The quality of being congealable; the degree to which something is capable of congealing.
From 'congealable' + '-ness,' a suffix that nominalized adjectives into abstract nouns describing qualities or states.
This ultra-precise word would appear in technical food science or chemistry texts, but it's so rare that even spell-checkers might flag it as wrong.
Complete word intelligence in one call. Free tier — 50 lookups/day.