Help with Product Attributes and Order Export

New Member
1 0 0


I am looking for guidance on how to add a custom attribute or metafield to an existing product in my Shopify store. The goal of this is somewhat complicated, so please excuse the long question.

We sell alcohol on our website, and each month we need to submit reports to the states we ship our products to, which includes the total gallons of alcohol shipped.

The goal of this attribute or metafield would be to associate a number to each product that would represent the total gallons in that product. For example, one 4-pack is 0.5 gallons.

Then, I would want to create a system so that at the end of checkout, this attribute is summed to show the total gallons in the order and have this number exported with a CSV file. For example, a customer orders two 4-packs which are 0.5 gallons each. Therefore, the total gallonage in the order is 1 gallon which is automatically summed in the order.

Once the order is placed and exported, is there a way to show a separate line item in the CSV file that displays the total gallons ordered as "1" in the same order line without having to manually sum the gallonage in each order?

We also have Shopify Plus, so being able to use this metafield or product attribute in Shopify Flow would be desired. Is there a way to do this as well?

If there is a better way to do this with an app or separate customization, I am open to suggestions. I can also provide clarity to any questions that arise.

Thank you for your time and advice!