That doesn't matter though. They are still a commercial brewery and as such, subject to duty. They are selling you a product, the fact that you supplied most of the ingredients and some of the effort doesn't matter to revenue.
It's better answered in their flyer from the first post.
[quote:xjoib5qj] The final calculation for excise
fees will be based on the amount of beer produced and the alcohol content less the small brewer
rebate[/quote:xjoib5qj]
Don't forget, you are also responsible for packaging costs. I'm not sure if they will be providing that service or if you are expected to show up with containers to take your beer away.