Good news, this is now live in Breww 
The new COGS by stock item and utility/other cost report breaks your cost of goods sold for any period down into the stock items behind it: the ingredients, the packaging (bottles, cans, boxes, labels and so on) and any utility/other costs you record on your batches, with each item’s cost apportioned to what you actually sold. You can group it by stock item type, sub-type or individual stock item, and the “Product and…” options show the same breakdown for each product you sold.
Full details are in the announcement: New pre-built report: COGS by stock item and utility/other cost .
Thanks to everyone who voted, and we hope this helps!