Test Conditions: Per ISO 9665 and GMIA
A Bloom test runs on a standard solution under fixed conditions. Per ISO 9665 or GMIA, the conditions are:
- Gelatin solution concentration: 6.67%
- Setting conditions: 10°C ±0.1°C, held for 17 hours
- Probe: ½-inch (12.7 mm) diameter polyester cylindrical probe
- Penetration speed: 4 mm/s, to a depth of 4 mm
- Result unit: g Bloom
Procedure
Pour the gelatin solution into the standard container and hold it at 10°C for 17 hours to set fully. For the test, the probe penetrates the gel 4 mm at 4 mm/s, and the force at that point is the Bloom value.
The setting conditions and penetration depth are both part of the standard. Changing either one means the result can no longer be compared directly against standard values.
Reading the Data: What Bloom Value Means
A higher Bloom value means greater gel strength. It can be used to monitor gelatin quality, concentration and the effect of processing conditions.
The same gelatin at a different concentration will give a different Bloom value. When comparing sources or batches, confirm that the solution concentration and setting conditions are exactly the same.
Frequently Asked Questions
- Why does a Bloom test need a 17-hour set?
- It's the setting condition specified by the ISO 9665 and GMIA standards. Follow it exactly, without shortening or extending it, so the result can be compared against standard values or other labs' data.
- Can pectin gel be measured the same way?
- Pectin gel is usually compared with a puncture test for rupture force and fracturability, but that's not part of the gelatin Bloom procedure. Choose the method that matches the gel type, and record the conditions used.
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