Every morning I bring with me a small PETE (from some searches it seems to be the same as PET plastic) bottle (an ex coke bottle) containing hot tea.   Is it safe to store hot liquids, especially, tea in this type of container? Is possible, under these conditions, that the bottle releases some harmful substances?   Thanks in advance.  
A couple of things will help give you smaller holes:   Keep the hydration reasonably low (say, 60% with American-style bread flour). Use some oil or butter. Try 10% (baker's ratio). Knead very well, something like 10–15 minutes in a stand mixer. After the first rise, normally you try to be gentle, and not press out all the air. Don't. Instead, press it out. Bake in a moderate (say, 350°F) oven. You don't particularly want much oven spring here.   For even finer texture, part way through the second rise, you can press it out again, and let it start a third rise (but not to double).  Also, adding some whole wheat or rye flour will give a denser crumb. With different flavor, too, of course. 