To Meter Or Not To Meter: Optimizing Pre-Roll Production With Metering Trays

For companies that produce large amounts of pre-rolls, the secret weapon to creating consistent, high-quality pre-rolls quickly is the metering tray. It’s a handy little device that is not only the fastest and easiest way to prep just the right amount of flower to fill your cones, but to also keep you in compliance and speed up your process.

But exactly what is a metering tray, how does it work and why is it key to staying on the right side of state regulators? Let’s take a deeper look at these tools and how to use them.

WHAT IS A VOLUMETRIC METERING TRAY?

A volumetric metering tray is a tool designed to help you dose the same amount of flower into each pre-rolled cone in your cone filling machine. Since table-top pre-roll machines don’t have scales to weigh the amount of flower going into each cone, the metering tray helps ensure the same volume of flower falls into each cone.

And the key word here is "volume" - the metering tray is not actually weighing the flower, but since each hole is the same volume, in theory, the same amount of flower should be getting dropped into each cone.

For example, each slot in a half-gram, or 84mm cone, metering tray has a volume of about 3 cubic centimeters, which equates to about a half-gram of flower, give or take, with the exact weight always coming down to differences in the flower itself. For example, some strains are naturally denser than others, so a denser strain will weigh more in the same volume as a lighter, fluffier strain.

The way you grind your material may cause differences as well. When the flower is ground down very fine, it can pack tightly in the metering tray compared to a chunky grind, which will naturally have more air in the same amount of volume.

The same strain, ground to the same particle size can even weigh out differently if the moisture content changes over time. For example, if you have 50 pounds of flower ground for making pre-rolls and it takes you a week to produce all the pre-rolls, the flower could easily dry out over the week and with less moisture, the flower will weigh less.

So while the metering tray is a helpful tool to achieve consistent pre-rolls, it’s only as accurate as your input material, which boils down to a consistent grind, proper sift, and careful handling of the raw materials over time.

It’s important to accurately weigh your final products to ensure not only compliance with laws, but also to be sure you are not shorting your customers. Once you have your volumes dialed in, the metering trays provide a consistent fill.

HOW TO USE A METERING TRAY

Though simple to use, metering trays take a little practice to master.

To use them, you simply push your ground flower over the top of the tray and into each of the slots by hand, then place the tray on top of your cone-filling machine, pull out the metal sheet holding back the flower and turn on the motor.

There are differences between the metering trays for different machines though. The first – and most noticeable difference – is the shape. Each metering tray is designed to fit on a specific pre-roll filling machine, so the King Kone tray matches the hexagonal shape of the King Cone while the Fill N’ Fold’s metering tray is square.

While it doesn’t seem important, it does take a bit of practice to perfect filling techniques in either and our Pre-Roll Experts have found the square shape just a bit quicker to fill because it can be done in fewer motions.

However, in both of those cases, as well as any other volumetric metering tray, it’s important to give the tray a bounce or thump on a tabletop to make sure the flower in each slot is compacted.

METERING TRAY DIFFERENCES

Despite both machines using volumetric metering trays, there are some important differences to consider when choosing between the King Kone, the Fill N’ Fold and other machines, such as a Knockbox.

For example, because the King Kone can be used for multiple sized pre-rolled cones, as well as tubes, there are multiple tray sizes available. The King Kone offers three sizes of metering trays, 0.35 grams, a half-gram tray and .7 grams. To use metering for a 1-gram pre-roll, you’ll have to use the half-gram size twice. The King Kone also comes with a clearing tool to help remove sticky cannabis.

The Fill N Fold, on the other hand, comes with a work tray sized specifically for a single cone size, and the corresponding metering tray to go with it. Though the motor will work with any sized work tray, each size must be purchased separately, including the metering trays, which are available for all sizes, from the .3-gram mini dogwalkers all the up to the full-gram 109mm cones. The Fill N’ Fold also comes with a tamping tool to remove stuck material and 2 thin, plastic shims to add a little height to the metering tray, providing a little more filling volume on a single metering tray, making each tray slightly adjustable for different flower types.

The shims add just a little more volume to the openings, so sliding one or two between the tray and the machine gives you some wiggle room if one type of flower is extra fluffy and takes a little more space to get to your goal weight. It’s a simple way to make small adjustments for each strain you pack into your pre-rolled cones, so note which strains need some space to reach your goal weight.

While the shims are only available with the Fill N Fold, both machine manufacturers have additional metering trays in the works and Custom Cones USA can customize trays to meet your needs

METERING TRAY STICKING POINTS

One of the biggest sticking points when using a volumetric metering tray can be, well, the stickiness of your flower. Because the grinding process breaks open the trichomes and releases the oils inside, freshly ground flower is often stickier, which can cause additional resin build up and gunk up your machines, as well as restrict flow through your trays.

That’s why we recommend not using freshly ground flower in these trays.

As we’ve discussed, the inconsistent nature of cannabis flower can affect the volumetric measurements of a metering tray. Cannabis flower is highly inconsistent from harvest to harvest, let alone from strain to strain and because they are volumetric, the weights may not come out exactly due to the variable nature of the flower. Also, as a reminder, remember to factor in the weight of your cone in your final product.

Keep in mind that if your flower is particularly fluffy, you may, for example, need to use the .7 size volumetric tray to reach a half gram in weight. So be sure to play around a little with the thickness of the metering trays, and always weigh your final product as a quality control step.

That’s one of the reasons we always say that making quality pre-rolls starts with the grind and why it’s so important to sift your cannabis to ensure a consistent particle size for packing into your metering trays and filling machines. And because in this case, one size does NOT fit all, we actually recommend trying out different combinations of grinder and sifter screens to get the right particle sizes for your different strains of flower and then use those screens consistently to create repeatable results that ensure the volumetric trays work their best.

FINAL THOUGHTS ON METERING TRAYS

Whichever pre-roll filling machine you choose, once it’s dialed in, a volumetric metering tray can help speed your production process and ensure consistent, high-quality pre-rolls that keep your customers coming back again and again.

Contact the Pre-Roll Experts today to find out which machine, and which volumetric metering tray, is the right fit for your business.