Dutch drop is made from three essential ingredients: licorice extract (from the root of Glycyrrhiza glabra), sugar (sugar, glucose syrup or, in sugar-free drop, polyols) and a binder such as starch, wheat flour, gum arabic or gelatine. Salty drop adds ammonium chloride (salmiak) and sometimes salt; flavoured drops add honey, laurel, anise oil, mint or eucalyptus. The ingredients are cooked into a thick mass, shaped in starch moulds or by extrusion, dried, and often polished with a little wax. The stages below describe the general industrial process; exact recipes, temperatures and times are company know-how and differ by product.
Stage 1 — Licorice extract
Licorice root is harvested mainly in western and central Asia and the Mediterranean. The roots are cleaned, shredded and boiled or steeped in water; the liquid is filtered and evaporated into a thick paste, a hard block or a spray-dried powder. Dutch confectioners buy this extract from specialist suppliers rather than processing roots themselves. Its glycyrrhizin content and flavour vary with origin and grade, which is one reason brands taste different.
Stage 2 — Dissolving
Block or paste extract is dissolved in hot water and filtered so that no woody fibre remains. Powdered extract can be added more directly.
Stage 3 — Mixing
The extract is mixed with sugar and glucose syrup, the binder, and any flavourings and colours. The binder largely determines texture: flour- or starch-based mixes give a firm, short bite; gum arabic gives the harder, glassy texture of traditional lozenges; gelatine gives a softer, more elastic gum. Ammonium chloride and salt are added here for salty drop, or kept back for a surface coating later.
Stage 4 — Cooking
The mixture is cooked to drive off water and gelatinise the starch. English Wikipedia's article on licorice confectionery describes the ingredients being dissolved in water and heated to around 135 °C. Many factories use continuous cookers or vacuum cookers, which remove water at lower temperatures. The cooked mass must reach the right solids content: too wet and the drop stays sticky, too dry and it becomes hard and brittle.
Stage 5 — Shaping: starch moulding or extrusion
Most shaped drop is made by starch moulding on a machine called a mogul. Trays are filled with fine, dry starch powder; a board with plaster or metal shapes is pressed into the starch to leave hollows (a diamond, coin, cat, car); and the hot liquid mass is deposited into them. The starch holds the shape and absorbs moisture. After setting and drying, the pieces are tipped out, the starch is sieved and blown off, and the starch is dried and reused.
Ropes, tubes, bars and laces are made by extrusion: a stiffer mass is pressed through a die and cut to length. Extrusion is fast but limited to shapes with a constant cross-section, so figural shapes are moulded. See drop shapes.
Stage 6 — Drying (stoving)
Moulded drop stays in the starch in warm, climate-controlled drying rooms, typically for a day or more, until it reaches the intended firmness. Hard drop needs longer than soft drop. Drying is often the longest step in the process.
Stage 7 — Finishing
- Glazing: a thin layer of wax or oil (for example beeswax or carnauba wax) gives drop its shine and stops pieces sticking together.
- Salmiak or salt coating: some salty drop is dusted with ammonium chloride powder or salt for an immediate salty hit.
- Sugar or mint coating: pieces can be panned with a sugar or mint shell, as with Venco's Schoolkrijt.
Coatings are applied in rotating pans or drums in which the pieces tumble while the coating is added.
Stage 8 — Packing
Finished drop is weighed and packed, usually in bags, rolls or tins. EU rules require the ingredient list and, where glycyrrhizinic acid exceeds set thresholds, a "contains liquorice" warning (see licorice and health).
Where Dutch drop is made
Most of the big Dutch brands are still produced in the Netherlands. Red Band and Venco (both Cloetta) are made in Roosendaal, Klene belongs to Perfetti Van Melle, and Autodrop is made by Concorp in Irnsum, Friesland; numerous smaller makers produce for specialist shops and supermarket own-label ranges. The licorice extract itself is imported. See Dutch candy brands.