it: Incredibly complex! Kirsch, pleasantly reduced to drinking strength but clearly tasted. The liqueur miracle from Dijon unfolded a wonderful cherry flavour without even a hint of sweetness. The PX came at the very end, though still a little delicate, almost plummy, it made for a long finish. We changed two things in the next “Langnickel” and both think we have found a perfect recipe. The lemon zest was only squeezed over the drink and no longer added. Instead, there were 3 real Maraska cherries preserved in cherry brandy and Maraschino, which went perfectly with the drink. Secondly, we reduced the cherry brandy by 1 cl to create a perfect harmony of the three ingredients.”  
– „Mario gab die drei Zutaten, 2 cl PX Sherry, 2 cl Guignolet de Dijon/Gabriel Boudier und gut 4 cl Morand Kirschbrand ins Rührglas, rührte kräftig, seihte ins vorgekühlte Cocktailglas ab und gab eine Zitronenzeste über und in den Drink. Herr Langnickel war begeistert! Er musste sofort einen zweiten mixen und wir probierten: Unglaublich komplex! Kirschwasser, angenehm auf Trinkstärke herabgesetzt aber deutlich zu schmecken. Das Likörwunder aus Dijon entfaltete einen wunderbaren Kirschgeschmack ohne auch nur einen Hauch von Süß zu sein. Der PX kam ganz zum Schluss, wenn auch noch ein wenig zart, fast pflaumig, sorgte er für einen langen Abgang. Wir änderten beim nächsten „Langnickel“ zwei Dinge und sind Beide der Meinung, damit ein perfektes Rezept gefunden zu haben. Die Zitronenzeste wurde nur noch über dem Drink abgespritzt und nicht mehr hinein gegeben. Statt dessen gab es 3 echte in Kirschbrand und Maraschino eingelegte Maraska-Kirschen die perfekt zum Drink passten. Zum anderen reduzierten wir den Kirschbrand um 1 cl um es kam zu einer perfekten Harmonie der drei Zutaten.“  
Like the “Dr. Sack”, this drink only works with the right cherry eu de vie and the right cherry liqueur. 
But now we come to the name. The drink didn’t have one yet, but it quickly became clear that it could only be named after the guest. The guest was Professor Langnickel from Cologne, who had been running the Barfly Cocktailbar there for years with his wife Anne. He is a professor of sociology and neither of them had anything to do with gastronomy originally. However, they were both so fascinated by bar culture, the associated drinks and stories that they decided to open their own bar.    
After Jörg had originally thought of a “Dr. Sack” and now – in our opinion – a much better drink, a “Dr. Sack 2.0”, so to speak, had been created, it made sense to turn the “Dr.” into a “Professor” and to name the drink after the guest for whom it had been created. 
- http://bitters-blog.blogspot.de/2008/01/geschichten-der-bar-oder-wie-ein-drink.html: Geschichten der Bar – oder wie ein Drink entsteht: Professor Langnickel. By Jörg Meyer, 25. January 2008.
- http://www.jrgmyr.com/2009/08/professor-langnickel-by-mario-kappes-by_16.html: Professor Langnickel by Mario Kappes, “Hommage” by Jay Hepburn. By Jörg Meyer, 16. August 2009.
- https://www.youtube.com/watch?v=7t4YvDbd4wU&feature=youtu.be: Le Lion Part 4 – Professor Langnickel. By Jay Hepburn, uploaded 5. May 2009.
- https://medium.com/@BarLeLion/how-to-mix-a-professor-langnickel-f3e900798ceb: How to mix a Professor Langnickel. Text by Jörg Meyer.
- http://bildungstrinken.com/3-mario-kappes-don-raphael-professor-langnickel-cus-damato/: Mario Kappes: Don Raphael, Professor Langnickel, Cus D’Amato.
Recipes for Professor Langnickel
2008 Jörg Meyer: Geschichten der Bar – oder wie ein Drink entsteht: Professor Langnickel.  Professor Langnickel. 3 cl Morand Kirsch Vieux; 2 cl Guignolet de Dijon von Gabriel Boudier; 2 cl Pedro Ximénez Monteagudo Sherry. Rühren, in die vorgekühlte Cocktail Schale strainen. Zitronenzeste über dem Drink zerdrücken. 3 Original in Kirschbrandy eingelegte Maraska Kirschen als Garnitur.
2009 Jörg Meyer: Professor Langnickel by Mario Kappes, “Hommage” by Jay Hepburn.  Professor Langnickel. 3 cl Morand Kirsch Vieux; 2 cl Guignolet de Dijon von Gabriel Boudier; 2 cl Pedro Ximénez Sherry; Rühren, in die vorgekühlte Cocktail Schale strainen. Zitronenzeste über dem Drink zerdrücken. 3 Original in Kirschbrandy eingelegte Maraska Kirschen als Garnitur.
2009 Mario Kappes: Le Lion Part 4 – Professor Langnickel. Von Jay Hepburn.  Professor Langnickel. 4 cl Morrand Kirsch; Lustau Pedro Ximénez; 2 cl Guignolet de Dijon von Gabriel Boudier; lemon twist; cherries.
Historical recipes for the Dr. Sack
1934 Harry Jerrold Gordon: Gordon’s Cocktail and Food Recipes. Seite 85. Francaise Rouge.
2 Dry Gin
1 Cherry Brandy
Ice. – Stir well. Strain into Cocktail Glass
1935 George Pillaert: Le Bar Américan. Seite 29. Rose Cocktail.
1/3 Gordon’s Gin
1/3 Cherry Rocher
Garnir une cerise Tumbler
1935 O. Blunier: The Barkeeper’s Golden Book. Seite 78. Baimaster.
1/3 Cherry Brandy
1/3 Dry Gin
1935 O. Blunier: The Barkeeper’s Golden Book. Seite 131. Rose Swiss.
1/4 Cherry Brandy
1/4 Dry Gin
1947 Pedro Chicote: Cocktails mundiales. Seite 239. 60° Cocktail.
Prepárese en cocktelera:
Unos pedacitos de hielo.
Dos golpes de kummel.
1/4 de kirsch.
1/4 de Cherry Rocher.
1/2 de gin Peter’s.
Agítese y sírvase en copa de cocktail.
1956 Patrick Gavin Duffy: The Official Mixer’s Manual. Seite 50. Lady Finger.
1/2 Dry Gin
1/4 Cherry Brandy
Stir well with ice and strain into
1957 Henri Barman: Cocktails et autres boissons mélangées. Seite 56. Lady Finger.
Timbale à mélange, glace
1/2 Dry Gin
1/4 Cherry Brandy
Bien remuer en timbale et
passer dans verre à cocktail.
Mélangeur électr. : voir note.
1977 Stan Jones: Jones’ Complete Barguide. Seite 325. Lady Finger.
Cocktail Glass Stir
1-1/2 oz gin
1/2 oz Kirsch
1/2 oz cherry flavored