How did Sai Baba reveal to Cholkar that he knew about his secret renunciation of sugar?

Sai Baba's revelation of his knowledge came at a perfectly orchestrated moment, as detailed in Chapter 15. After Cholkar had his darshan and fulfilled his vow by distributing sugar, he was staying as a guest with Mr. Jog. As Cholkar and Jog were about to leave the mosque, Baba spoke directly to Jog, saying, "Give him cups of tea, well-filled with sugar." This command was deeply meaningful because Baba himself did not drink tea, and more importantly, it directly addressed Cholkar's secret sacrifice. Hearing these words, Cholkar was amazed, and tears of joy filled his eyes as he realized Baba was giving him a "full hint" that his vow and his private penance were both known and accepted.