Yeah it was grape juice
And he said unto them, This is my blood of the new testament, which is shed for many. Verily I say unto you, I will drink no more of the fruit of the vine, until that day that I drink it new in the kingdom of God. Mark 14:24-25
And he took the cup, and gave thanks, and said, Take this, and divide [it] among yourselves: For I say unto you, I will not drink of the fruit of the vine, until the kingdom of God shall come. Luke 22:17-18
Leaven was always symbolic of evil and therefore could not have been used to ferment the "fruit of the vine" in the ordinance of the Communion.