No, colostrum is not sweet. It is mostly fats and proteins, with little lactose. 

30-40 hours after the placenta is delivered, the drop in progesterone triggers lactogenesis II, and lactose synthesis in the mammary gland rapidly accelerates. The increased lactose in the secretion draws fluid into the alveolar cells and lumen, and the result is what we refer to as "milk." "Mature milk" is basically colostrum plus lactose and water. (It's far more complex than that, of course!).  

Linda Smith, BSE, FACCE, IBCLC - enjoying beautiful fall weather in Dayton OH today.