Low temperature cooking
The Low-temperature cooking or low temperature method is kind of meat in the oven o. Ä. To cook . The oven temperature is around 80 ° C , the core temperature of the meat is around 55–70 ° C. The low temperature method takes the place of roasting , but largely avoids drying out and possible toughening - the meat remains juicy and pink. The cooking time is much longer than at higher temperatures, but it does not require supervision and it can be significantly extended without any loss of quality.
Since the temperature is not sufficient for browning reactions such as the Maillard reaction and caramelization , the low-temperature method is usually combined with searing the meat, during which the desired roasting substances are formed.
The low-temperature method is suitable both for sensitive types of meat such as fillet or roast beef , which are usually briefly fried, and for pieces rich in connective tissue such as veal shank , which are usually braised, as well as poultry and fish .
When cooking meat, two reactions are critical: from 50 ° C to start the contained proteins to denature and enhanced separation of proteins (in particular the fiber protein collagen ) by cooking product contained in the enzymes . From 50 ° C in combination with longer cooking times, the collagen of the firm connective tissue turns into gelatine , which causes meat (especially rich in connective tissue) to become tender. As the temperature rises, the previously bound water is increasingly released, which dries out the meat and makes it harder.
When roasting with oven temperatures of 150 ° C and higher, there is a strong temperature gradient from the outside to the inside. If the core of the piece of meat has reached the ideal temperature, it is already exceeded further outside, which can be recognized by the increasing gray color, which indicates that the proteins have completely coagulated. This is accompanied by a loss of fluid that increases from the inside out. According to the traditional method, a piece of meat is optimally fried if, depending on its type and size, the best combination of temperature and cooking time is adhered to, i.e. the desired core temperature is achieved with as short and as little overheating of the other areas as possible.
With the low-temperature method, this temperature gradient is largely avoided, which is why the size of the food and the exact cooking time play a much smaller role. The desired core temperature is exceeded significantly less, and the fluid remains largely bound in the tissue. In the long cooking time required for the low-temperature method, the connective tissue can be completely broken down into gelatin.
The Federal Center for Nutrition of the Federal Agency for Agriculture and Nutrition recommends a two-minute core temperature of 72 ° C for meat, fish, egg dishes , raw milk and frozen berries for reasons of hygiene . The Federal Office for Consumer Protection and Food Safety recommends that cooked foods reach a core temperature of 70 ° C (no time specified). According to the Bavarian State Ministry for the Environment and Consumer Protection , meat needs a core temperature of at least 70 ° C for cooking, which should be maintained for a period of 10 minutes. The meat changes color from red to gray or brown. However, browning , for example through contact with oxygen or slow thawing, can lead to a brown color inside the meat, which is why the core temperature should be determined with a roasting thermometer .
So that aromatic roasted substances develop, the meat is first briefly browned on all sides until it is golden brown and immediately removed from the fire. Then it is seasoned and cooked in the oven at 60–80 ° C. The food can be left open in the cooking space or covered in order to minimize the loss of liquid on the surface. The order can also be reversed - then the meat cooked in the oven is only seared before serving.
The cooking time depends heavily on the texture and size of the piece of meat. As a rough guide, the following times can be given for some types of meat: fillet is pink and cooked after about an hour, roast beef such as boiled beef after five to six hours , roast goose after eight to nine hours. The cooking times can also be significantly extended. The closer the oven temperature is to the desired core temperature of the food, the less problematic it is to extend the cooking time. There are cooks who use times of 14 to 60 hours at 60 ° C for pieces off the shoulder or hip.
The so-called resting after cooking is not necessary with the low temperature method.
Benjamin Thompson , Earl of Rumford , discovered together with his kitchen assistants that a shoulder of mutton, which remained overnight in an extinguished potato drying box, had reached a perfect degree of doneness. The technique was reinvented in France in the 1960s, but initially mainly used in the industrial production of food. Among other things, the chemist Bruno Goussault and the cook George Pralus (the latter from the Troisgros restaurant ) introduced the process to top gastronomy. An extension of the method is low-temperature cooking in a vacuum bag , known as vacuum cooking.
- Cornelia Schinharl: Tender meat thanks to gentle cooking with the 80 ° C method. Bassermann, Munich 2008, ISBN 978-3-8094-2401-7 .
- Margit Proebst: Tender and juicy at 80 ° C: low temperature cooking. Gräfe and Unzer Verlag, Munich 2006, ISBN 3-8338-0073-9 .
- Portrait of Bruno Goussault on Foodarts.com . Retrieved November 19, 2012.
- Elisa Dominguez-Hernandez, Alvija Salaseviciene, Per Ertbjerg: Low-temperature long-time cooking of meat: Eating quality and underlying mechanisms. In: Meat Science. 143, 2018, pp. 104–113, doi : 10.1016 / j.meatsci.2018.04.032 .
- Federal Center for Nutrition: Preparing food hygienically: Simple rules help. In: bzfe.de. April 13, 2017. Retrieved November 15, 2018 .
- BVL - preparing food. In: bvl.bund.de. Retrieved November 15, 2018 .
- Bavarian State Ministry for the Environment and Consumer Protection: Seven main rules for the hygienic handling of food, Rule 4: Heating
- Nicola J. King (née Turner), Rosemary Whyte: Does It Look Cooked? A Review of Factors That Influence Cooked Meat Color. In: Journal of Food Science. 71, 2006, pp. R31-R40, doi : 10.1111 / j.1750-3841.2006.00029.x .
- Benjamin Thompson: The complete works of Count Rumford (1870), Essays, political, economical, and philosophical, Volume 3 , p. 188. PDF (English) , search term drying potatoes . Retrieved November 19, 2012.