It's to take away the taste of the vodka.
VASILI
[laughing]
I lift my hat to you.
PIKE
You never worked on a farm in your own country, Doc?
VASILI
That has been denied me.
PIKE
I expect so. Talk about things to drink! Harvest-time, and the women folks coming out from the house with a two-gallon jug of ice-cold buttermilk!