"Pure grain solid-state fermented liquor" is a unique brewing method in China. Its main feature is that pure grain (such as rice and sorghum) is used for solid-state fermentation and distillation.

Here are some signs you can find on the bottle label:

1. Alcohol: This is one of the basic properties of wine, usually expressed as a percentage. In China, the alcohol content of liquor is usually between 40% and 60%.

2. Raw materials: check whether the raw materials of the product are clearly marked as pure grain.

3. Production process: check whether solid-state fermentation is indicated. Generally speaking, if a wine adopts solid-state fermentation technology, it will be clearly written on the label.

4. Origin: Some areas are famous for their history and craftsmanship, such as Wuliangye in Sichuan and Maotai in Guizhou.

5. Brand and trademark: Well-known brands of pure grain solid-state fermented liquor are usually clearly marked on the label.

6. Certification marks: Some wines may have some certification marks, such as "green food" and "organic products", which can be used as a reference.

These are general suggestions. The specific logo may be slightly different due to different brands, products and regions. Therefore, the best way is to ask a professional salesperson or someone who has a deep understanding of wine when buying.