The raw materials that Baijiu is made from include sorghum, wheat, rice, sticky rice, and corn. Different Baijius are made from one or another of these materials in varying amounts depending on the Baijiu. Since Baijius are mixed and blended during the production process, it is therefore the case that many Baijius have multiple raw materials from which they originate. In other words, Baijiu is not made from just sorghum or just wheat. It is a blend.
For example, Moutai — arguably the most highly regarded Baijiu available — is made from 50% sorghum and 50% wheat. Another highly regarded Baijiu called Luzhou Laojiao is made from 60% sorghum, 20% rice, and 20% wheat. Thus, not only are Baijius a blend of these raw materials, but each Baijiu is its own proprietary blend. This results in Baijius with markedly different tastes.
As you can see, the raw materials from which Baijiu is made vary depending on the specific Baijiu in question. This is why even experienced Baijiu drinkers are not necessarily authorities on Baijiu. In other words, there is always another Baijiu that a person has not yet tried that tastes very different from the Baijius he or she has tried. Therefore, if you really want to get to know Baijiu, it is a good idea to try many different Baijius, not just one.