I have used both bi-carb and carb... as well as pure natural Mediterranean sea salts.
After running my first run potato vodka through my 2" dia 4 foot Reflux column with a 3:1 reflux ratio making careful and conservative hearts cut [to blend back with neutrals from the next stage...] I add the bi-carb or carb and let it rest a week to 10 days, shaking, then aerating 10-15 minutes once per day... 1 hour before the final spirit run, I add the sea salt as well... in the end, after a second 3:1 reflux spirit run, I end up with a nearly perfect crisp clean neutral, with incredibly low amount of heads and tails...
just a surprising amount of hearts, considering the amount of hearts already taken from my first run... I then blend the two and age on a lump of homemade Birch Charcoal [not activated]. After only one month, I am left with a crystal clear premium potato vodka, with rich velvety mouth feel, delicately sweet and lightly floral nose, virtually no after taste or bite... and even after killing a liter between two old friends... no hangovers... ever!!!
Using this technique, I have
been able to salvage nice neutrals from the really stinky rum tails [not oils... just the small stinky part the real Artisan Experts (not the commercial boys though) discard, just after hearts, just before the rum oils]... this stuff is great for alcoholic fruits, punch bowls, Marinating meats, making extracts, or stimulated flavored commercial spirits... you know, the cocktail stile stuff... so many good uses.
I don't discard one drop of alcohol that I make... even my Methanol has purpose... windshield washer fluid.
Cheers!
Does it really matter where it comes from or only that it is; knowing what to do with it is the only thing that matters. Too many folks tend to lose track of what is important. Does it work or not? Now there's an intelligent question. Words to live by...