Bead" proof` (?).
1.
Among distillers, a certain degree of strength in alcoholic liquor, as formerly ascertained by the floating or sinking of glass globules of different specific gravities thrown into it; now ascertained by more accurate meters.
2.
A degree of strength in alcoholic liquor as shown by beads or small bubbles remaining on its surface, or at the side of the glass, when shaken.
© Webster 1913.