No. Ristretto is a "short shot" (30 ml from a double basket) of a highly concentrated espresso. There is no milk to reduce acidity. The exact amount of ground coffee is used, but a finer grind is used (also in 20 to 30 seconds) and half the water is used. A normal short shot might look like a ristretto, but in reality, it would only be a weaker, more diluted, shot. The opposite of a ristretto (which means in Italian, "shortened, narrow") is a lungo ("long"), which is a double shot. The French call a ristretto a café serré.