Food Drying Equipment – Low-Temperature Drying Equipment for Seafood and Laver

Low-temperature drying vs. high-temperature drying

Food is dried to reduce moisture and lower water activity (Aw), which is the water microorganisms can use. Most bacteria stop growing near Aw 0.9, and molds near 0.7, so dried seafood is usually lowered below those levels to achieve room-temperature storability.

High-temperature drying is fast, but surface moisture evaporates quickly, making the outside harden first in a process called case hardening. When the surface becomes sealed this way, internal moisture cannot escape, leaving the outside dry while the inside remains insufficiently dried, or damaging nutrients, color, and aroma. Cold/hot-air low-temperature drying combines cold air and hot air at or below room temperature so the inside and outside dry evenly, making it suitable for premium dried foods that preserve taste, aroma, texture, and rehydration quality close to the original.

Drying passes through a constant-rate period, when free water on the surface evaporates at a steady speed, and then a falling-rate period, when the drying speed slows as internal moisture diffuses to the surface. For this reason, precise control of airflow, temperature, and time in the finishing stage determines final quality.

Laver and seaweed drying

Laver and seaweed drying is a complex process that continuously handles sauce coating, topping attachment, lamination, and drying. It is a key stage in mass production of seasoned laver and laver snacks.

The coating amount and drying temperature must be kept consistent to achieve uniform texture and color without sogginess.

Choosing drying equipment

Choose a drying method based on raw material, such as seafood, laver, or seaweed; target moisture content; required level of flavor preservation; and hourly throughput. Low-temperature drying is advantageous for premium dried seafood and rehydrated foods, while continuous conveyor types are better for mass production.

Jepid drying equipment includes laver dryers and laver sandwich machines that handle sauce coating, lamination, and drying in one process.