By Nancy Harmon Jenkins, Special to The Washington Post The fragrance of brand-new olive oil is unmistakable. If you’ve ever experienced it, you’ll recognize it instantly ever after. When the oil is fresh from the press, it’s as intense and all-pervasive as the aroma of white truffles, as penetrating as that of fir balsam, as seductive as the smell of June roses lingering in the nose for days after the blooms themselves have faded. The best time and place to experience that extraordinary perfume in its fullest impact is at the olive mill — the frantoio, as it’s called in Italy — at the moment newly harvested olives are crushed into oil.