First of all, if you want to distinguish between grain wine and blended wine, you can start with the implementation standard of wine. The executive standard for pure alcohol blended liquor is GB T20821, while the executive standard for solid-liquid combined liquor is GB T20822, and the executive standard for pure grain wine is GB T10781. For each fragrance type, there are also specific labels, such as the strong fragrance type is GB T107811. The fragrance type is GB T107812。
Secondly, observing the outer packaging and bottle of wine is also a way to distinguish grain wine from blended wine. The outer packaging box of the fake wine is old, the bottle body has obvious signs of wear, and the clarity of the fake wine trademark is poor, the color is not correct, and there is no anti-counterfeiting logo. The sealing process of real wine is more, with anti-counterfeiting balls and plastic covers, while the sealing of fake wine is relatively simple and not standardized.
In addition, seeing if there is turbidity is also a way to judge grain wine and blended wine. If it is a transparent glass bottle, look into the sunlight to see if there are suspended solids, cloud-like small things or sediment. Real liquor is colorless and transparent, and fake liquor will have suspended matter or sediment. The pure grain wine is viscous and crystal clear, and it can be drawn into a thread when pouring the wine into the glass. 
Finally, you can verify it with some experiments. For example, if you put a drop of oil in the wine, if the oil spreads out evenly and sinks, it means that the quality of the wine is good. The molecules of pure grain wine hold each other very tightly, and the body of the wine will not overflow even if it is a little higher than the rim of the glass. You can also pour the liquor into the bottle and shake it up and down, if the bubbles are dense and small, and the duration reaches more than 7-8 seconds, it is pure grain liquor, and the longer the bubble lasts, the better the quality of the liquor. It is also possible to drop a drop of cooking oil into the wine, and if the oil spreads irregularly and the sinking rate changes significantly, it is an inferior wine.