In an antemortem burn which is NOT true -
In ante-mortem burning, bullae are albuminous, i.e. contain albumin.

Postmortem findings in death due to burn
1) Specific signs (which indicate antemortem burning) :
(i) Soot and Carbon particles in respiratory passages,
(ii) Increased carboxy hemoglobin (>5%) in blood,
(iii) Signs of vital reaction,
(iv) Signs of inflammation,
(v) Redline of demarcation,
(vi) True blister (vesicle) containing protein (albumin) and chloride,
(vii) Increased enzyme and sulfhydryl (-SH). group,
(viii) Increased serotonin and histamine, and 
(ix) Signs of healing and repair.
2) Non-specific signs (may also occur in postmortem burning) :
(i) Pugilistic attitude,
(ii) Heat hematoma,
(iii) Heat fracture,
(iv) Heat ruptures.
Line of redness
Increase in enzymes
Vesicle formation
Non-albuminous bulla