Washing rice is common in Asian countries, although it is not a common procedure in our kitchens today. Gastronomic and hygiene reasons are behind this gesture.
Rice is one of the most widely consumed cereals. It is estimated that more than 500 tons of it are prepared in a thousand and one ways around the world every year. It is an essential cereal in our diet, full of nutrients, cheap, and versatile in different cuisines. This is why its preparation is very similar in different corners of the planet. One of its peculiarities is that, in certain countries, rice is washed before being consumed. A reason that can be explained by the subsequent cooking and also as a hygiene measure due to the fertilizers or substances it may contain.
Why do you have to wash rice?
Rice is washed to remove excess starch, a sugar, a polysaccharide that naturally gives rice a gelatinous and gummy texture, and to avoid impurities or substances harmful to our body.
Regarding starch, while it is true that in many recipes this gelatinous and gummy texture may be the final result that is expected, there are many recipe books where this result is not the desired one. For example, in Asian countries, rice is washed to completely remove the starch and thus achieve a loose, uncompacted rice with a perfect appearance for such well-known recipes as sushi.
Furthermore, at a global level, there is no strict control over rice production. That is why rice from developing countries needs to be thoroughly washed to ensure that it is free of impurities. In Europe, strict health controls ensure that the rice that reaches our homes is in the best organoleptic, safety, and hygiene conditions.
What is starch?
As we have said, starch is a polysaccharide formed by two molecules: amylopectin and amylose. These, in turn, are formed by small fragments, known as monosaccharides, of glucose. Although it has an important caloric contribution, vital for the correct development of the functions of living beings, it is often confused with gluten – which is a protein – since intolerances are associated with similar clinical pictures.
Starch is also a natural thickener commonly used in cooking. The growing trend of vegetarian and vegan diets makes it a perfect ally for better binding different textures, opening up a wide range of ingredients from cakes to different types of bread.
Benefits of washing rice
Among the benefits of washing rice, there are three of special interest both at a culinary and health level:
- This will prevent the rice from becoming compact. If we are looking for loose rice, which is necessary for many Asian recipes, it is essential to wash or rinse it until all possible starch is removed.
- Elimination of unwanted microparticles. Another reason is to reinforce the hygiene of the product being consumed. Just as we are used to washing fruit or vegetables, rice is a cereal that can contain unwanted particles or substances that can negatively affect our digestive system. Although safety and hygiene measures in Europe prevent cases of poisoning, nothing can be done with rice grains imported from third countries.
- Prevents rice from sticking to the bottom of the pot. Removing starch also means that if we run out of water during cooking, the rice will not stick to the bottom of the pot. By not using this type of sugar, a gelatinous mixture is avoided which, when in contact with heat, creates the characteristic brown crust that can be seen on the bottom of pots.
Contraindications of washing rice
Beyond the culinary point of view, there are no clearly defined contraindications that lead us to believe that pre-washing cereal may be harmful since the nutritional quality of the product and its properties are not lost.
What is lost is part of the Mediterranean culinary legacy. Beyond health reasons, Mediterranean cuisine is not based on loose-grain rice. Clear example are paella, since the type of grain used allows water and juices from meat and fish to be absorbed, achieving a totally different effect if this type of rice had been washed. Thus, gastronomic gems such as brothy rice, Italian risotto or Asturian rice pudding would be lost.
How to wash rice
The most basic washing involves passing the grains through water five or six times. There is no minimum number of washes since as the starch is released from the grains, the water takes on a characteristic whitish hue. We will know that we have eliminated a large part of the polysaccharides when the water comes out clear and without turbidity.
The hardness of the grain means that this procedure can be carried out in a Chinese strainer or similar with small pores. However, the Japanese tradition includes a more delicate rinsing, passing the grains of the cereal from hand to hand and removing, without roughness, all the starch.
Does rice contain arsenic?
Leaving aside culinary or gastronomic reasons, we must emphasize the micro-substances or heavy metals that rice may contain. Rice grains naturally contain arsenic, as well as other heavy metals such as mercury, cadmium, or lead. Studies show that, depending on the type of grain and its origin, the values (in micrograms, i.e., one part per million) range from 50 to 400 ppm (parts per million). This is very interesting since other cereal grains, such as wheat or oats, contain up to ten times less arsenic than rice.
There are several factors that make arsenic more prominent in the chemical composition of cereals. The pH of the soil, the chemical concentration of other compounds, or the availability of other nutrients cause rice plants to concentrate these significant parameters to a greater or lesser extent.
On the other hand, anthropogenic factors such as the use of fertilizers may be behind a concentration that, at first, may seem worrying. There is competition at the molecular level between arsenic and phosphorus, with similar reactivity characteristics, which causes phosphorus to be displaced by arsenic, precipitating or absorbing the latter by the plant itself and increasing its concentration in it.
The fact that rice is grown on flooded balconies means that the presence of arsenic, both organic (from compost) and inorganic, is greater. There are studies that advise a controlled use of water so that the absorption of the heavy metal by crops is minimised.
Arsenic is an extremely dangerous metal, associated with different types of cancer such as bladder, skin, or kidney cancer. Despite this, there is no reason for a health alarm. The World Health Organization (WHO) establishes tolerable parameters of arsenic that can be consumed by humans. Thus, most rice contains natural quantities below these figures, meaning that there is no health alarm regarding the consumption of rice and the presence of heavy metals. As Paracelsus said, “The poison is in the dose.”