Stuff whole peppers into the preserving bottle. Drop in a teaspoon of dried rosemary, a teaspoon of sea salt, a and a few peppercorns. Pour olive oil into the bottle, filling until about an inch from the top.
Now, put the bottle in a dry, cool and dark place. Once a week give the bottle a shake and after a few weeks, the oil will change to slightly reddish color. It takes about a month to achieve the desirable hotness.