How do I change an alcohol tax in BC (5% + 10%) similar to the gst/pst tax, instead of 15% altogether?

Hi there, 

Welcome to the QuickBooks Community. Recording your transactions the right way is a good method for keeping your books clean. Rest assured, I'll be happy to show you how to set up a custom tax rate in QuickBooks.

Based on what you've described, I encourage you to check out the following article that shows you how to: Add a custom sales tax rate for an existing sales tax agency. The article provides the necessary steps required for you to add the tax rates you've described to your account. 

Feel free to ask other questions. I'll be on standby in case you need anything else.