The drying of seaweeds and other plants. IV. —Through‐circulation drying of chondrus crispus in a semi‐continuous dryer

Experiments on the through‐circulation drying of the red alga known as Irish moss ( Chondrus crispus ) have been conducted with a semi‐continuous dryer of original design on a semi‐commercial scale to determine optimum conditions. For fresh weed with an initial content of 78% moisture the feasible load was approximately 4.5 lb./sq. ft./tray with flow of air up to 80 lb. of dry air/min./sq. ft. At temperatures from 120° to 200° F, heat consumptions of 1200–2000 B.Th.U./lb. of water evaporated were recorded. It is possible to operate at a heat consumption of <1800 B.Th.U./lb. of water evaporated with high output. the final moisture content of the product varied between 11 and 18%. the percentage of carrageenin extractable with a hot dilute solution of sodium acetate fell from 54 to ˜43% in the process of drying. While there was some indication that degradation occurred at 155° F or over, many runs showed little change in physical properties at temperatures up to 200° F. Similar measurements of the viscosity and gel strength of dry commercial carrageenin exposed to temperatures of 158–240° F for intervals up to 30 h. indicated a slow degradation which became appreciable only if over 190° F for more than 10 h.