Proof Positive  [08.12.20]

Aroma-conserving distillation - this term best describes the field of activity of the Hohenheim Distillery for Research and Training. Its success is demonstrated by the fact that the products manufactured there repeatedly achieve top positions in the international quality test for spirits by the German Agricultural Society (DLG) - this year, too, with four gold and one silver medal. The core task of the Distillery for Research and Training is not the distillation of spirits, but rather research into the relationship between distillation technology and aroma substances. The aim is to develop recommendations and recipes for the 13,784 small distilleries throughout Germany in order to improve the prevailing quality of spirits in general. A new focus of the research is the question of how to ensure the utilization of fruit trees in order to promote the preservation of these important biotopes.

 

"What matters with distillates is to preserve the fruit aroma," said Dr. Daniel Einfalt, Director of the Distillery for Research and Training. "The art of distillation is to separate the aroma substances as cleanly as possible and to have as much of the good tasting good aromas and as little of the bad ones as possible in the finished product."

"Some people like it when the schnapps tastes spicy. But when it burns on your tongue, the master distiller has not done his job well. Then too many of the bad aromas have ended up in the final product. Because alcohol itself is not spicy, but rather soft, just like good Russian vodka," explains Prof. Dr. Ralf Kölling-Paternoga, Director of the Department of Yeast Genetics and Fermentation Technology.

 

In search of the decisive aroma cocktail

"We still know little about the substances that make up a good flavor," he continued. "What is the decisive factor that makes a pear brandy? We only know that it must be a whole cocktail of chemical substances. But what does its composition look like in detail? In the search for it, we work closely with Prof. Michael Granvogl from the Department of Food Chemistry and Analytical Chemistry, who is an expert in this analytical part."

In addition, Kölling-Paternoga and his team are also investigating how the yeast cells responsible for the fermentation process function: What nutrients they need, what influence they have on the aroma, and how they can be made to produce the desired spectrum of aromas in the end.

 

Hohenheim spirits prove their top quality

Research work that pays off: The regular awards from the DLG show that Hohenheim spirits are distinguished by their high quality and enjoyable taste. This year, the examiners awarded four gold and one silver medal to the Hohenheim products: Gold was awarded to the plum brandy, the mirabelle plum brandy, the whisky, and the wine yeast brandy aged in acacia barrels. The Kirschwasser received a silver medal.

"Of course we are very happy about the awards. They are not least also the merit of our master distiller Oliver Reber. Because you need a person who knows how to get good flavors into the product," explained Dr. Einfalt. "And these awards give us an objective picture of our current capabilities. It is important that we can show these quality criteria, because they are necessary to appear authentic and to be able to give recommendations to other small distillers and the spirits industry."

"However, it is important for us to point out that our spirits are produced exclusively within the framework of research and teaching activities," emphasized Einfalt. "Therefore, unfortunately, we often have to disappoint interested customers. Because our work here is primarily research-oriented, we only ever produce small quantities and do not always have all types in stock."

 

In the last ten years, 50 percent of all submitted spirits received DLG Gold

The Distillery for Research and Training has been participating with its products in the DLG quality tests for over 45 years. With constantly increasing quality, as the DLG medal table from 1974 to 2020 shows: While 11 percent of all Hohenheim spirits were awarded gold in the assessment years 1974 to 1990, the proportion of gold medals has risen continuously over the decades: from 20 percent gold in the years 1990 to 2000 to 25 percent in the following decade and currently 50 percent gold from 2010 to 2020.

 

Research aim: improving the quality of spirits in general

The long-term goal of all research efforts is to improve the quality of spirits in general. For example, the scientists are developing methods to reduce the methanol content in spirits or to reduce disturbing foam formation during the distillation process purely physically, so that the addition of chemicals is no longer necessary. These topics are thus always related to sustainability and the bioeconomy.

"Especially for small businesses, quality is a decisive criterion in marketing. For this reason, many small-scale distillers have their own products sensory tested by independent testing panels of the small-scale distillers' regional associations. On average, these sensory test results reveal a high potential for improvement: Every two years, for example, around 1,500 spirits are evaluated in North Württemberg, and around 37 percent of these show noticeable quality deviations or even significant defects," said Kölling-Paternoga describing the problem.

 

Digitalization for better spirits: Distillery 4.0

In order to gain a comprehensive insight into the various material flows during distillation and to understand what exactly happens in the plant, the scientists had one of their copper distillation plants digitized for around 40,000 euros. "Ultimately, we are looking for the optimal distillation process depending on the starting material for the best possible quality and also with optimized energy consumption," summarized Einfalt. "This must also lead to a targeted regulation of the distillation process."

On the basis of the digital data, the scientists want to derive recommendations and work instructions for distillery operators so that they can use the appropriate recipes to produce the highest possible quality and best tasting brandy. "With the Distillery 4.0 project, we want to support above all the approximately 14,000 small distilleries in Germany, which of course cannot have their plants digitized themselves - the technical equipment would double the price of a plant," said Einfalt.

 

Promoting biodiversity: Distillations of orchards to preserve orchard meadows

In addition, a research project sponsored by the Ministry of Rural Areas and Consumer Protection Baden-Württemberg (MLR) will soon start: In the three-year project, scientists will study fruit distillates from fruit trees in order to find out how this nutrient-poor fruit can best be fermented and how it can be distilled optimally.

This should also make orchard meadows economically attractive for farmers again, as the number of orchards in Baden-Württemberg has been declining steadily for decades. The state's declared aim is therefore to preserve and promote these habitats, which are important for biodiversity.

 

Text: Stuhlemmer / Translation: Neudorfer