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A metrological look at refillable packaging

With the advance of packaging-free supermarkets, consumers are more often weighing products themselves. What steps should manufacturers take to assure consumers that they are paying the right price for the goods they put on the scale?

Packaging-free products

Now that supermarkets are looking for ways to become more sustainable and reduce the amount of plastic packaging, so-called refill stations are becoming popular. These stations give consumers the opportunity to fill their own containers with dry goods such as pasta, muesli and nuts. The Dutch supermarket chain Albert Heijn has also started AH Packaging-free stores, which use dispensers for more than 70 different products.

Of course, self-service scales for loose goods are nothing new, but until now they have mainly been used for fruit and vegetables. As packaging-free products expand, weighing them is also becoming more important. Scale certification enables manufacturers to meet the demand for accurate and reliable scales. The Netherlands Measurement Institute (NMi) can help with this.

High-Quality Controls

It is NMi’s fundamental role as the designated authority to ensure that the weight indicated by a machine – and the price consumers pay for a product – is accurate and fair. The first step for this is to perform a conformity check on devices to determine if the units are performing to the manufacturer’s specification. This includes running a software test to find out if the device is showing accurate, correct weight information. NMi can also certify manufacturers to perform their own initial verifications, under a quality system, saving the manufacturers time and money in the process.

An important part of the conformity checks is determining whether a measuring instrument falls within the correct, maximum permissible margin of error category. This is a method of knowing and guaranteeing that the instrument is working accurately. To do this, you need to know the verification scale interval – also known as the e – value – where the smallest interval can be used to calculate the price based on weight in commercial transactions. Suppose the e – value is 2 grams, then the scale is tested in steps of 2 grams. From 0 grams to 1 kilo, the maximum allowed margin of error is around 1 gram, from 1 kilo to 4 kilos it is 2 grams and from 4 to 6 kilos around 3 grams.


The rise of more packaging-free products and the introduction of dispensers is an extension of current supermarket practices; after all, most consumers are already familiar with self-service scales. The existing legislation therefore applies to the new scales used at the refill stations.

Nevertheless, there is a potential weight-related loophole that supermarkets should avoid. For example, if consumers bring their own containers, all weighing scales require a ‘tare’ button to account for the extra weight. There must therefore be an element of trust that the consumer does not first fill his own packaging before he or she resets the machine in order to get (a part of) the products for free.

For countries such as the Netherlands, there are no obligations that require scales to be re-verified on a regular basis. However, supermarkets are responsible for the maintenance of the scales and they must ensure that the scales remain accurate year after year. For example, shops not only ensure that they are ready for random inspections, which the government is authorized to do. After all, maintenance by the manufacturer also contributes to customer confidence and the associated reliability of the prices that are paid.

It’s an exciting time for supermarkets and manufacturers as shopping continues to evolve into a more efficient, eco-friendly experience. But to maximize the benefits of packaging-free options, dispensers and scales must meet the requirements to ensure consumer trust and acceptance. Bodies such as NMi play a vital role in supporting manufacturers with accurate weighing equipment and the best service to consumers.

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