If you can squeeze juice out of them it will work unless brix is above scale. In my experience it would work on a juicy Black Jack but not on anything like Strawberry Verte after it shrivels up a bit. On a drier fig the brix is above scale, on mine 32, and you can't get juice with normal means. For figs it's really not that useful. But on things like nectarine, pluot, sweet cherry, and the like it's not only interesting but can help adjust culture for sweeter fruit.