Deep frying is the process of transferring heat to food by immersing it in hot fat.
When deep-frying you aim to produce food that is juicy but not oily or greasy and is generally golden in color with a crisp outer layer. It is common to batter or bread foods which are to be deep fried in order to protect the food from the cooking fat and achieve the desired texture and color.
The following guidance applies when deep frying food:
- Ensure that your frying fat is not too hot or too cool . If your fat is too hot it will burn the outside of the food before it has cooked through and if the fat is too cool it is likely to result in a greasy end product. Most food is deep fried at temperatutes between 350°F (175°C) and 375°F (190°C).
- Use a cooking thermometer to measure temperature I think you will be surprised how inaccurate guessing when oil has reached the right temperature can be.
- Don't cook too much food at a time . It will lower the temperature of the cooking and may lead to a oily end product. ( see point 1 )
- Use high quality fat or oil with a high smoking point .. I really like using rendered beef fat but don't tell anyone ;-)
- Avoid getting uneccessary impurities into the oil such as water , bread crumbs , salt etc .
- Use clean well rinsed utensils and baskets.
- Keep your fat fresh .. Old fat doesnt fry well and makes food taste bad.
- If your fat or oil has been heated to the point smoking then you should replace it.
- Dont let food sit for too long after it has been deep fried . Serve it quickly.
Boiling is the process of transferring heat into food by immersing it in liquid which has reached it's boiling point and is bubbling rapidly. The most common liquids used for boiling are water based which have a boiling point of approximately 212°F or 100°C at sea level.
This technique is most commonly used when cooking starches and vegetables as the vigorous agitation will damage less robust foods and tends to make proteins tough.
Boiling water is a relatively simple procedure but it does pay to remember that the steam escaping from an uncovered pot contains a lot of energy so if you keep a pot covered and prevent the steam escaping you will have to put less energy in to from whatever heatsource you are using to make the water boil.
It is worth noting that water will boil at the same temperate regardless of how much energy you add to it so turning up the flame and putting the lid on the pot may bring it to the boil more quickly but it will not make it boil at a higher temperature. Atmospheric pressure on the other hand does influence the boiling point of a liquid with increased pressure ( e.g. using a pressure cooker ) increasing boiling point temperature and reduced pressure ( e.g. cooking at high altitude ) reducing it.
The following guidance applies when boiling food:
- Generally avoid boiling meats & fish it will make it tough if not careful.
- Avoid boiling delicate foods as it is likely to damage their structure.
- Leaving the lid on a pot whilst heating will help a fluid come to the boil quicker and will require less energy to maintain a boil.
- Adding more energy ( e.g. turning the flame up ) will not make a fluid boil at a higher temperature it is just a waste of energy.
- Use a pressure cooker if you want to increase boiling temperature and reduce cooking time.
- Increase cooking time when boiling food at high altitude to account for reduced boiling temperature (refer to point 4).