Will Pouring Coffee Or Tea Into a Insulated Cup Release Toxins?

This year, in response to environmental protection, most people choose to use insulated cups to take out coffee or tea. However, we have heard that coffee and tea contain acidic components, which may corrode the thermos and release heavy metals. So, how to choose and use thermos cups to ensure safety?

Can a insulated cup hold coffee or tea?

Generally, insulated cups are made of stainless steel material with inner and outer walls, and a double-layer vacuum structure to truly exert their insulation function. The reason why stainless steel is called stainless steel is mainly because a certain amount of chromium must be added during the manufacturing process and fired together. When chromium comes into contact with air or oxygen in the environment, a special chromium oxide film will be formed to block the possibility of corrosion and heavy metal release.

So, compared to ordinary copper, stainless steel has relatively high corrosion resistance and oxidation resistance. It is precisely because stainless steel has the benefits of corrosion resistance and oxidation resistance that it is widely used in daily necessities such as pots, bowls, and pans, including the inner and outer walls of insulated cups.

During the brewing process of tea and coffee, as the storage time and brewing time are prolonged, tannic acid components will gradually be released, which will affect their flavor.

But the impact of tannic acid is only limited to this. In fact, tannic acid, which has an acid atom in its name and belongs to polyphenolic substances, is actually a type of nitrogen-containing alkaline substance with significant physiological effects in plant tissues, rather than an acidic component known to have corrosive effects.

Unless it is a high concentration strong acid, it will not cause damage to stainless steel. Therefore, it is safe to put concentrated fruit juice into a thermos. However, it should be noted that due to the high sweetness and high carbohydrate content of fruit juice, it is recommended to consume it fresh within 30 minutes of opening, or quickly store it in the refrigerator to prevent the proliferation of microorganisms and bacteria and spoilage.

As for milk, whether cold or hot, nutritious dairy products have always been a favorite food for bacteria and microorganisms. Once the storage environment temperature is between 20-30 ℃, it is easy to develop and lead to gastroenteritis. Therefore, both hot and cold milk should be consumed as soon as possible.

What should I pay attention to when choosing a thermos cup?

The thermos cups on the market are mostly made of 304 stainless steel (containing 18% chromium and 8% nickel) or 316 (18% chromium and 10% nickel, also known as 18/10 stainless steel). These 300 series thermos bottles have a relatively stable chemical structure, and generally hot beverages such as hot water, hot coffee, or hot tea do not corrode the thermos bottles. It is recommended that you check the SUS label on the bottle before purchasing, so that you can use it with peace of mind.

Although a thermos can keep warm for up to 6 hours, the temperature inside the bottle will also change with increasing storage time; Especially for beverages containing a large amount of sugar, if not consumed in a timely manner, they may breed a large number of bacteria and microorganisms, deteriorate, produce odors, and may cause gastrointestinal problems if consumed.

Therefore, it is recommended that tea and coffee should not be left for more than 2 hours, while dairy drinks that require low-temperature refrigeration should be consumed within 30 minutes and the thermos should be rinsed as soon as possible.

As for cleaning, if there are cracks or scratches inside the insulated cup, it is easy for bacteria to grow, and it will not reduce the rust and corrosion resistance of stainless steel. Therefore, it is recommended to avoid using hard steel brushes or diamond sponges when cleaning insulated cups. Instead, rinse with clean water or soak in natural cleaning agents to help remove dirt.

In addition to cleaning the bottle body, special attention should also be paid to the cleaning of the edges that come into contact with the mouth, the cup lid, and all rubber and plastic. The purpose of rubber, plastic, and silicone rings in stainless steel cups is to prevent leakage. There may be gaps between them and the stainless steel material, which is also the most prone to dirt accumulation, biofilm formation, and bacterial growth. Therefore, it is important to pay special attention to careful cleaning and use cotton swabs or pointed brushes to treat the gap dirt.

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