The collagen of squid and octopus is more cross-linked thanfish collagen, so these molluscs require moreprolonged heating at 180ºF/80ºC to give upmuch of their gelatin. Most cooks recom-mend cooking fish stocks for less than anhour so as to avoid making the stock cloudyand chalky with calcium salts from the dis-integrating bones. Another reason for shortand gentle extractions is that fish gelatinsare relatively fragile and more readily breakdown into small pieces when cooked. Andbecause they associate more loosely witheach other, they form delicate gels that meltfar below mouth temperature, at 70ºF/20ºCand lower.