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514:, most rendering installations used the dry process. In the 1960s, continuous dry processes were introduced, one using a variation of the conventional dry cooker and the other making use of a mincing and evaporation process to dry the material and yield the fat. In the 1980s, high energy costs popularized the various "wet" continuous processes. These processes were more energy efficient and allowed the re-use of process vapours to pre-heat or dry the materials during the process.
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367:. The first stage separates the liquid water and fat mixture from the solids. The second stage further separates the fat from the water. The solids may be used in food products, pet foods, etc., depending on the original materials. The separated fat may be used in food products, or if in surplus, may be diverted to soap making operations. Most edible rendering is done by meat packing or processing companies.
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vessel to drive off the moisture and simultaneously release the fat from the fat cells. The material is first ground, then heated to release the fat and drive off the moisture, percolated to drain off the free fat, and then more fat is pressed out of the solids, which at this stage are called "cracklings" or "dry-rendered tankage". The cracklings are further ground to make meat and
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materials. The material is heated with added steam and then pressed to remove a water-fat mixture that is then separated into fat, water, and fine solids by stages of centrifuging and/or evaporation. The solids from the press are dried and then ground into meat and bone meal. Most independent renderers process only inedible material.
521:, synthetic detergents arrived, which displaced soaps in domestic and industrial washing. In the early 1950s, over half of the inedible fat market vanished. Diversion in these materials into animal feeds soon replaced the lost soap market and eventually became the single largest use for inedible fats.
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A further development came in the 19th century with the use of steam digesters: a tank used as a pressure cooker where steam was injected into the material being rendered. This process is a wet rendering process called "tanking" and was used for edible and inedible products, although better grades of
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Usually, materials used as raw materials in the rendering process are susceptible to spoilage. However, after rendering, the materials are much more resistant to spoiling. This is due to the application of heat either through cooking in the wet rendering process or the extraction of fluid in the dry
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meat industry in the United States—with its concentration in one geographic area—because it allowed the economic disposal of byproducts which would otherwise overwhelm the environment in that area. At first, small companies that sprang up near the packers did the rendering. Later the packers entered
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A variation on a dry process involves finely chopping the material, fluidizing it with hot fat, and then evaporating the mixture in one or more evaporator stages. Some inedible rendering is done using a wet process, which is generally a continuous process similar in some ways to that used for edible
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for use in food products. Edible rendering is generally carried out in a continuous process at low temperature (less than the boiling point of water). The process usually consists of finely chopping the edible fat materials (generally fat trimmings from meat cuts), heating them with or without added
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Materials that for aesthetic or sanitary reasons are not suitable for human food are the feedstocks for inedible rendering processes. Much of the inedible raw material is rendered using the "dry" method. This may be a batch or a continuous process in which the material is heated in a steam-jacketed
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would otherwise be a major disposal problem. As an example, the United States annually recycles more than 21 million metric tons of highly perishable and noxious organic matter. In 2004, U.S. industry produced over 8 million metric tons of products, of which 1.6 million metric tons were exported.
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Innovations came rapidly in the 20th century. Some of these were the uses for rendered products, and others were the rendering methods. In the 1920s, a batch dry rendering process was invented; the material was cooked in horizontal steam-jacketed cylinders (similar to the fertilizer dryers of the
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The rendering industry is one of the oldest recycling industries, and made possible the development of a large food industry. The industry takes what would otherwise be waste materials and makes useful products such as fuels, soaps, rubber, plastics, etc. At the same time, rendering reduces what
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The widespread use of "boxed beef", where the beef was cut into consumer portions at packing plants rather than local butcher shops and markets, meant that fat and meat scraps for renderers stayed at the packing plants and were rendered there by packer renderers, rather than by the independent
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edible products were made using the open kettle process. After the material is tanked, the free fat is run off, the remaining water ("tank water") run into a separate vat, and the solids removed and dried by pressing and steam-drying in a jacketed vessel. The tank water was either run into a
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over an open fire. This type of rendering is still done on farms to make lard (pork fat) for food purposes. With the development of steam boilers, it was possible to use steam-jacketed kettles to make a higher grade product, and reduce fire danger. From at least 1896,
261:. Rendering can be carried out on an industrial, farm, or kitchen scale. It can also be applied to non-animal products that are rendered down to pulp. The rendering process simultaneously dries the material and separates the fat from the
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day). Advantages claimed for the dry process were economy of energy, better protein yield, faster processing, and fewer noxious odors. Over the years, the wet "tanking" process was replaced with the dry process. By the end of
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by-products, which in turn allowed the development of a massive industrial-scale meat industry that made food more economical for the consumer. Rendering has been carried out for many centuries, primarily for
502:(1906), an exposé on the Chicago meat processing industry which created public outrage. His work helped the passage of the Pure Food and Drug Act of 1907 which paved the way for the creation of the
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Yellow grease is made by packers. All the refuse materials of the packing houses go into the yellow grease tank, together with any hogs which may die on the packers' hands.
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The processing plant may be operated by an independent company that buys input material from suppliers, or by a packing plant that produces the material in-house.
297:, as well as entire carcasses of animals condemned at slaughterhouses and those that have died on farms, in transit, etc. The most common animal sources are
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were among the early pioneers of the U.S. rendering industry, with their personal backing and/or direct participation in the rendering industry.
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Whether the end products are used as human or animal food depends on the quality of input material and the processing methods and equipment.
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The rejection of animal fats by diet-conscious consumers led to a surplus of edible fats, and the resultant diversion into soapmaking and
568:(mad-cow disease, BSE), which is also fatal to humans. Early in the 21st century, most countries tightened regulations to prevent this.
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rendering process. The fat obtained can be used as low-cost raw material in making grease, animal feed, soap, candles,
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into more useful materials, or, more narrowly, to the rendering of whole animal fatty tissue into purified fats like
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In wet processing, either boiling water or steam is added to the material, separating fat into a floating phase.
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has referred to lower-quality grades of tallow (cow or sheep fat) from animal rendering plants.
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The development of rendering was primarily responsible for the profitable utilization of
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Meat and bone meal in animal feed was one route for the late-20th century spread of
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Edible rendering processes are basically meat processing operations and produce
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Rendering may be done either in discrete batches or in a continuous process.
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into stable, usable materials. Rendering can refer to any processing of
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North
American Rendering: The Source of Essential High Quality Products
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rolling industry, providing lubrication when compressing steel sheets.
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In dry processing, fat is released by dehydrating the raw material.
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In animal products, the majority of tissue processed comes from
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and home cooks. In the kitchen, rendering is used to transform
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Essential
Rendering: All About The Animal By-Products Industry
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Rendering of fats is also carried out on a kitchen scale by
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A Practical
Treatise on Animal and Vegetable Fats and Oils
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The pressure tank made possible the development of the
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321:The rendering process varies in a number of ways:
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709:(April 2005), National Renderer's Association.
339:The temperature range used may be high or low.
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445:making. The earliest rendering was done in a
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53:Learn how and when to remove these messages
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748:Franco, Don and Swanson, Winfield (1996).
371:Rendering processes for inedible products
230:Learn how and when to remove this message
212:Learn how and when to remove this message
150:Learn how and when to remove this message
739:By-Products of the Meat-Packing Industry
245:is a process that converts waste animal
175:This article includes a list of general
673:United States Department of Agriculture
470:. The solids were used for fertilizer.
350:Rendering processes for edible products
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727:. National Renderer's Association.
718:. National Renderer's Association.
181:it lacks sufficient corresponding
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732:Rendering, The Invisible Industry
622:Brannt, William Theodore (1896).
466:or protein concentrate to add to
34:This article has multiple issues.
16:Conversion of waste animal tissue
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42:or discuss these issues on the
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462:or it was evaporated to make
628:. H. C. Baird. p. 110.
536:Advantages and disadvantages
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743:University of Chicago Press
642:Ellin, Abby (Sep 3, 2012).
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1305:List of cooking appliances
797:List of cooking techniques
695:Lyman, Howard, F. (1998).
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880:Grilling (charbroiling)
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196:more precise citations.
885:Roasting (traditional)
750:The Original Recyclers
365:centrifugal separation
752:, APPI, FPRF and NRA.
525:rendering companies.
1424:Industrial processes
737:Young, H.H. (1927).
701:Simon & Schuster
84:improve this article
293:tissue, bones, and
1414:Cooking techniques
1182:Stir frying (chao)
734:, Aero Publishers.
690:General references
317:Process variations
269:, yielding a fat
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1249:Burying in ground
1142:Carryover cooking
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1409:Cooking fats
1191:Device-based
1135:Mixed medium
988:Slow cooking
818:Dry roasting
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676:. Retrieved
672:
669:"FAQ on BSE"
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651:. Retrieved
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512:World War II
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82:Please help
77:verification
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36:Please help
33:
1390:WikiProject
1330:Food safety
1218:Slow cooker
1203:Microwaving
1096:Stir frying
1081:Deep frying
875:Charbroiler
703:, New York.
194:introducing
1403:Categories
1264:Fermenting
1198:Air frying
1147:Barbecuing
1086:Pan frying
1066:Blackening
993:Smothering
937:Parboiling
890:Rotisserie
837:Convection
811:Conduction
789:techniques
697:Mad Cowboy
678:2017-01-28
653:29 January
604:References
553:industry.
499:The Jungle
468:fertilizer
358:or edible
177:references
110:newspapers
39:improve it
1172:Fricassee
1162:Deglazing
1054:High heat
1047:Fat-based
1024:Sous-vide
983:Simmering
947:Reduction
932:Decoction
922:Blanching
915:High heat
868:Radiation
598:Whale oil
547:biodiesel
416:fat into
378:bone meal
271:commodity
243:Rendering
45:talk page
1382:Cookbook
1366:Category
1298:See also
1274:Pickling
1232:Non-heat
1152:Braising
1122:Sweating
1110:Low heat
1101:Sautéing
1071:Browning
1034:Steaming
998:Steeping
978:Poaching
973:Infusion
968:Creaming
963:Coddling
956:Low heat
942:Shocking
895:Toasting
859:Barbecue
648:ABC News
593:Flensing
572:See also
551:chemical
422:schmaltz
1374:Commons
1289:Souring
1284:Salting
1269:Juicing
1244:Brining
1061:Basting
1003:Stewing
927:Boiling
854:Smoking
828:Searing
787:Cooking
475:Chicago
428:History
311:poultry
267:protein
190:improve
124:scholar
1259:Drying
1254:Curing
1167:Flambé
1076:Frying
844:Baking
555:Tallow
517:After
496:wrote
486:, and
447:kettle
443:candle
410:tallow
398:butter
360:tallow
309:, and
307:mutton
259:tallow
247:tissue
179:, but
126:
119:
112:
105:
97:
1279:Purée
1239:Aging
559:steel
460:sewer
408:into
400:into
394:chefs
295:offal
291:fatty
131:JSTOR
117:books
655:2014
519:WWII
464:glue
441:and
439:soap
418:lard
414:pork
406:suet
356:lard
303:pork
299:beef
275:meal
265:and
263:bone
255:lard
103:news
908:Wet
804:Dry
504:FDA
257:or
86:by
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482:,
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412:,
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