Vodka production: Quality testing
Quality starts with the raw materials. Remember the saying? "You can't make a silk purse out of a sow's ear."
Quality testing can start even before the raw material that will make the vodka has been put in the ground as some producers will test the soil for its nutrient levels prior to sowing seeds. Certainly, grain and other ingredients will be tested for quality prior to use. The same will be true of the water and even the bottles.
At every stage of the vodka making process, samples will be taken and tested using chemical analysis such as gas chromatography. However, ultimately human organoleptic testing is the best check of quality and trained tasting panels are almost always used to test batches prior to bottling.
As important as the testing is the recording and identifying of the test batches throughout the process right through to the finished bottle. The small barely visible number printed on the neck of most bottles identifies not only the day and hour when that vodka was bottled, but will often also allow the distiller to trace the batch of grain used to make it.