We often hear the advice to "drink more hot water," but it seems no one has ever specified exactly what temperature the water should be. Matters concerning water, such as warm water, honey water, tea, and formula milk, must be handled with the right balance!
35°C Warm Water for a More Comfortable Intestine
Drinking a glass of warm water in the morning can help your gastrointestinal system "lighten its load." Moreover, warm water can help relieve constipation, reduce the incidence of cerebral thrombosis and myocardial infarction, and aid in absorbing the nutrients from your breakfast. Therefore, be sure to drink 1-2 glasses (200-400 ml) of warm water after getting up in the morning.
Dr. Lu Shijun from the Food and Nutrition Development Institute of the Ministry of Agriculture states that to care for the stomach and intestines, it is not advisable to drink water that is too hot or too cold. Overly hot liquids can damage the esophageal mucosa and stimulate mucosal hyperplasia, inducing esophageal cancer—a conclusion already established in the medical community. Consuming cold drinks, on the other hand, can cause the gastrointestinal mucosa to suddenly contract due to the cold, leading to capillary constriction, smooth muscle spasms, and potentially causing gastrointestinal discomfort, cramps, or even diarrhea.
Warm water can promote blood circulation and prevent cardiovascular diseases. For the average person, it is best to drink warm water at 35°C~40°C, and salt should not be added (salt water can exacerbate hypertonic dehydration, making you feel even thirstier. Furthermore, morning is the first peak of elevated blood pressure for the human body, and drinking salt water will push the blood pressure even higher).
45°C Water for Best Formula Milk Dissolution
From a sensory perspective, using water at around 45°C to prepare infant formula results in the most authentic aroma, best solubility, and a uniform milk liquid without any residue on the container walls.
Experiments have shown that if the water is too cold (e.g., 25°C), the formula will have undissolved white granules (commonly known as not dissolving properly). If the water is too hot (70°C), the milk will show a small amount of large white granules, with formula residue on the container walls and some lumps. Formula milk prepared with (90°C) water produced a large number of large white granules and lumps.
This shows that formula milk cannot be completely dissolved at low temperatures, while at high temperatures, the proteins in the milk denature, forming granules and lumps that are difficult to dissolve. The experiment proves that 45°C water offers the best solubility for formula milk.
55°C Water for Preserving Honey's Nutrients
According to Dr. Lu Shijun, honey contains various enzymes, and the activity of these enzymes is an important indicator of honey's biological activity and a measure of its quality.
The national standard stipulates that the amylase value of qualified honey products should not be less than 8 mL (1% starch solution)/(g·h). Experiments have shown that if the water temperature for dissolving honey exceeds 60°C, the enzymes will denature and lose their activity quickly. Therefore, it is recommended to use warm water below 55°C to prepare honey. This way, the honey can melt well while preserving its nutritional components to the greatest extent.
85°C Water for a Mellow Taste and Better Nutrition in Tea
Tea polyphenols are one of the important bioactive components in green tea. The optimal temperature for their dissolution is around 80°C. The caffeine in green tea is the main source of the astringent taste in the brew, and its optimal dissolution temperature is around 88°C. Therefore, choosing 85°C for brewing can, on one hand, maximize the dissolution of tea polyphenols while reducing the dissolution of caffeine, ensuring the tea liquor is a tender, bright green with a fresh, mellow, and sweet taste. Brewing tea with 85°C water ensures the rapid unfurling of the tea leaves and the release of its aroma.