Method of manufacturing tea drink

A method of manufacturing a tea beverage comprising the steps of:

• subjecting tea leaves to extraction to obtain a tea extract and adjusting the pH of the tea extract to the range of 5.0-6.0;
• mixing nitrogen into the pH-adjusted tea extract to decrease a dissolved oxygen concentration of the tea extract;
• applying a negative pressure of between 0.01 MPa and 1 MPa to the tea extract into which nitrogen is mixed;
• after applying said negative pressure, exposing the tea extract to a pressure of not higher than atmospheric pressure for a period of 30 seconds to 20 minutes to remove oxygen and nitrogen in the tea extract;
• adjusting the pH of the tea extract to the range of 5.5-6.5 during or subsequent to said step of exposing the tea extract to the pressure;
• and
• producing the tea beverage comprising the tea extract.