Tej takes on its yellow, cloudy and effervescent nature due to the contents of the yeasts present in it. These yeasts largely come from the
Saccharomyces genus; which are commonly the catalysts of the reaction when converting sugars into
ethanol. Yeasts in particular are some of the most dominant microorganisms present in tej. Research into these yeasts determined that over 25% of the yeasts that ferment tej are from the species Saccharomyces cerevisiae. Other yeasts, such as
Kluyveromyces bulgaricus which made up 16% of the total, also contribute to the fermentation process. The yeasts specifically belonging to the Kluyveromyces and Saccharomyces species have also been reported to be important in the fermentation of various other wines. Tej has been studied due to its various chemical and nutritional properties as well as its unique fermentation process. A study by Bahiru, Mehari & Ashenafi (2001) found that each tej has physico-chemical variations. This is a result of the different stages that the randomized
microflora, present in the ingredients of tej, are in. The amount and type of the specific yeast species present in each tej also creates differentiations, as it results in differing chemical compositions that would create variations even if the tej came from the same source. It is also due to the spontaneous nature of fermentation which makes each tej unique. The honey which was used to create tej in the past, and still today, was generally collected from wild nests or produced in 'traditional barrel-type hives'. As a result of this gathering method, the honey also contained wax, pollen, bees and broken combs. These additions; however, served a purpose in the production of tej. The remaining wax floating on the surface of the mixture can make the fermentation process more
anaerobic (less oxygenated) and the pollen functions as a yeast nutrient. The use of honey in the production of tej also results in a significant level of sugar content. Sugars constitute about 80% of honey and dependent on the ratio of honey to water used to create the specific tej, the overall diluted sugar content of the honey generally ranges from 13 to 27%. Alcohol content can also vary greatly between different types of tej. The typical range is 7 to 11% or 7 to 14%. Research has been conducted on tej with alcohol content levels as low as 2.7% and as high as 21.7%. The
pH of tej was found to range from 3.02 to 4.90, meaning it is acidic. This was further confirmed by the
titratable acidity levels. These levels, again, could vary as a result of the spontaneous nature of fermentation. However, the mean pH level identified by Bahiru, Mehari & Ashenafi (2001) was significantly higher than other alcoholic beverages such as Korean honey wine, Nigerian oil-palm wine and African mango juice wine. == See also ==