How gelatin capsules are made

Hard capsules are made by dipping metal pins into warm gelatin, like candle-making in miniature.

stations: 5
things upstream: 20
raw sources: 11
steps from the ground: 5

The short version

Gelatin capsules are made from gelatin dissolved in water, with glycerin or sorbitol added to soften them. Hard capsules come from dipping metal pins in the gelatin solution, rotating them, drying, stripping, trimming and joining two halves. Softgels are formed and filled in one step on a rotary die.

Dissolve the gelatin

Gelatin, made from the collagen of animal skin or bone, is dissolved in water. Plasticizers such as glycerin or sorbitol, colorings and preservatives may be added.

Goes in
Gelatin Glycerin Water
Dip the pins

For hard capsules, metal pins are dipped into the gelatin solution. The pins are rotated as the gelatin sets on them in a thin film.
Dry and strip

The coated pins pass through drying, then the dried shells are stripped off and trimmed to length. The two parts are a smaller body and a larger cap.
Fill the body

The body is filled with dry powder or small pellets by a capsule filling machine. Fill weight is checked in real time.
Join the halves

The cap is pressed on over the filled body to close the capsule. Softgels skip the pins, because a rotary die forms, fills and seals them in one step.

End of the lineGelatin capsule

Worth repeating

The two-piece telescoping gelatin capsule was patented by James Murdoch of London in 1847.
Mothes and Dublanc patented a single-piece sealed gelatin capsule in 1833, filling each one by medicine dropper.
Vegetable capsules made from cellulose were introduced in 1989, though gelatin is still cheaper.