Heat a dry skillet over medium heat and toast 1 cup roasted barley, stirring occasionally, until golden brown and fragrant, about 5 minutes.

In a medium saucepan, bring 4 cups water to a rolling boil over high heat, about 5 minutes.

Add the toasted barley to the boiling water and stir briefly to combine.

Reduce heat to low and simmer the mixture for 15 minutes to extract maximum flavor.

Remove from heat and strain the tea through a fine mesh strainer into a pitcher or heatproof container.

If desired, stir in 1-2 tablespoons sweetener (optional) while the tea is still warm until fully dissolved.

Serve the tea hot immediately, or let it cool to room temperature, refrigerate, and serve over ice for a refreshing cold beverage.

Store any leftover tea in a sealed container in the refrigerator for up to one week.