Measure ¾ cup warm water and add the remainder of the yeast packet. (about 2 ⅛ tsp) Stir to dissolve the yeast and allow it to rest for 5 minutes.
In the bowl of your stand mixer (or a large bowl if mixing by hand), combine the poolish, yeast, and water mixture, 2 cups whole wheat flour, 1 tablespoon vital wheat gluten, and 1 teaspoon sea salt.
Using a dough hook mix on low speed for 2 minutes. If mixing by hand knead and stir to combine all ingredients.
Knead the dough for about 5 minutes on medium speed, until smooth and elastic. If the dough is too sticky, add a little flour as needed, but avoid adding too much to keep the bread soft.