How much water to add to the rice cooker?

In this brief guide, we will answer the question “how much water to add to the rice cooker?”, discuss what is the correct amount of water to obtain the best results for each type of rice.

Rice (Oryza sativa L.) is one of the most important agricultural food crops for more than half of the world’s population. Globally, about 150 million hectares is estimated to be under rice cultivation with an annual production of 500 million metric tons (1).

How much water to add to the rice cooker?

The amount of water to be added to the rice cooker is generally 1 ½ cups of water per 1 cup of dry rice (6). 

To be exact, studies indicate an optimal water-to-rice ratio of 1.9:1 for a soft-cooked rice grain using instrumental texture analysis (3).

However, the water to rice ratio varies, depending on the type of rice and the quality of the rice cooker. You should follow the instructions provided by the rice cooker manufacturer for optimal results.

What determines how much water to add to the rice cooker?

Factors related both to the properties of the rice grains and the operation of the rice cooker may influence the amount of water to be added to the rice cooker.

The characteristics of the rice grain, such as variety, dryness, age (storage time), the amylose content of rice is considered as the main parameter of cooking and eating quality. 

The higher amount of amylose in the grain, the greater the water absorption. As a consequence, rice varieties with higher amylose will need more water to cook. 

According to studies, if paddy rice is stored for a period of 3-4 months following harvest, at temperatures of about 15°C, it results in greater expansion in volume and water absorption during the cooking process (7).

Also according to studies, proteins in the rice grain affect the amount of water the rice absorbs early in cooking, which determines the final texture of cooked rice. Therefore, rice containing higher amounts of proteins, such as brown rice, would have greater water needs.

Regarding the characteristics of the cooking machine, there are a variety of rice cookers, with different operations and sizes. Although rice cookers have the same operation principles, they may have particularities.

The energy input of the machine and the model of the cooker determine the rate of temperature rising, the water loss through evaporation and therefore the need of water for the cooking. In addition, some models can switch the cooking function to the warming function automatically after the end of the cooking operation (8).  

Cooking time and water amount are important factors that determine the tenderness of cooked rice as well as stickiness to a great extent. High volume expansion of cooking is still considered to be the good quality for many consumers (2). 

Therefore, it is crucial to add the correct amount of water to the rice cooker in order to obtain the best results.

What are the water needs of different rice varieties?

The water needs of different rice varieties are given below (6):

The properties of different rice varieties and their effects on the cooking water needs are described below: 

Brown rice

Brown rice needs more water to cook. For long-grain brown rice, you will require about 2 ¼ cups of water per cup of rice. The cooking time of brown rice is a bit longer than that of white rice. They take 40-50 minutes to cook. The longer cooking time needed to prepare brown rice may be a barrier for consumers to opt for this variety of rice.

Brown rice is preferred by most health-conscious people because of its particular characteristics of whole grain, high fiber, and less processed. Because only the outermost layer (the hull) of the rice kernel is removed during processing, brown rice retains most of its nutritional value (eg, dietary fiber, essential fatty acids, and various vitamins and trace elements) (4). 

White rice

White rice generally requires less water than brown rice for cooking and is prepared in less time as compared to the time taken by the brown rice to be cooked. The requirement of water varies with the variable length of the gran but ideally, we can use 1 ½ to 2 cups of water per cup of rice. Short grain rice requires less water as compared to long-grain rice. 

Elongation of rice grains during cooking is dependent basically on rice variety and degree of milling. The rice varieties which absorb high quantities of water during cooking are soft varieties and these varieties which absorb low amounts of water during cooking are considered as hard rice varieties (5). 

Depending on the characteristics, such as size, shape and length, the cooking time varied from 14.5 minutes to 25 minutes among the tested fine rice varieties (2).

Jasmine rice/ Basmati rice

Indian style rice recipes using Jasmine rice or Basmati rice require drier rice, and hence the amount of water required per cup of rice is lesser. To cook jasmine rice or basmati rice according to Indian style recipes you may need 1 ½  cups of water per cup of dry rice.

A study showed that a water-to-rice ratio of 1.5:1 is optimal in producing a cooked aromatic white Jasmine rice flavor profile not dominated by any single attribute or group of attributes. 

This study identified the water-to-rice ratios 1.125:1 and 1.875:1 are optimal for producing fluffy and sticky cooked rice, respectively. Rice manufacturers should therefore, recommend and advertise the water-to-rice ratios 1.125:1, 1.5:1, and 1.875:1 wanting a fluffy, balanced flavor, or sticky cooked rice, respectively (3).

Other FAQs about Rice which you may be interested in.

How to fix undercooked rice in rice cooker?

How to make puffed rice in the microwave?

How to tell if brown rice is bad?

Conclusion:

In this brief guide, we answered the question “How much water to add to the rice cooker?”, discussed what is the correct amount of water to obtain the best results for each type of rice.

References:

1. Atera, Evans A., Florence N. Onyancha, and Eucabeth BO Majiwa. Production and marketing of rice in Kenya: Challenges and opportunities. J Develop Agric Econ, 2018, 10, 64-70.
2. Dipti, S. S., et al. Physicochemical and cooking properties of some fine rice varieties. Pakistan J Nutr, 2002, 1, 188-190.  
3. Maleki, Clinton, et al. Preference mapping of different water‐to‐rice ratios in cooked aromatic white jasmine rice. J Food Sci, 2020, 85, 1576-1585.
4. Zhang, Geng, et al. Substituting brown rice for white rice to lower diabetes risk: a focus-group study in Chinese adults. J Am Dietetic Assoc, 2020, 110, 1216-1221.  
5. Hettiarachchi, H. A. P. W., et al. Diversity of physical and cooking quality characters of selected traditional and improved rice varieties in Sri Lanka. Sri Lankan J Biol, 2016, 1.
6. All about cooking rice. University of Wyoming Extension. 2023.  
7. Wiset, Lamul. Effects of high temperature drying on rice quality. Diss. UNSW Sydney, 2004.
8. Ahamed, Raju, et al. Modeling and performance analysis of electric rice cooker. Proceedings of the Conference: 3rd International Conference on Mathematical Applications in Engineering. 2014.