First, choosing a restaurant. Everyone knows the current situation in China—can you even find a place that doesn't use gutter oil?The answer is elusive, yet we must choose! For our health.
When selecting a restaurant, prioritize those with high foot traffic, strong operational capabilities, and robust profitability. Such establishments are precisely the least likely to use gutter oil. Struggling businesses with weak profitability, driven by cost-cutting pressures, leave restaurant owners with no alternative but to use low-cost oils—and gutter oil may end up on your table.
How to spot it once the food arrives?
This is actually the hardest part, as gutter oil is essentially colorless and odorless with complex components. But for our health, we have no choice but to train our eyes to spot it.
A: Look
If possible, visit the restaurant kitchen and check the oil's transparency.Pure vegetable oil appears transparent. Impurities introduced during production reduce its clarity. Check the color: pure oil is colorless. Pigments from the source material dissolving in the oil give it color. Examine sediment, which mainly consists of impurities.Place one or two drops on your palm, rub your hands together until warm, then carefully smell the aroma. Oils with off-odors indicate poor quality; foul-smelling oils are likely recycled cooking oil. Avoid any with mineral oil scent.Oils with a sour taste are substandard products. Oils with a burnt or bitter taste have already gone rancid. Oils with an unusual odor may be "gutter oil."
D: Listen
This one is a bit extreme—you'll have to endure the strange looks from the next table, okay?
Take one or two drops from the bottom layer of the oil, spread it on a flammable paper strip, light it, and listen to the sound.Normal combustion without sound indicates a qualified product; abnormal burning accompanied by a "sizzling" sound suggests excessive moisture content, making it unqualified; "popping" or explosive sounds during combustion indicate severely excessive water content and may indicate adulterated oil. For dishes served at the table, observe the color of the dish—this requires a keen eye.>There's generally no way to detect gutter oil used in cooking. It depends on the dish. For example, if a dish naturally has a light color, but it appears dull (meaning the color isn't vibrant—not exactly dirty, but hard to describe, you'll have to sense it), it might be gutter oil, though not necessarily. You definitely can't tell by smell...
Leftovers offer a highly reliable indicator.
After taking food home and refrigerating it, check after several hours. If the oil has solidified or partially solidified, it indicates poor-quality oil—likely reused or even drain oil.