What was the specific vow Cholkar made, and why did he give up sugar?

As recounted in Chapter 15, Cholkar's livelihood depended on passing an important examination. In his plea for divine assistance, he made a firm vow to Sai Baba that if he passed, he would present himself at Baba's feet in Shirdi and distribute sugar candy in His name. Although his wish was granted and he passed the exam, Cholkar was too poor to afford the journey immediately. Feeling troubled by the delay in fulfilling his promise, he undertook a personal penance: he completely avoided sugar, considering it an inedible substance, until he could complete his pilgrimage to Shirdi. This act of self-denial, which included drinking his tea unsweetened, was his way of maintaining his commitment to Baba despite the delay.