The context of your question is unclear. However, you can melt gelatin in acid as well as water so you end up with gelatin in hot (or warm) acid or water depending on what you want. Gelatin will gel below 20 deg C or 68 F even in acid. However, extremely strong acid denatures gelatin and prohibits gelation. This gelatin is considered useless for most purposes as it can be easily washed away.

PE