Steaming:
Steaming is a method of cooking using steam. It is a preferred cooking method for health conscious individuals because no cooking oil is needed, thus resulting in a lower fat content. Steaming also results in a more nutritious food than boiling because fewer nutrients are destroyed or leached away into the water (which is usually discarded). It is also easier to avoid burning food when steaming. Steaming works by first boiling water, causing it to evaporate into steam; the steam then carries heat to the food, thus cooking the food. Such cooking is most often done by placing the food into a steamer, which is a typically a circular container made of metal or bamboo. The steamer usually has a lid that is placed on the top of the container during cooking, to allow the steam to cook the food.
Toasting:
To heat and brown (bread, for example) by placing in a toaster or an oven or close to a fire. Cooking to a brown crispiness over a fire or on a grill; "proper toasting should brown both sides of a piece of bread". This is done using a toaster like the one below.
Slow Cooking:
Raw food, and a liquid which is predominantly water, such as water, wine, stock, (but not oil without water), are placed in the slow cooker. Some recipes work best if the liquid which is added to the other ingredients has been already heated to boiling point, for example, in a kettle. Recipes intended for other cooking methods must be modified for slow cookers. Often water must be decreased, as cooking at higher temperatures requires enough liquid to allow for evaporation. Some slow cookers are supplied with recipe booklets; many slow cooker recipes are to be found in cookbooks and on the internet. A small number of cookbooks seek to make complete dishes in a slow cooker using fewer than five ingredients, while others treat the slow cooker as a serious piece of culinary equipment capable of producing gourmet meals. With some experience, timing and recipe adjustments can be successfully made for many recipes not originally intended for these cookers. The long, moist nature of the cooking method gives good results even with cheaper (and tougher) cuts of meat in fact, cheaper cuts often have more flavour.
Methods Of Heat Transfers:
Radiation:
Radiation is the transfer of heat through electromagnetic radiation. Hot or cold, all objects radiate energy at a rate equal to their emissivity times the rate at which energy would radiate from them if they were a black body. No medium is necessary for radiation to occur; radiation works even in and through a perfect vacuum. The energy from the Sun travels through the vacuum of space before warming the earth. Also, the only way that energy can leave earth is by being radiated to space. Both reflectivity and emissivity of all bodies is wavelength dependent. The temperature determines the wavelength distribution of the electromagnetic radiation as limited in intensity by Plank’s law of black-body radiation. For any body the reflectivity depends on the wavelength distribution of incoming electromagnetic radiation and therefore the temperature of the source of the radiation while the emissivity depends on the wave length distribution and therefore the temperature of the body itself.
Conduction:
Conduction is the transfer of thermal energy from a region of higher temperature to a region of lower temperature through direct molecular communication within a medium or between mediums in direct physical contact without a flow of the material medium. The transfer of energy could be primarily by elastic impact as in fluids or by free electron diffusion as predominant in metals or phonon vibration as predominant in insulators. In other words, heat is transferred by conduction when adjacent atoms vibrate against one another, or as electrons move from atom to atom. Conduction is greater in solids, where atoms are in constant contact. In liquids (except liquid metals) and gases, the molecules are usually further apart, giving a lower chance of molecules colliding and passing on thermal energy.
Heat conduction is directly analogous to diffusion of particles into a fluid, in the situation where there are no fluid currents. This type of heat diffusion differs from mass diffusion in behaviour, only inasmuch as it can occur in solids, whereas mass diffusion is limited to fluids.
Convection:
Convection is a combination of conduction and the transfer of thermal energy by fluid circulation or movement of the hot particles in bulk to cooler areas in a material medium. Unlike the case of pure conduction, now currents in fluids are additionally involved in convection. This movement occurs into a fluid or within a fluid, and cannot happen in solids. In solids, molecules keep their relative position to such an extent that bulk movement or flow is prohibited, and therefore convection does not occur.
Convection occurs in two forms: natural and forced convection.
In natural convection, fluid surrounding a heat source receives heat, becomes less dense and rises. The surrounding, cooler fluid then moves to replace it. This cooler fluid is then heated and the process continues, forming a convection current. The driving force for natural convection is buoyancy, a result of differences in fluid density when gravity or any type of acceleration is present in the system.
Forced convection, by contrast, occurs when pumps, fans or other means are used to propel the fluid and create an artificially induced convection current. Forced heat convection is sometimes referred to as heat advection, or sometimes simply advection for short. But advection is a more general process, and in heat advection, the substance being "advected" in the fluid field is simply heat.
