Marani Brands Inc. (MRIB)

[zumoney]

Yes, to control alkalinity. To soften taste and stuff...

I don't know how great this source is but it seems quite technical and informative.

See link and quote:

http://www.vodka-tf.com/history_of_vodka/

"The Technical Committee developed and patented on January 31, 1894 the state recipe of vodka – “Moscow Special Vodka”, later dubbed “Monopolistic Vodka”. To control alkalinity and soften taste and odour of the alcohol, the recipe provided that small amounts of sodium bicarbonate and acetic acid should be added. It should be noted that no reliable written evidence of D.I.Mendeleyev’s participation in the work of the Committee or in developing the recipe has not been discovered so far."