The “vinegar” that Boaz offered Ruth was probably a drink similar to wine that had been fermented longer than usual until it developed a sour taste. This is the same type of drink that was offered to Jesus on the cross (Matthew 27:34, 48).

The parched corn or toasted grain eating by Ruth consisted of whole grains of roasted wheat or barley. Roasted in a pan or over an open fire, it served as a good bread substitute. Regular bread was made from wheat or barley that had been ground into a fine flour.

EATING ROASTED GRAIN 

1.  Jesse sent roasted grain and other food to his sons who were serving in King Saul’s army (1 Sameul 17:17).
2.  The Israelites ate roasted grain in Canaan soon after occupying the land. This brought an end to God’s provision of manna, which they had eaten in the wilderness (Joshua 5:11-12).
3.  Abigail brought roasted grain, along with other food, to David’s hungry warriors after her stingly husband, Nabal, refused to give them provisions (1 Samuel 25:10-11, 18).
4.  King David’s supporters brought roasted grain and other food to him and his asides after they were forced to flee Jerusalem during Absalom’s rebellion (2 Samuel 17:27-29).

RUTH 2:14 – Boaz said unto her [Ruth], At mealtime come thou hither, and eat of the bread, and dip thy morsel in the vinger [wine vinegar, NIV]. And she sat beside the reapers: and he reached [offered, NIV] her parched corn [roasted grain, NIV], and she did eat.