Whether for grabbing coffee before work, or buying hand-shaken beverages for afternoon tea, many consumers have started the habit of bringing their own containers, putting sustainable lifestyle habits into practice. In selecting a travel mug, some would put more emphasis on suitable capacity, while others would be more concerned with thermal insulation performance and leak-proof efficacy. The Consumer Council tested 18 models of tumblers and travel mugs, and found that the nominal capacity (defined as the water level 10mm below the lid’s inserted closure) of 5 models was more than 10% less than the stated capacity, thus falling short of the relevant labelling requirement of European standard. In 1 model, even when water was filled all the way up to the lid, the maximum capacity was still less than the stated capacity by more than 10%.
As for the thermal insulation efficacy, the performance of the various models exhibited great differences, for hot water not less than 95°C being put in the models for 6 hours, the water temperature varied between 26.3°C and 63.8°C. In 2 models, the thermal insulation efficacy was particularly outstanding; 8 models performed satisfactorily in the testing with cold water. For cold water at 5°C (+/-1°C) being put in the models for 6 hours, the water temperature could be maintained at below 11°C; in 3 plastic models that held cold water, after 6 hours the water temperature was already close to the temperature of the testing environment (20+/-2°C). Overall, for models made of plastic, with a smaller capacity and/or less tightly sealed lids, the thermal insulation efficacy was inferior. In addition, the leak-proof performance in more than 60% (12 models) was ideal, whereas in the remaining 6 models, the body of 1 model was wide at the top and narrow at the bottom and with a relatively heavy handle, causing it to overbalance on an inclined surface, posing a higher risk in causing burn injuries to users with hot drinks pouring out of the mug. The Council reminds manufacturers to improve the product design and the ability of the lid to be sealed tightly, so as to increase the safety assurances and the confidence of users, in fulfilling an environmentally friendly lifestyle. Furthermore, although all models passed the relevant tests for material safety, given that the compartment of certain travel mugs were rather narrow and difficult to clean, while some models had many components, consumers are reminded to take special care in cleaning after use, so as to prevent bacteria from breeding.
The Council purchased 18 models of tumblers and travel mugs from retailers, including 7 models equipped with a drinking straw, and 11 models of a typical tumbler or coffee mug style, and all with a lid. The models were priced from about $80 to $425, with purported capacities ranging from 350ml to 900ml. The physical tests on this occasion made reference to the European standard BS EN 12546-1 for insulated containers for domestic use and in accordance with laboratory designs, to assess the capacity, thermal insulation efficacy, anti-leakage ability and stability tests. In addition, it was arranged for each model to be tried out by 3 triallists to assess the ease of use. The 4 models that received a rating of 4.5 points were all priced above $240.
Nominal Capacity Differed by as Much as Over 20%
Stated Capacity of 5 Models Not Compliant with European Standard
Many consumers have travel mugs of various capacities at home, for easy usage on the go, yet if the actual capacity is different from the stated capacity, there is a chance that in purchasing a beverage, the travel mug would be unable to hold the whole drink, causing wastage or overflowing. The tests were conducted in accordance with European standard, in filling the models with room temperature water until the water level was 10mm below the lid after it was closed, and this was taken as the nominal capacity. Out of the 18 tested models, 14 recorded a nominal capacity that was 3.33% to 20.24% below the stated capacity. In 5 models, the discrepancy even exceeded 10%, thus failing to comply with the European standard that allowed for a 10% discrepancy. The biggest discrepancy was noted in 1 model that was priced the lowest (about $80). Its stated capacity was 420ml, but its measured nominal capacity was just 335ml, a discrepancy of over 20%. At the same time, even if the water level was filled right up to the lid or with the lid partially immersed in water to measure the maximum capacity of each model, in 1 model with a purported capacity of 600ml, its maximum capacity was only 532ml, which was 11.33% below the stated capacity. The Council reminds manufacturers that their product design must take into consideration the actual usage by consumers and clearly and accurately state on the product label the actual capacity. In addition to reflecting the test results to the manufacturers, the Council has also passed the results to the Customs and Excise Department for following up.
Thermal Insulation Efficacy of Models Made of Plastic Was Inferior
It is believed that thermal insulation efficacy is another major consideration in selecting a travel mug. If food is stored at an unsuitable temperature for a prolonged period, there is a chance that germs may breed and thrive. If food or beverage with a large amount of germs were ingested, it might lead to discomfort such as stomach pains, diarrhoea or vomiting. With reference to the European standard in testing, each model was filled with hot water of no less than 95°C to the level of the nominal capacity, then after closing the mug with the original lid, the models were placed in a testing environment (20+/-2°C) for 6 hours, and the water temperature was then measured. The results showed that the thermal insulation efficacy of the models differed greatly, with water temperature dropping to 26.3°C to 63.8°C: The performance of 2 models made of stainless steel were outstanding, with water temperature maintained at over 60°C. Another 6 models were able to maintain the water temperature at over 50°C, their performance being ideal; 7 models had water temperatures ranging from 41.7°C to 47.7°C; the remaining 3 models, made of plastic, had water temperatures that ranged from 26.3°C to 29.0°C only, the thermal insulation efficacy being significantly inferior.
As for cold insulation, the tests filled the models with cold water at about 5+/-1°C and they were placed in a testing environment (20+/-2°C) for 6 hours, and the water temperature was then measured. The results showed that in 8 models, after 6 hours the water temperature was still maintained at below 11°C, performance being outstanding; for 3 plastic models, the water temperature had risen to 20.5°C to 22.0°C, being very close to the temperature of the testing environment, indicating weaker cold insulation efficacy.
All in all, the insulation efficacy of travel mugs made of plastic was inferior. However, the stainless steel models did not all perform with excellence, reflecting that the product’s material was not the only factor affecting the thermal insulation efficacy. Other factors such as a lower capacity, a less airtight lid, the structure of the product (whether there are features such as double insulation or vacuum design), the thickness of the stainless steel, etc., could all possibly affect the insulation efficacy. However, the current test did not factor in the product’s structural design or material thickness, hence the thermal insulation efficacy of the said characteristics could not be assessed.
Satisfactory Leak-proof Performance for Most Models
Design of 1 Model Made it Susceptible to Overbalancing
When using travel mugs to hold drinks, leakage or spillage would entail cleaning up afterwards. In testing the models in an experimental environment, water was filled up to the nominal capacity level, the lid was then closed, and the model was turned upside down for 1 hour. The results showed that more than 60% (12 models) exhibited no leakage, indicating satisfactory leak-proof performance. The other 6 models that had water leakage were subjected to a second stage of tests, where they were put on a 45° inclined surface for 1 hour to see if water would leak out from the sides. The results showed that all 6 models did not exhibit leakage, reflecting that the silicone seals performed satisfactorily. It is worth noting that 3 of the models had explicitly stated that “the product is not airtight”, “the product is not leak-proof” or “splash-proof”. Meanwhile 7 models claimed to be leak-proof, and these 7 models did not exhibit leakage during tests, aligning with their claims. Consumers who are particularly concerned with the leak-proof performance of travel mugs should carefully read the product description when selecting a product.
If a travel mug is placed on an inclined surface and overbalances, it could create a hassle. The test was conducted in accordance with the European standard, with the models placed on a 10° inclined surface. The results showed that 1 model tipped over whether it was empty or filled with water, likely due to its design, which featured a taller structure, a narrow bottom, a wider top, and a relatively heavy handle. The Council opined that even though the thermal insulation performance of that model was relatively good, the leak-proof performance was only mediocre, and if it was used to contain a hot drink, there is a risk of overbalancing and causing burn injuries to the user. The Council reminds the relevant manufacturer to improve the safety and leak-proof performance of the product design, to avoid consumers having to dispose of the product due to inconvenience.
Some Models Claimed to Be Suitable for Hand-shaken Drinks Yet Straws Got Clogged by Toppings
Consumers who are fond of hand-shaken drinks might prefer travel mugs that come with a drinking straw. In 6 out of the 7 models with a drinking straw, the official websites or promotional videos claimed that they were suitable for Taiwanese-style drinks or hand-shaken beverages. However, triallists found that only 3 models allowed smooth drinking of beverages with toppings such as tapioca pearls, nata de coco, or herbal jelly, while the other 4 models had frequent clogging of the drinking straw by such toppings. The straw’s inner diameter, length and restricted movements due to the lid design, all appeared to affect the smooth drinking experience. The Council recommends that consumers who wish to purchase travel mugs for hand-shaken drinks should visit the physical stores to examine the product’s design, the size of the drinking straw and the swivel range, etc. For those used to shopping online, they should ascertain the specifications and refund arrangements, so as to prevent wastage in case they could not get refunds for unsuitable purchases or wrongly purchased products.
Material Safety Was Satisfactory
Regular Dismantling and Cleaning to Prevent Germ Growth
All models passed the durability test of opening and closing the lid 1,000 times, showing satisfactory performance for the anti-corrosive and stain-resistant parameters. Stainless steel, ceramic coatings, plastics and silicone gaskets had all passed the relevant safety tests, assuring consumers of their safety. However, triallists commented that 3 models had narrow bodies, making it difficult to clean the interior. In 6 models, drink residue often accumulated near the sip hole. The Council reminds consumers that some of the travel mugs had many components that required time to disassemble for cleaning one by one, especially sealing gaskets should be removed and cleaned regularly, otherwise stains may remain, leading to the breeding of germs and bad odour. Consumers should note that some silicone gaskets and plastic lids have similar colours, making them easy to be overlooked during cleaning.
Consumers may refer to the following tips when selecting and using travel mugs:
- Those who prioritise insulation efficacy are recommended to select stainless steel travel mugs with airtight lid and verify the insulation duration. On the other hand, consumers who do not require insulation, and tend to drink large amounts of water, may consider plastic models for a lighter weight;
- Avoid overfilling. It is recommended to fill up to 2cm below the rim of the mug, so as to avoid spillage when closing the lid which may result in burn injuries, and also to prevent the plastics or silicone materials in the lid from being immersed in the drink for long periods which could accelerate ageing of the lid, affecting the sealing and durability;
- Do not fill with carbonated beverages such as soft drinks, to prevent the drink from spurting out due to internal pressure;
- Avoid storing drinks inside the mug for extended periods, especially for dairy-based drinks, to minimise food safety risks;
- Pathogenic bacteria generally breed and grow rapidly between 4°C to 60°C. For food safety, hot foods/drinks should be stored at temperatures above 60°C, whilst cold foods/drinks should be stored at temperatures below 4°C to inhibit bacterial growth. Consuming foods and drinks with high levels of bacteria may cause stomach pains, diarrhoea or vomiting;
- If mildew is found in the silicone gaskets, or the components are found hardened, they should be replaced promptly. In selecting a travel mug, choose a brand and model with replaceable components to extend the product’s lifespan.
Download the article (Chinese only): https://ccchoice.org/579-tumblers-and-travel-mugs
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