Steaming

Steaming is a specialized cooking method that uses steam to prepare food.

In this process, the food is fully immersed in steam with no air present. As the steam reaches the food, it undergoes condensation, which means it turns back into liquid droplets. These droplets drip away from the food rather than soaking it. This technique is highly valued for being healthy and energy-efficient. It requires much less water than boiling because it utilizes the excellent thermodynamic heat transfer properties of steam.

The mechanism of steaming relies on the continuous boiling of water to create vapor. This vaporized steam excludes the air around the food, carrying heat directly to it. Unlike double boiling, where food is not directly exposed to steam, steaming allows direct contact. This contact results in a moist texture. Pressure cooking is a different method that uses a sealed vessel to achieve pressure steaming. Most people use a food steamer, which is a circular container made of metal, wood, or bamboo.

Different types of steaming vessels offer unique benefits to the cook. Modern metal steamers are often made of aluminum or stainless steel. Traditional bamboo steamers are also very common, especially in East Asian cuisine. These bamboo versions often feature a central chimney to distribute steam among different tiers. The bamboo lid is particularly useful because it absorbs excess moisture. This prevents too much water from condensing back onto delicate food. Other modern options include microwaveable silicone steamers and plastic-hybrid steamers.

Steaming has a very long history across many different parts of the world. Some of the earliest examples were found in China's Yellow River Valley. Stoneware steam cookers there date back as far as 5,000 BCE. In Japan, steaming was used during the Stone Age. During the Bronze Age, examples of steaming appeared in Italy and Sardinia. In Cochise County, Arizona, people used steam pits about 10,000 years ago. By the eighth century CE, thin strips of cypress were used to construct steamers.

This cooking method provides significant nutritional advantages over other techniques. A 2007 USDA comparison showed that steaming preserves more nutrients than boiling. For example, steaming reduces folic acid by only 15%, while boiling reduces it by 35%. Steaming also reduces vitamin C by 15%, compared to a 25% reduction from boiling. In broccoli, steaming resulted in 42% higher amounts of glucosinolates than boiling. Furthermore, steaming is better at retaining phenolic compounds and β-carotene in vegetables like carrots.

Many cultures use steaming to create iconic and diverse dishes. In China, steaming is essential for dim sum, such as har gao shrimp dumplings and siu mai.

It is also used for pearl meatballs and mantou buns. In Japan, glutinous rice is steamed to make mochi rice cakes. Japanese cuisine also includes chawanmushi, which is a savory egg custard. In Mexico and Central America, tamales are made by steaming masa dough inside corn husks or banana leaves.

Steaming connects to broader culinary traditions and modern convenience. In many Chinese households, steaming meat dishes is common, even though they take longer than stir-frying. In Thailand, steaming is seen as a form of minimalist cooking. Even in Western cooking, steaming is a primary method for preparing vegetables. While many frozen foods were once reheated by steaming, many people now use microwaves for faster results. However, the specialized steam ovens and microwaveable steamers ensure the technique remains a staple in modern kitchens.