To make Vestal potato vodka they must first wash the potatoes and then boil them under pressure so that you finish up with a thick liquid. They ferment this for several days until they have 5-8 per cent of alcohol by volume. This they distil.
Alcohol becomes a vapor at a lower temperature than water so they caputure these vapors and concentrate them until they have 90 per cent plus alcohol. Add water and you have vodka the way they make it (although not as defined by the EU).
Their "vodkas" have about 100 grams of methanol per hectolitre and the EU defines a vodka as a spirit with up to 10 grams of methanol per hectolitre. However Cognacs can have up to 200 grams and Grappa up to 1,000 grams.
So this is not about your health.Its about producing something that is clinically pure but tasteless and odorless. The way you get to 10 grams of methanol is to rectify (essentially redistil) three, four or five times.
That removes the ethanol and all the taste. They retain the taste and "spirit of place" by distilling only once. If you do this then every single "vodka" you produce is different because you can't replicate the growing conditions, soils etc. Just like producing wine in fact."