Expert Review Panel for Kombucha Tea

4. Based on the supporting information, is the method written clearly and concisely? If no, please specify the needed revisions.

1. The GC oven program in Appendix A needs corrections, specifically for units and numbers given. 2. Calculation for %ABV needs to be revised to include conversion of ethanol weight to volume. 3. Specify concentration of CCV to be used. 4. Specify suggested ions for quantitation and qualification ions for identification of ethanol and butanol. The method is fairly simple and the concepts used are easy to understand. The use of MS detection can help to verify peak identity; this may be an issue when analyzing Kombuchas with volatile flavor components which could interfere.

5. Based on the supporting information, what are the pros/strengths of the method? 6. Based on the supporting information, what are the cons/weaknesses of the method?

The large dilution of Kombucha prior to analysis will require the use of 100 mL flasks, which could be cumbersome.

7. Any general comments about the method?

Method appears to work well for this determination, if the calculation issue with %ABV is addressed. Also, for better accuracy at very low %ABV levels, it is suggested to decrease the concentration of internal standard added to the samples and standards.

Do you recommend this method be adopted as a First Action and published in the Official Methods of Analysis of AOAC INTERNATIONAL? Please specify rationale.

Yes, if correction is made to the calculation of %ABV, I recommend this method be adopted for first action.