During Parshyun (Paryushan), which is one of the most significant festivals in Jainism, followers observe heightened spiritual discipline, including stricter dietary rules. The primary focus is on self-purification, non-violence (ahimsa), and minimizing harm to any living beings.

Coffee is generally avoided by many devout Jains during Paryushan for several reasons:

1. Fermentation: Coffee, like tea, can involve fermentation in its preparation, which is discouraged during Paryushan as fermented foods may contain more microorganisms, increasing the potential for himsa (harm to living beings).
2. Stimulating Substances: Jain principles encourage control over passions and the senses. Stimulants like coffee can be seen as contrary to this principle.
3. Fasting and Simplicity: Many Jains fast or simplify their diet during Paryushan to cultivate self-control and detachment, often avoiding not just coffee but also other rich or processed foods.

However, practices can vary depending on individual, family, or sect traditions (Shwetambar, Digambar, etc.). Some may abstain strictly, while others may allow it in moderation if it is prepared in a way that minimizes harm.

In summary: It is advisable to avoid consuming coffee during Parshyun (Paryushan) in keeping with the spirit of increased austerity and non-violence. Always consult your family elders or local Jain community guidelines for specific practices.