Reviving deep-frying oil with umeboshi pickled plum

When the same oil is used repeatedly for deep-frying, it gets darker and  thicker (higher viscosity) and starts to smell, especially when used to deep-fry seafood or meat. Adding some new oil to used oil every time you deep-fry is one way to slow down the deterioration process. Another effective method is to deep-fry umeboshi pickled plums.

The citric acid contained in umeboshi is said to bond with aldehyde, a chemical substance that oxidizes oil and thus is the cause of deterioration. Simply deep-fry one or two  umeboshi or umeboshi seeds before, in-between or after food preparation to revive oil.

Some people say only the flesh of umeboshi should be used, as seeds can burst in hot oil. I use umeboshi seeds saved when using the flesh for various dishes, and I have not had any seeds burst in oil in my kitchen. But since I cannot guarantee there won’t be an explosion, as a precaution use  a splatter guard or put seeds after finishing deep-frying and oil temperature goes down to 270 F/130 C.

Other notes on oil for deep-fried dishes:

• Tempura dishes taste better when cooked in new or newer oil.
• Some dishes, such as karaage fried chicken and tonkatsu pork cutlets, take on that yummy golden color more easily when cooked in previously used oil.
• In terms of ingredients,  deep-frying vegetables, seafood, and meat is the preferred order to extend oil life. Depending on what you cook, oil can be used 4-5 times in about a month while adding new oil and treating with umeboshi as above, filtering between use, and storing properly.
• Ingredients seasoned with spices and herbs or batter leave the flavor and smell of seasonings in oil, and deep-frying these items in new oil often means it can’t be reused for different dishes.
• Oil that is very thick or highly viscose is clearly old and should not be used for cooking.