Here’s how Colorado implements its marijuana tax based on weight. Many, many growers have to pay that tax, so it needs to be simple — and to be verifiable.
I have been told the scales cost a couple of hundred dollars, so they are a step up from cheap food scales like these: http://thesweethome.com/reviews/best-kitchen-scale/
“For weighing very small amounts very precisely—such as espresso, spices, or leaveners—you’ll want to invest in a digital pocket scale. These weigh in increments of .1 or .01 grams. Like their name implies, they’re small enough to fit in a pocket. (. . . [C]ulinary students often call these drug dealer scales, but they’re also used by jewelry makers.) Thankfully, they’re cheap.
“For espresso, we like the $18 American Weigh SC-2KG pocket scale ($18), which measures in .1 gram increments. It’s very easy to use, with a 4-by-4-inch platform (big enough for a large mug), a tare button, and a bright blue backlit screen that stays on as long as the scale does.”
Before a license is issued, inspectors check the grower’s scale.
Growers can’t send product out without a “manifest,” a piece of paper that lists who is driving, what kind of car, and what packages are on board the transporting vehicle. There’s a form for that. All product is sealed in tamper proof containers with zip-ties. No container can hold more than a pound.
The Department of Revenue threatens spot inspections of scales, too. And the Department reacts if it gets a lead about questionable business.
You’d need an expensive scale to get such accuracy as in this example, showing 0.8942 ounces in one package. http://media.wix.com/ugd/73c73e_d980e5423d7d4e20a3dcb9fa290e56d5.pdf. That example is a real case, I think. But the tax for bud is only 66 cents a gram, so you don’t need ultra-accurate results. The rate for trim is 12 cents a gram.
Yes, Colorado’s Constitution calls for a 15-percent producer tax, but they couldn’t make that work with vertically integrated producers, so they collect tax by weight – even for arm’s-length sales! More here.
A California friend points out: The California Department of Agriculture has a bureau of weights and measures that oversees such matters.
The Center for New Revenue 