In a large pot add the oil on medium/low heat and a minute later add the onions. Sauté for 2-3’ and add the celery, continuing and sautéing for 4-5’. Toss in the garlic and a minute later deglaze with the wine on high heat. Stir for another minute and add the vegetable broth and the saffron. Bring to a boil and add the tomatoes with the orzo, season with the salt and pepper, again bring to a boil and simmer for 6’ aiming for the orzo to be 2/3 cooked.