When it comes to washing fruit, a quick search on Baidu will reveal a myriad of methods. So, which method is relatively more reliable and reassuring? We selected six common methods and conducted a simple experiment.
Since strawberries are now largely out of season, we chose fragrant pears and blackcurrants for this washing experiment. Everyone knows that fragrant pears have a layer of wax on their surface. They feel greasy to the touch, and after handling them, a waxy residue is left on the hands, requiring soap to clean. Blackcurrants, on the other hand, are primarily covered in a white bloom, with a small amount of wax, and do not feel smooth to the touch.
Method 1: Soaking in plain water
Time: 1 hour
Amount: 1 bowl
Place the fragrant pears and blackcurrants directly into a bowl of plain tap water. Soak for an hour, then change the water and rinse once more.
Result: The water quality showed little change, with only a small amount of debris visible. The wax on the surface of the pears was slightly reduced, feeling less greasy than before. The blackcurrants showed little change, with some bloom still remaining.
Method 2: Washing with starch
Time: Half an hour
Amount: 2 spoonfuls
Add two spoonfuls of starch to a bowl of water, stir to mix, then add the fragrant pears and blackcurrants. Soak for about half an hour, then change the water and rinse once more.
Result: The water quality didn't change much (as the starch made it turbid to begin with), with a small amount of debris floating on the surface. The wax on the surface of the pears was mostly washed away, revealing the pear's natural lumen, and it felt very clean to the touch. The white substance on the blackcurrants' surface remained.
Method 3: Rubbing with salt
Time: Approximately 5 minutes
Amount: 4-5 spoonfuls
Sprinkle salt directly on the surface of the fragrant pears, rub them repeatedly with your hands, then rinse with clean water.
Result: This method works by using the grains of salt to repeatedly scrub the fruit's surface to remove wax. The effect was quite good; the wax layer on the pears was mostly gone, and they no longer felt greasy. However, washing just one pear required about four or five spoonfuls of salt, which felt a bit "too wasteful".
Method 4: Using shell powder
Time: Half an hour
Amount: 2-3 grams
The shell powder was a brand bought online. The instructions said it could not only wash fruits and vegetables but also be used for washing clothes and dishes. Add about 2-3 grams of shell powder to a bowl of water, stir, then add the fragrant pears and blackcurrants. Soak for about 30 minutes, and finally rinse with clean water.
Result: After soaking for about 2 minutes, an oily layer could be seen floating on the water's surface. Around the 20-minute mark, the surface was completely covered with a thin layer of wax, much like candle drippings in water. A touch with the hand caused the white wax to stick to the fingers. After rinsing with clean water, the wax on the surface of the pears was mostly gone, revealing a natural lumen and not feeling greasy. The white substance on the blackcurrants was also mostly gone, and their skin felt very "crisp" when rubbed.
Method 5: Soaking in rice water
Time: Half an hour
Amount: 2 bowls
Take two bowls of rice water that has been used to soak rice for about 10 minutes, add the fragrant pears and blackcurrants directly, soak for about 30 minutes, then remove and rinse with clean water.
Result: The rice water, for which we had high hopes, proved to be basically useless against wax. While debris did float to the surface, the wax on the pears and blackcurrants was still there, feeling as if they hadn't been washed at all.
Method 6: Dish soap
Time: 20 minutes
Amount: 3 drops
The test used a certain brand of green tea dish soap, claimed to be natural and pollution-free, and safe for washing fruits and vegetables. Following the instructions, we added 3 drops of dish soap to clean water, added the fragrant pears and blackcurrants, and soaked for about 20 minutes before rinsing twice with clean water.
Result: The water quality showed little change, and no debris floated to the surface. After rinsing with clean water, it felt as if the wax and white bloom were mostly cleaned off, and neither felt greasy to the touch.
【Concluding Remarks】
Starch is the most practical choice
After the experiment, new questions arose. Based on the results of this test, it's clear that for removing wax from fruit surfaces, using starch or shell powder yielded the cleanest and most satisfactory results. The principle behind both is actually similar: they don't dissolve the wax (which is highly stable and not easily removed by ordinary substances) but rather use an adsorption effect. This is very suitable for washing fruits with thin skins.
Since the cleaning effect is the same, the key then comes down to cost-effectiveness. A 90g can of shell powder costs around 70 yuan online, and 2-3 grams is needed per use. In contrast, starch is much more affordable and can be bought right in your neighborhood.
Long-term soaking in plain water also works
In this experiment, what was originally thought to be the least reliable method—soaking in plain water—turned out to be a bit of a surprise. This shows that if you don't trust any additives, simply soaking in plain water can be effective. The prerequisite, however, is that it must be a long soak. For instance, in this test, the soaking time exceeded an hour. Of course, soaking some fruits for a long time might affect their texture.
The reliability of salt needs further investigation
Rubbing salt on the fruit's surface is, in principle, the same as using starch or shell powder—small particles scrub away surface debris through friction. However, there is another theory: salt, or sodium chloride, can actually stabilize certain pesticide components, potentially backfiring. Regarding this claim, the evaluation center consulted Professor Chen Ligeng from the College of Agriculture and Biotechnology at Zhejiang University. He stated that there is no specific research on this matter, and if you are truly concerned, he suggests peeling the fruit before eating.
【Expert Advice】
Bloom and wax are both within the edible range
Simply rinse fruit with clean water
Professor Chen Ligeng said that for some fruits, like blueberries, plums, and grapes, a white bloom may appear on the skin. There is no need to be overly concerned. The bloom is a secretion of the fruit and is related to its freshness, "the presence of bloom indicates the fruit is very fresh." For blueberries, for example, they can be eaten right after picking. Grapes may use some pesticides during their young fruit stage to prevent disease, but after bagging, they are generally not sprayed. Therefore, any residue on the skin would have mostly lost its efficacy. For this type of fruit, Professor Chen's recommendation is to rinse directly with clean water.
As for the wax on fruits like fragrant pears and apples, it should normally be edible wax, derived from secretions of plants and animals. It is edible and harmless to humans. When washing these types of fruits with shell powder or rice water, floating matter can be seen on the water's surface. A relevant person from the Hangzhou Agriculture Bureau stated that this floating matter, besides bloom, could also be dust accumulated from exposure to the air, or condensates of early-stage pesticides on the fruit. The latter would have also lost its efficacy by the time the fruit ripens.
For fruits that cannot be peeled, like strawberries and bayberries, Professor Chen believes the best way to wash them is to rinse with clean water, then soak in cold, boiled water for about half an hour.