Bloom

The term bloom refers to the strength of the set gelatin, which is measured by the gelatin manufacturer using a gellometer, invented by a French scientist named Bloom — hence the term. A gellometer is a calibrated rod (like a thermometer) with markings from 50 to 300 bloom; 225 to 250 bloom is the average reading for most set gelatin products. The tool is dropped into the set gelatin from a predetermined height to obtain a reading. Sometimes the word bloom is used to describe the process of softening the gelatin in a cold liquid before it is dissolved. These are two distinct meanings. (The word bloom is also used to describe the grey streaks that appear on improperly tempered chocolate, but that meaning has nothing to do with gelatin.)