Dionysian Impulse is about an instinctive and endless discovery of flavours


Originally published at www.turkishwinealliance.com

I was about 13 years old in junior high when I sent an email to Nes’e Bilgin, a prominent professor at Bogazici University. I told her that I wanted to study molecular biology in the future and kindly asked if I could do my semester project in their laboratory. I actually can’t remember the goal of my project, but I remember petri dishes and the centrifuge machine. It took one or two hours of work with the laboratory assistant, but it meant a lot to me. There is nothing more motivating for a student to feel valuable and to be taken seriously. By the time I was 18, I had changed my mind and I ended up at the same university, but in chemical engineering department. I started working in the wine industry and years later, I read about a study called ‘Identification and characterization of yeast species suitable for wine / alcohol fermentation from vineyards of Turkey’ by Professor Bilgin. I was extremely excited and contacted her to hear more about the study. I want to share this amazing project, which is about collecting local yeasts for winemaking in Turkey. Here, with her own words:

How did your project ‘Identification and characterization of yeast species suitable for wine/alcohol fermentation from vineyards of Turkey’ start? Can you tell us about this journey?

I am interested in the preservation of biodiversity. For preservation, the documentation of the differences between species is an absolute necessity. This is at least what I could be contributing as a molecular biologist. Since 2006, I have been a member of “the fruit heritage working group”. As a group of five women of different occupations, we have been running a project to make an inventory of traditional fruit varieties (heirloom fruits), which are under serious threat due to agricultural policies, globalization or other socio-economic factors, and to develop conservation strategies.

The pilot project was carried out in Mugla, in the south-west of Turkey, but we continue to gather information wherever we have a chance. During an early autumn holiday in Bozcaada, I was walking through the vineyards and asking about the local grape varieties of the island (besides the four varieties that we know) when I noticed that the goats were happily eating the grape pulp piled in the vineyards. It was explained to me that the grape pulp was used as an organic fertilizer, so it was poured onto the vineyards. I suddenly realized that the grape pulp coming from the wine producers must be contaminating the fields with commercial yeast used for wine making. The commercial wine yeast is exclusively imported to Turkey, and now contaminating the vineyards of Bozcaada, an island with 3000 years of wine history!

This was the starting point of my project of collecting local yeast before the vineyards get contaminated. (Until then I had no work on wine yeast, I am not even a microbiologist although I had collected some thermostable bacteria from hot springs during 1999, again for a biodiversity conservation purpose). I went back to Bozcaada a few days later, this time with sterile tubes and petri dishes to collect yeast specimens from vineyards. I tried to choose the vineyards where no commercial wine making process was going on. Friends who have been making their own wines from their own vineyards with spontaneous fermentation showed me the way. I was just happy to purify several yeast species and put them into glycerol stocks at -86 oC for cryopreservation and sequenced them for molecular identification. The next year I became curious about how good these local yeast would be in alcohol making compared to commercial yeasts. I made my first wine using one of the yeasts I collected from Bozcaada. It turned out to be a success. I have been collecting yeast species from vineyards since then.

Three years ago I started the above-mentioned yeast project, supported by Turkish Ministry of Food, Agriculture and Livestocks and also by Bogazici University Research Fund. The aim of the project was to isolate yeast species from vineyards, particularly from remote areas in Diyarbakır, Elazığ and Malatya in the southeast of Turkey, where the best wine grapes of the country such as Boğazkere and Öküzgözü grow. Then I carried on collecting yeast from other regions, namely Thrace, Cappadocia, İzmir and Denizli. Until now, I have collected and identified more than 600 different yeast species. Still many more areas need to be studied.

 What kind of challenges did you face?

Not really a challenge. I enjoyed very much the field trips and meeting the local people and learning about the heirloom grape varieties. However, it was also very sad to see some neglected and dry vineyards and the helplessness of the growers, due to inadequate agricultural policies.

Could you tell us about the collaboration you’ve made with Turkish wineries?

Because I started collecting yeast species from Bozcaada, naturally the first collaborations started with the wine makers on the island. One of the wineries was very interested from the very beginning. So already one year after the isolation of the yeasts, we started making small-scale experiments. The results encouraged us to go further for large-scale trials the following year. For this we needed to prepare one of our most promising yeasts for commercial wine making, in dried, granulated form. Two wineries in Bozcaada have been using this yeast for three years. I am very happy that local yeast of the island is now used in wine making from   the local grapes.

A similar work was carried out in Avşa, another island in the Marmara sea, also known with its wine history. A local yeast suitable for wine making is also recovered from Avş It was interesting to notice that the distinct spicy flavor of the wines of the island comes from this yeast.

Besides collecting yeast from vineyards remote from wineries, I am also interested in collecting yeast species from the vineyards of the wineries, although this is a more difficult task because all recovered yeast should be double checked using molecular assays to verify that it is not the commercial yeast used in those wineries, in case they escaped the winery and contaminated the soil. Now several wineries have such yeast species. If used, these yeasts will produce unique wines.

Could you briefly share the outcomes with us?

So far, more than 600 different yeast species have been identified and cryoprotected. Some of those yeasts are wine yeasts, to be used for alcohol production. There are several species of yeast, which can be used to enhance flavors in wine. There are also some valuable yeast species for producing enzymes for biotechnological processes.

Besides preserving the yeast species as part of our biodiversity protection, I believe that the wine yeasts isolated from one region should be used locally with local grape varieties to produce unique wines with a specific signature. Currently this is not the case. Often, wineries use a recommended commercial yeast brand for a particular type of grape, which is often a foreign grape variety. In such a case, how can a winery make a difference and produce a unique wine? In my opinion, Turkish wineries should concentrate more on local grape varieties of our country and their own local yeast to make unique wines that people are eager to try and that have a good chance for export. Only a few Turkish grapes are in use for wine making. I guess it needs more courage to experiment with other local grape varieties that no one has tried before (this statement also holds for local yeast).

Do you personally love wine? And if so, what kinds of wines do you prefer?

I do enjoy wine, but only drink occasionally. If I have a chance, I prefer a variety that I have never tasted before. This year I liked Vinkara’s Hasandede very much (which also fits my description above).  :-)

Special thanks to Nes’e Bilgin for the interview…

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