Packaging Material Use Efficiency of Commercial PET and Glass Bottles for Mineral Water

Round 1

Reviewer 1 Report

Presentation of the results should be improved:

Bottle weights (Fig. 5). There are not statistics given for the bottle / closure and label weights - even if this is one of the interesting facts for the industry.

I suggest adding a table with the statistical data for bottles, closures and labels. Please consider as an example for bottles:

For labels there should be a differentiation in plastic and paper labels/sleeves and for closures in aluminium and plastics.

line 322: it is recommended to split section 3.3. Shelf life and costs in

3.3. shelf life and 

3.4. costs

line 365: Cost comparison of reusable vs. single use is missing - would be interesting to add

Conclusions:

It is recommended to rework the conclusions part because there is no real conclusion for the reader presented but only a few somewhat unconnected observations.

- What are the main results of this paper?

- What are the limitation of the study 

- What recommendation could be given to industry?

- What additional studies are recommended?

lines 387-389: sentences incomplete 

line 396: cost efficiency was not investigated (would be the total cost of ownership consisting mainly of packaging costs and logistic costs). This was not part of the study, there was only a comparison of retail prices! - please correct

line 403-404: meaning unclear, overpressure is not the right term

lines 408-412 are unclear - carbon dioxide amission has no impact on material use efficiency.

no 

Author Response

Dear Reviewer 1,

thank you for comments.

“Presentation of the results should be improved:

Bottle weights (Fig. 5). There are not statistics given for the bottle / closure and label weights -

even if this is one of the interesting facts for the industry.

I suggest adding a table with the statistical data for bottles, closures and labels. Please consider

as an example for bottles:“

The reviewer is right that statistical data would be desirable here. However, the authors decided against this because there is no uniform, statistical population. The packaging differs to some extent in terms of shape, wall thickness and possibly also in the finer details of the choice of material. Therefore, the authors do not consider it advisable to treat the samples as a uniform population for which statistical evaluations should be used. These aspects should be examined in more detail in a follow-up study and the samples should be categorized more closely. Important in our study, and not previously shown, is the large variation in packaging weights. Nonetheless, extreme values (minimum and maximum values) can be easily read from the graphs.

“For labels there should be a differentiation in plastic and paper labels/sleeves and for closures in

aluminium and plastics.“

To our impression the label weights are sufficiently presented. The aluminium closure weight is presented in Fig. 5c, and in the text: “At glass-bottles only aluminium caps were found with a weight between one to three gram.”

“line 322: it is recommended to split section 3.3. Shelf life and costs in

3.3. shelf life and

3.4. costs“

Section was split as proposed.

“line 365: Cost comparison of reusable vs. single use is missing - would be interesting to add”

The analysed glass bottles were only reusable bottles, not single use. Reusable and disposable PET bottles are compared in Fig. 11b, and 11c.

“Conclusions:

It is recommended to rework the conclusions part because there is no real conclusion for the

reader presented but only a few somewhat unconnected observations.

- What are the main results of this paper?

- What are the limitation of the study

- What recommendation could be given to industry?

- What additional studies are recommended?

lines 387-389: sentences incomplete

line 396: cost efficiency was not investigated (would be the total cost of ownership consisting

mainly of packaging costs and logistic costs). This was not part of the study, there was only a

comparison of retail prices! - please correct

line 403-404: meaning unclear, overpressure is not the right term

lines 408-412 are unclear - carbon dioxide amission has no impact on material use efficiency.”

The conclusions were amended, following the recommendation of reviewer 1.

Sincerely Yours

Anna Greß, Kajetan Müller, Sven Sängerlaub

Reviewer 2 Report

The authors have used simple analyses procedures for packaging efficiency of the commercial pet and glass bottles used for packaging of water. The depth of the study conducted by the authors on data collection and analyses are very minimal for research publication consideration. There is a serious lack of statistical analysis of the collected commercial data. Overall the work presented in the manuscript is not up to the standards of publication.

The quality of english only requires minor editing.

Author Response

Dear Reviewer 2,

thank you for comments.

“The authors have used simple analyses procedures for packaging efficiency of the commercial pet and glass bottles used for packaging of water. The depth of the study conducted by the authors on data collection and analyses are very minimal for research publication consideration.“

The reviewer is right that the study uses readily available and easily controllable measurement methods. However, the authors believe that the large sample size generates scientific added value. The scattering of bottle weights shown has not yet been described in this way for mineral water in the literature. These values are particularly relevant for life cycle assessments. They allow the calculation of different scenarios based on the minimum and maximum material use for bottles, which are presented in our study. Furthermore, our results are important as a benchmark for the optimization of bottle weights.

“There is a serious lack of statistical analysis of the collected commercial data. Overall the work presented in the manuscript is not up to the standards of publication.”

The reviewer is right that statistical data would be desirable here. However, the authors decided against this because there is no uniform, statistical population. The packaging differs to some extent in terms of shape, wall thickness and possibly also in the finer details of the choice of material. Therefore, the authors do not consider it advisable to treat the samples as a uniform population for which statistical evaluations should be used. These aspects should be examined in more detail in a follow-up study and the samples should be categorized more closely. Important in our study, and not previously shown, is the large variation in packaging weights. Nonetheless, extreme values (minimum and maximum values) can be easily read from the graphs.

Sincerely Yours

Anna Greß, Kajetan Müller, Sven Sängerlaub

Reviewer 3 Report

1- Could you please provide more detailed explanations regarding the methods used to assess the lifespan of reusable PET and glass bottles, as well as the criteria used to determine the number of possible reuses?

2- Have you considered including considerations about the overall environmental impact of different packaging types, particularly considering CO₂ emissions throughout the lifecycle, water consumption, and energy requirements for production and recycling?

3- What are your recommendations for the bottled beverage industry to improve the efficiency of packaging material use, while considering environmental, economic, and sustainability considerations?

4- I suggest including additional data on recycling and reuse practices in different countries or regions. This could provide a more comprehensive perspective on sustainability trends in the bottled beverage industry and help readers better understand regional variations in waste management and packaging material usage.

Author Response

Dear Reviewer 3,

thank you for comments.

1- Could you please provide more detailed explanations regarding the methods used to assess the lifespan of reusable PET and glass bottles, as well as the criteria used to determine the number of possible reuses?

Information about shelf life was read from the labels, pls. see chapter 2.3. In chapter 3.1.1., and 3.3 estimations for shelf life restriction by water and CO₂-loss are provided. The number of possible reuses were taken from published data. In our study this was not measured. The scientific literature misses information and studies about number of possible reuses because bottle damage is relevant and it might be influenced by different handling procedures.

2- Have you considered including considerations about the overall environmental impact of different packaging types, particularly considering CO2 emissions throughout the lifecycle, water consumption, and energy requirements for production and recycling?

These investigations are very important and we have referred to corresponding studies in our paper. However, one weakness of these studies is that they assume or use bottle weights that do not reflect the entire spread on the market. This is where our study is valuable, because minimum and maximum weights are presented. A low weight leads to a lower environmental impact of the packaging. The reduced shelf life should not have too critical an effect here.

3- What are your recommendations for the bottled beverage industry to improve the efficiency of packaging material use, while considering environmental, economic, and sustainability considerations?

Recommendations are provided in the chapter conclusions.

4- I suggest including additional data on recycling and reuse practices in different countries or regions. This could provide a more comprehensive perspective on sustainability trends in the bottled beverage industry and help readers better understand regional variations in waste management and packaging material usage.

This data and information would be very interesting. In Europe and also globally, however, there are differences in utilization and also in the maturity of the technology. There are also different transportation routes. Such a presentation would therefore be very complex and relevant for a separate review. The value of our results lies in the comprehensive presentation of bottle weights and their dependence on the filling quantity. This data is a good basis for subsequent assessments of sustainability. Relevant studies for mineral water were referred to in the introduction. Such studies can draw on our data in the future.

Sincerely Yours

Anna Greß, Kajetan Müller, Sven Sängerlaub

Reviewer 4 Report

The manuscript presents the study on the influence of the material used in mineral water bottles on parameters such as filling rate, carbonization and cost and shelf life. The text presents the results obtained in a concise and structured way in several other works in the area. Therefore, I recommend accepting this work with minor revision, mainly in aspects related to the organization of the images.

1 – In Figure 1 on page 2, which parameter does the x-axis of the graph refer to?

2 – On line 68 of page 2, the expression Figure is capitalized, conveying the expectation that some figure will be presented in the text to describe the theme;

3 – On line 211 on page 6, please check which figure the text refers to, as the figures are numbered incorrectly;

4 – Figure 5 presented on page 7 should be Figure 4;

5 – In lines 235 and 236, please review which figures the text refers to, as the figures are numbered incorrectly;

6 - On line 251 of page 7, please review which figure the text refers to;

7 - On line 282 of page 9, please review which figure the text refers to;

8 - In line 303 on page 10, please review which figure the text refers to;

Author Response

Dear Reviewer 4,

thank you for comments.

“The manuscript presents the study on the influence of the material used in mineral water bottles on parameters such as filling rate, carbonization and cost and shelf life. The text presents the results obtained in a concise and structured way in several other works in the area. Therefore, I recommend accepting this work with minor revision, mainly in aspects related to the organization of the images.”

Thank you.

1 – In Figure 1 on page 2, which parameter does the x-axis of the graph refer to?

We added an explaining sentence in the caption.

2 – On line 68 of page 2, the expression Figure is capitalized, conveying the expectation that some figure will be presented in the text to describe the theme;

Amended.

3 – On line 211 on page 6, please check which figure the text refers to, as the figures are numbered incorrectly;

Amended.

4 – Figure 5 presented on page 7 should be Figure 4;

Amended.

5 – In lines 235 and 236, please review which figures the text refers to, as the figures are numbered incorrectly;

Amended.

6 - On line 251 of page 7, please review which figure the text refers to;

Amended.

7 - On line 282 of page 9, please review which figure the text refers to;

Amended.

8 - In line 303 on page 10, please review which figure the text refers to;

Amended.

Sincerely Yours

Anna Greß, Kajetan Müller, Sven Sängerlaub

Round 2

Reviewer 1 Report

Revision of the article is o.k., no further comments