A few words from Hieromonk Platon of New Marcha Monastery in Richfield, Ohio:
In clarifying the Typicon for the Feast of the Lord’s Transfiguration, which is found in the August Menaion, we find a warning which deals with one special kind of fasting.
Namely, the Fathers order that a blessing of fresh grapes be done in the church on the Feast of the Transfiguration of the Lord and as blessed fruit it be distributed to the people and as such that it be used, besides on Transfiguration, also on the following Monday, Wednesday and Friday.
In preparation for consuming this blessed fruit we do not eat fresh grapes from new vines until the feast of the Transfiguration. This goes for those who do not have vineyards as well as those who do.
In the event one KNOWS THIS RULE and willingly does not comply the Fathers order that they not be given any of the blessed grapes nor that they be given grapes at all throughout the month of August.
The meaning of this fast is in awaiting the ripeness of fruit, and in offering it to the Lord for a blessing and in thanksgiving to Him…