A Very Precautionary Tale

Recently, a customer went in to buy soup from a catering outlet and was served it in a single wall cup. The soup had been microwaved.

The lid and cup were from two different manufacturers. The cup was so hot to hold that the customer opted to hold the cup by the lid, and as they got into their car the cup fell away from the lid, spilling the contents over their crutch resulting in 1st degree burns, and requiring skin grafts.

Single wall v double wall

There is nothing wrong with a single wall cup for hot drinks, and in some ways a single wall cup will allow the user to ascertain the temperature of the drink, avoiding scalding their mouth. As an example – and not related to this instance – Starbucks have sleeves available for customers, but their serving temperatures are so low that they are not really needed.

Double wall cups although offering better insulation, are more of a marketing concept, to give the drink that premium feel / look, and in some ways could lead to scalding as the consumer does not know how hot the drink is.

Serving temperatures

Cup manufacturers have no control over what temperatures people use our cups at, mechanically they can be used at 100 ⁰C. Coffee shop owners and those that use takeaway cups must complete their own risk assessment and having ascertained a safe temperature to serve drinks – which may involve adding some cold water – they should do regular testing to make sure they maintain the safe temperature.

Cup manufacturers generally would not recommend what a safe working temperature is, as it changes with every use /venue. It is up to the venue to decide, maintain and record the standards.


Extreme care needs to be taken when using microwaves, and although paper cups will withstand quite high temperatures, there is a massive danger of getting scalded / burnt. Therefore, the instructions may say microwave for 3 minutes, but if inadvertently microwaved for 6 minutes it could raise the temperature to over 150 ⁰C if there is fat in the cup.

Water boils at 100 ⁰C, and cannot go higher in normal circumstances, but if there is any fat in the cup temperatures could go to the temperature for boiling fat (think of a chip pan). It is very important that hospitality outlets carry out their own risk assessment when serving any hot food especially liquids.

Operationally they can go as high as a maximum of 100 ⁰C but not as a serving temperature.


It is recommended that hospitality outlets use lids and cups from the same manufacturer. Unfortunately, there are low-cost lids circulating from various wholesalers, but in the event of an accident it will make it very difficult to ascertain what component was at fault. Lids are susceptible of going saft with heat and popping off, so testing when cold is not sufficient.


If you are purchaser of takeaway cups ensure that you buy them from a reputable supplier. Always work towards using cups and lids from the same manufacturer and train the staff to ensure the lids are correctly affixed to the cup.

Carry out HACCP on your takeaway cups as part of your overall Health & Safety policy and ensure that if you microwave the liquid in or before it goes in the cup it is below 100 ⁰C.

Photo by Olena Sergienko on Unsplash

Posted: 21st April 2023