The yogurt starter is fully natural. It does not contain sucrose. Actually it doesn't contain anything else but two bacteria strains. And it contains a lot of it, more precisely billions and billions of the right kind of bacteria, compared to the store-brand yogurts and most of the other yogurt starters which only contain bacteria in the millions. This is also the reason why it always works — your yogurt will never be runny when you make it with bacillus bulgaricus.