For the Douglas Fir milk: Rinse the branches under hot water to remove any undesirable elements.
Chop the branches coarsely.
Bring the milk to a simmer and then stir in the chopped branches. Turn off the heat and cover the pot with plastic wrap. Let steep for about 30 minutes or until the milk is fully infused with the Douglas fir.
Strain the milk through a fine-mesh sieve. Cool over an ice water bath.
Weigh out the necessary amount for the ice cream base.