Bloom strength explained: choosing the right gelatin grade for capsules

What bloom values mean, which grades suit hard capsules vs. softgels, and how to read a gelatin Certificate of Analysis.

Bloom strength is the single most important number on a gelatin specification — and one of the most misunderstood. It measures gel rigidity: the force, in grams, required to depress a standardized plunger into a gel prepared under controlled conditions.

What the numbers mean

Commercial gelatin ranges roughly from 50 to 300 bloom. Hard capsule shells typically require 200–280g for mechanical strength and clean separation. Softgels run 150–200g for flexibility. Confectionery varies: a firm gummy might use 220–260g, a tender marshmallow much less. Higher bloom generally means higher price per kilogram — but also lower usage rates, so cost-per-unit often converges.

Reading a COA critically

A Certificate of Analysis should state the tested bloom value for the specific batch, the testing method, and the laboratory. Watch for datasheets that quote a bloom range without a per-batch tested value — a range is a marketing document, not a quality record. Also check viscosity, moisture, and microbial results: bloom is necessary but not sufficient.

Matching grade to process

The right grade depends on your equipment and recipe as much as the end product. Dip-molding capsule lines, rotary softgel encapsulation, and confectionery depositors each have their own viscosity and setting-behavior requirements. The practical shortcut: send your current specification to a competent supplier and require them to match it with laboratory evidence.