In order to determine the alkalinity in the water-soluble ash, the water-soluble portion of the total ash is titrated in the laboratory using an appropriate amount of acid with an appropriate indicator. The alkalinity value is indicated in milliliters of the hydrochloric acid required for the 100 gram milled dry matter sample, or as a percentage by weight of potassium hydroxide in the milled dry matter sample. The result shows whether alkali carbonates are present in the food, ie, if anything is added to the food.

In the determination of alkalinity in water soluble ash, total ash determination, water soluble ash determination and water insoluble ash determination procedures are applied to the tea sample first. The determination of alkalinity in water soluble ash is carried out by using the filtrate obtained in water soluble ash determination and water insoluble ash determination studies. During the analysis, the filtrate obtained in the water-soluble ash assay is titrated with the adjusted hydrochloric acid solution using the methylorange indicator.

The values ​​obtained from these analyzes are important for determining the physical and chemical criteria in Turkish Food Codex Black Tea Communiqué correctly (Communiqué no: 2015 / 30).

In the aforementioned disclosure, the alkalinity in water-soluble ash in KOH must be the lowest 1 and the highest 3 for black tea, black tea (filter bag), green tea and green tea (filter bag). The value obtained as a result of the analysis performed in the laboratories is compared with this criterion and reported.

Within the scope of physical analyzes, determination of water soluble ash in black tea is also carried out in authorized laboratories. During these studies, the standards published by national and international organizations are followed. In the determination of alkalinity of water soluble black tea, the following standard is complied with:

• TS 1567 Tea - Determination of alkalinity in water soluble ash