Cookbook:Deep Fat Frying
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Cookbook | Recipes | Cooking techniques | Frying
Deep frying involves fully immersing food in hot oil. It is an extremely fast cooking method, and, despite the use of liquid oil, is best classified as a dry cooking method.
With a deep fryer, deep frying is reasonably safe, but hot cooking oil is intrinsically dangerous, and one should be very careful so as to avoid fires and severe burns.
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[edit] Method
Deep frying does not actually make the food greasy if it is done properly. What happens is the water in the food repels the oil. However, the hot oil also boils the water within the food, and steams the food from the inside out. As long as the oil is hot enough and the food is not immersed in the oil for too long, no oil will enter the food itself. If the food stays in the oil too long, the water will steam out and the oil will penetrate the food. If the oil is too cool, the food won't be done before this happens.
Most fried recipes rely on either a coating of batter or breading, or on foods that have or produce a natural skin around the food such as potatoes or whole poultry with the skin on. The effect of this is that the outside of the food becomes crispy and browned while the inside is tender, moist, and steamed, similar to searing.
[edit] Safety
Deep frying can be extremely dangerous – hot oil can cause severe burns and is a leading cause of kitchen fires.
It should only be done using a deep fryer, and one should familiarize oneself with safe operation prior to use.
In particular:
- do not let water anywhere near the fryer, as this causes an extreme fire hazard – see chip pan fire;
- do not overfill – there must be space in the fryer for food to be added;
- do not overheat – oil is flammable and oil fires are extremely dangerous;
- do have a fire blanket immediately to hand; and
- do not have any children present.
Chip pans are extraordinarily dangerous, and should not be used under any circumstances – they are the leading cause of house fires in the UK, and further, may spill hot oil, causing severe burns. If you have a chip pan, please contact your local fire brigade, as they may offer to trade it in for a deep fryer, or can otherwise advise about the dangers.
[edit] Warning
Please contact the local fire brigade for advice before deep frying, as cooking oil fires are extremely dangerous and hard to fight, requiring special measures.
In case of any cooking oil fire, leave the house and contact the fire department immediately, and do not try to fight it yourself – your efforts are liable to end in disaster.
- Cook under a metal range hood: flames from burning hot oil can be 2 or 3 feet high, and can easily burn shelving.
- Regular fire extinguishers do not work on cooking oil; specialized extinguishers are required, which may not be available for residential use.
- If you place too much food into the oil, the oil can flow over the sides, causing fire or burns.
- Again, do not let water anywhere near hot oil, as this creates an extreme hazard.
- When the oil starts to give off continuous smoke, you have it far too hot – it is at the smoke point, and the oil becomes carcinogenic at this point.
- Turn off your deep fryer, and allow the oil to cool.
- It is likely not acutely dangerous – the fire point and kindling point are generally significantly higher than the smoke point, so the oil will not ignite without further heating – but it is extremely hot, and smoke is a warning sign.
- Next time, use a lower temperature setting or choose an oil with a higher smoke point.
[edit] Tips for frying
- starting with cold foods (good idea), generally frying temperatures are around 325–375 degrees Fahrenheit (160–190 degrees Celsius). It may be higher for small foods. If the oil is too hot, the outside will burn before the inside is done.
- When starting with warm or hot foods, the oil can be much hotter. (this is why the egg roll recipe instructs you to use hot filling, and why the fried fish recipe instructs you to microwave the fish before breading and deep-fat frying it)
- Filter your frying oil regularly, if your fryer has a filtering system.
- Cooled oil can be filtered with a tea strainer, kitchen paper, muslin or coarse coffee machine filter paper.
- Change the oil when it becomes extremely dark. If you don't, your food will all taste the same – fries will taste like fish, fish will taste like fries, and, in the end, everything will taste a bit rancid.
- A rule of thumb is to change oil each week under heavy use, or every three weeks if it's only used for frying vegetables.
- When using new oil in your fryer, add an extra 1.5 minutes to your frying time.
- Don't add too much food at one time; it will cool the oil too much.
- When breading with a dry powder, use an egg wash or viscous liquid (such as buttermilk) to make it stick to the food.
- When breading with a moist batter, use cornmeal, cornstarch or flour to make it stick to the food, and make sure batter is sufficiently dry on adding.
- Shake off excess batter or breading before frying; otherwise it will come off in the oil, requiring more frequent oil changes.
- Do not use a basket with food which could stick to the wires. Alternatively, suspend food in oil with tongs for ten seconds before releasing.
- Opinions differ regarding the storage of used frying oil. Some say frying improves with repeated use of the oil and use one batch of oil for three to six fryings, while others claim used oils are hazardous either due to bacterial growth or due to the breakdown of the oil into harmful compounds. Those who reuse oil disagree as to whether refrigeration is necessary, but generally agree that it is important to filter the oil and then store it tightly capped and away from light. Discard reused oil when it becomes dark or begins to smell "off".
- If reusing oil, add fresh oil for each use in order to extend its usefulness.
- Oil can be purified by deep-frying parsley. The parsley absorbs the odors in the oil. Watch for spatters!
