Comment by devilsabvocate

Just in case you wanted to optimize your extraction technique: "The optimal conditions for extracting theanine from green tea using water were found to be extraction at 80 °C for 30 min with a water-to-tea ratio of 20:1 mL/g and a tea particle size of 0.5-1 mm." https://pubmed.ncbi.nlm.nih.gov/21735551/