Could you describe the miracle of the grapes in detail, including the reactions of the people present?

Absolutely. The miracle is recounted in Chapter 35. When Kaka brought grapes with seeds as an offering, Baba began to distribute them. Boss Dharamsee, a visitor, was troubled as he disliked this variety. He even thought that if Baba were a true saint, he would know this. In response to this thought, Baba gave him even more grapes. Commanded by Baba to 'Eat them up,' Dharamsee complied and was stunned to find they were completely seedless. His reaction was one of utter amazement; his 'ego dropped away, and love for the saint was born.' To confirm what happened, he asked another devotee, Tarkhad, about his grapes. Tarkhad confirmed his had seeds, which left Dharamsee 'extremely surprised in his heart.'