In the alkalinity analyzes carried out in the laboratories, the alkalinity value in the water-soluble ash is determined, while the amount of hydrochloric acid required for the 100 gram milled test sample or the weight percentage of potassium hydroxide (KOH) in the milled test sample is calculated. In this study, it has been determined whether the alkaline carbonates are present in the tested food product, that is, whether foreign substances are added to the food.

In order to determine the alkalinity in water-soluble ash, the total ash content, water-soluble ash content and water-insoluble ash content of that foodstuff must first be determined. In this way, alkalinity is determined by using the filtrate obtained in the water-soluble ash and water-insoluble ash analyzes.

When determining the water-soluble portion of the total ash, the filtrate obtained is titrated with hydrochloric acid solution using a methylorange indicator.

Determination of alkalinity in ash is done in two ways. First, the alkalinity of the water-soluble ash is calculated on the basis of the 100 gram milled test sample (on a dry matter basis). The alkalinity of the water-soluble ash is then calculated on the basis of dry matter in the milled sample, the percentage by weight of potassium hydroxide (KOH). The arithmetic mean of both calculations is then followed.

According to the Turkish Food Codex Tea Communiqué (Communiqué No: 2015 / 30) issued by the Ministry of Food, Agriculture and Livestock, the amount of alkalinity in water-soluble ash in potassium hydroxide (KOH) must be at least 1,5 and at most 3. This Communiqué specifies the production and processing characteristics of black tea, green tea, black and green tea with added flavor.

Alkalinity determination of water soluble ash in potassium hydroxide (KOH) is carried out in authorized laboratories within the scope of chemical tests. In these studies, the provisions of the mentioned communiqué are taken as basis and the standards published by domestic and foreign organizations and the test methods accepted worldwide are complied with.