Examination of the Varied and Changing Ethanol Content of Commercial Kombucha Products

Abstract

Kombucha is a fermented beverage made by mixing tea and sugar with bacteria and yeast. When kombucha products contain higher than 0.5% (v/v) alcohol, the legal limit for non-alcoholic drinks, they are classified as alcoholic beverages and are subject to relevant federal and state regulations. An efficient headspace gas chromatography technique utilizing an ionic liquid stationary phase is developed to accurately determine the ethanol content in 18 commercial kombucha samples. The range of ethanol in these products was 1.12–2.00% (v/v). The ethanol concentration of two batches of kombucha was analyzed over a period of 60 days under two different conditions. A significant increase in ethanol content of these samples was observed at 4 and 22 °C. The method accuracy was validated by analyzing 3 NIST ethanol-water standard reference solutions.

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Acknowledgements

The authors gratefully acknowledge financial support from the Welch Foundation (Y0026). Moreover, we would like to thank Shimadzu Scientific Instruments for instrumental support.

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Correspondence to Daniel W. Armstrong.

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Mohsen Talebi declares that he has no conflict of interest. Lilian A. Frink declares that she has no conflict of interest. Rahul A. Patil declares that he has no conflict of interest. Daniel W. Armstrong declares that he has no conflict of interest.

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Talebi, M., Frink, L.A., Patil, R.A. et al. Examination of the Varied and Changing Ethanol Content of Commercial Kombucha Products. Food Anal. Methods 10, 4062–4067 (2017). https://doi.org/10.1007/s12161-017-0980-5

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Keywords

  • Kombucha
  • Ethanol analysis
  • Ionic liquid column
  • Headspace gas chromatography