BLANCHERS Blanching techniques and equipment are similar to those used by the anner and freezer, and the process is carried out either by steam or hot water The dehydrator may have to install both types of blancher, as certain regetables will respond better to steam blanching, whereas hot water blanching is preferred in other cases. Steam Blanches These can either be the rotary thermoscrew-type or a mesh conveyor passing through a steam chest. Where additives require to be used, these have to be sprayed on the vegetables as they leave the blancher. One school of thought in dehydration circles believes that steam blanching inhibit leaching losses but the latter problem has received much scientific attention in recent years, and techniques have been developed in which blancher iquors are buffered to reduce the tendency of soluble solids to dissipate in e course of this process Hot Water blanches These are invariably the rotary screw-type and are somewhat more economical in steam usage. Additives can be introduced directly into the blanching liquor and control is usually more accurate than in the case of additives sprayed after steam blanching An ancillary steam heated tank unit is required to make up a solution of additives(sulphite, citric acid, sodium Pyrophosphate, calcium chloride, sucrose and saline solutions, etc, combinations of which are used with various types of vegetable)and this solution is usually drip fed into the blancher, or circulated by pump, and returned back to the tank, where the required concentration is maintained at a prescribed level Where the level of additives required is high, it is essential to heat the blancher entirely by closed steam coils, rather than by open steam injection, s, by using the latter method, the condensate will dilute the liquor, create a large volume of overflow and generally make control difficult. Open steam injection is sometimes used as a temperature booster but should not be use continuously. Blanching methods vary for each type of vegetable, as will be described later, but it is important, when selecting a blancher, to specify stainless steel construction. With many vegetables, it is customary not to drain the blanching liquor off for several days, and in these circumstances, stainless steel is the most hygienic material to withstand these particular conditions The chemical constituents of blancher water would set up corrosion veryBLANCHERS Blanching techniques and equipment are similar to those used by the canner and freezer, and the process is carried out either by steam or hot water. The dehydrator may have to install both types of blancher, as certain vegetables will respond better to steam blanching, whereas hot water blanching is preferred in other cases. Steam Blanchers These can either be the rotary thermoscrew-type or a mesh conveyor passing through a steam chest. Where additives require to be used, these have to be sprayed on the vegetables as they leave the blancher. One school of thought in dehydration circles believes that steam blanching inhibits leaching losses but the latter problem has received much scientific attention in recent years, and techniques have been developed in which blancher liquors are buffered to reduce the tendency of soluble solids to dissipate in the course of this process. Hot Water Blanchers These are invariably the rotary smw-type and are somewhat more economical in steam usage. Additives can be intmduced directly into the blanching liquor and control is usually more accurate than in the case of additives sprayed after steam blanching. An ancillary steam heated tank unit is required to make up a solution of additives (sulphite, citric acid, sodium pyrophosphate, calcium chloride, sucrose and saline solutions, etc, combinations of which are used with various types of vegetable) and this solution is usually drip fed into the blancher, or circulated by pump, and returned back to the tank, where the required concentration is maintained at a prescribed level. Where the level of additives xquiFed is high, it is essential to heat the blancher entirely by closed steam coils, rather than by open steam injection, as, by using the latter method, the condensate will dilute the liquor, create a large volume of overflow and generally make control difficult. Open steam injection is sometimes used as a temperature booster but should not be used continuously. Blanching methods vary for each type of vegetable, as will be described later, but it is important, when selecting a blancher, to specify stainless steel construction. With many vegetables, it is customary not to drain the blanching liquor off for several days, and in these circumstances, stainless steel is the most hygienic material to withstand these particular conditions. The chemical constituents of blancher water would set up corrosion very 52