There's a few ways, but the most common are:
1) Through proper accounting/inventory control - POS system keeps track of all
sales, recipes are inputted into the POS, count stock on hand, and input
invoices of received goods and you can spit out a clear picture of what you've
used, and what you're missing each week.
2) Liquor control pours that are connected to a monitoring system - these can
be either remote or a little ring you have to put the pour spout in for the
bottle to actually pour.
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Cheers! - Josh @ BarSim
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