Balwan is a special roasted rock salt used by some Jains to provide a very small amount of salty taste during Ayambil. In many Ayambil practices, salt is completely avoided, but in certain traditions a tiny, roasted salt (Balwan) may be allowed to satisfy a minimal salt flavor without breaking the vow of taste-control. The use of Balwan and how much salt is permissible vary by Digambar vs. Shwetambar customs and local maryada. ( jainsite.com)

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