@AccountR 

"These purchases are expensed and reflected on the P&L report. Obviously these purchases make up the cost of the can of beer. This is where the problem comes into play."

I would suggest you get in touch with a good accountant/CPA or look at something like Ollie or Small Batch Standard.  Have you done that?  When you purchase supplies for producing beer, those costs are not expenses until the beer is sold.  Those costs should not be an expense when purchased, they should be capitalized into inventory then converted to finished goods when completed and then expensed to COGS when sold.