As part of our May 2019 STEADFAST RANGER v1.48  update, we've added several new consumables to the game, including Birch Bark Tea.
Like Rosehip and Reishi Tea, Birch Bark Tea is a restorative tea made from prepared ingredients found in the world. Birch Bark can be found underneath birch trees, and more abundantly in birch groves.
One of the many birch groves found in The Long Dark.
A piece of Birch Bark.
To prepare Birch Bark Tea:
Ensure you have at least 0.25L of Potable Water and 2 Birch Bark.
Prepare the Birch Bark from the Crafting tab in your inventory.
At a Fire Barrel, Campfire, or Stove with an active fire and sufficient burn time (at least 12 minutes), use a Recycled Can or Cooking Pot to combine the ingredients from the Cooking tab.
Wait until the tea has finished boiling and remove it from the fire.
Preparing Birch Bark from the Crafting tab.
Cooking Birch Bark Tea on a fire.
Drinking Birch Bark Tea will restore a small amount of lost Condition over time. Like Rosehip and Reishi Tea, it also has a Warming benefit when consumed while hot.