ERP Adopts First Action Method for Ethanol in Kombucha

On September 18, 2016, the AOAC Expert Review Panel (ERP) for Stakeholder Panel on Strategic Food Analytical Methods (SPSFAM) Ethanol in Kombucha Methods, chaired by Sneh Bhandari, Mérieux NutriSciences, approved a First Action Official MethodSM for ethanol in kombucha using gas chromatography. The ERP agreed that the method acceptably meets Standard Method Performance Requirements (SMPRs®) developed and approved through voluntary stakeholder consensus. Standards development activities for the kombucha project are supported by AOAC Organizational Affiliates (OAs), as part of the AOAC working group initiative.

“We were highly impressed by the thoroughness and scrutiny of the methods,” said Justin Trout, COO/Co-Founder of Health-Ade Kombucha, an AOAC OA supporting the kombucha working group. “That type of responsible action is precisely why we came to AOAC in the first place. It was wonderful to see so many sharp and caring minds in the room working to solve our industry’s biggest problem.”

Added AOAC Executive Director James Bradford, “AOAC’s working group initiative is a valuable mechanism that allows OAs to work on issues that most impact their industry through standards development. The output of standards development is a real benefit of the process to OAs.”

AOAC standards are needed for an analytical method to measure the low levels of ethanol in kombucha. Since kombucha may contain more than 0.5% alcohol by volume (ABV), some kombucha breweries have elected to brew their kombucha under state beer or wine licenses–while many have chosen to tightly control their production processes and offer nonalcoholic beverages. Standards and methods are critical for industry to build trust with customers, retailers, and distributers.


Submitted by NaturPro Scientific, a single-laboratory validation (SLV) of a method is described for determination of ethanol in kombucha by headspace gas chromatography-flame ionization detection (GC-FID). The method uses headspace autosampler to introduce ethanol vapors into the gas chromatograph. Ethanol from the sample is vaporized into the headspace autosampler, thereby preventing some matrix interference. n-Propanol is used as an internal standard. Ethanol is estimated as ABV.


Precision was determined by analyzing six replicates of each sample of commercial kombucha over a minimum of 2 days. Accuracy was determined by testing duplicates at each of three spike levels of pure ethanol into control kombucha over 3 days. The method was shown to be applicable for determination of 0.1-3.3% ABV in aqueous kombucha tea beverages.


In general, the ERP agreed that the method acceptably meets the SMPR, with valuable method performance information provided, particularly for accuracy and precision. In addition, the method is simple, straightforward, and highly promising. The method was adopted by the ERP as First Action Official MethodSM 2016.12.

Full coverage appears in the November/December 2016 issue of Inside Laboratory Management.