How to Process Flower From Harvest to Fresh Frozen

Fresh frozen cannabis is changing the game for a lot of extraction companies, but if you want to capitalize on this massive and lucrative trend, you first need to understand the basics: What is fresh frozen? Why is it so popular? How is it resulting in better extractions? And perhaps most importantly, how do you process flower from harvest to fresh frozen? It’s easier than you may think, and it could give your extraction business a powerful competitive edge.

Fresh Frozen Cannabis for Live Rosin

Fresh frozen cannabis ready for processing. Image from Harmony Extracts via Ed Rosenthal.

What Is Fresh Frozen Cannabis?

The term “fresh frozen” refers to cannabis that has been de-fanned and frozen for later use. You would start by removing the fan leaves, cutting the stock, and then placing the buds inside of turkey bags or other moisture-resistant bags. Then you would place the bags in a freezer until you’re ready to process them.

Fresh frozen buds aren’t dried or cured in any way. The plant matter is frozen in its fresh, natural state, preserving all essential compounds therein. When it’s removed from the freezer, it should be processed immediately.

The Benefits of Fresh Frozen Cannabis

Fresh frozen is all about achieving a “live” product. It’s the foundation of live resin and live rosin, and it’s one of the best ways to create a premium-grade extraction that discerning consumers are willing to pay a premium for. There are three main benefits to fresh frozen:

It preserves the living essence of the plant

Cannabis produces volatile terpenes, and because they’re so volatile, a lot of those terpenes are lost during the drying and curing process. By some estimates, as much as 95% of a plant’s terpenes can be sacrificed during the curing process. The fresh frozen process preserves the living essence of the plant by keeping those terpenes intact.

Fresh Frozen Cannabis Trichomes Macro

Macro level terpene- and cannabinoid-rich trichomes on Do-Si-Dos fresh frozen cannabis. Image by Erik Christiansen @erik.nugshots.

When you freeze your buds, you give yourself the best shot at preserving the natural flavors, aromas, and experiences—you’re extracting a live plant, and most consumers prefer the taste of a live product.

It’s less vulnerable to environmental conditions

Another benefit, from a business perspective, is that freezing makes it easier to achieve a quality product.

The drying and curing process requires specific environmental conditions. Depending on where you’re harvesting your cannabis, the elements might not be on your side. If you’re trying to dry and cure cannabis in the Pacific Northwest or somewhere really humid, you have to worry about moisture. In a place like Colorado, you have to make sure you’re not over-drying.

So there’s a lot involved in getting a good dry and cure. But with fresh frozen, you don’t need to worry about it. Just de-fan it, bag it, and put it in the freezer. You do need freezer space, but it’s ultimately much less of a headache, and it affords you the ability to make a higher-quality product.

It allows you to stop the clock

One of the most practical benefits of fresh frozen is that you can freeze your harvest and then process it down the road. If you have surplus cannabis, you can save a portion of your harvest for later. If you’re not ready to start extracting now, your material doesn’t have to go to waste. You decide when to process your cannabis.

There’s some disagreement as to how long you can freeze your buds before the cannabinoids and terpenes start to degrade. Research indicates that the compounds can remain intact for years, but ideally you should only freeze for as long as you absolutely need to.

Processing Flower From Harvest to Fresh Frozen

The processing of fresh frozen cannabis is generally easier than drying and curing and can be summed up in the following steps:
  • Step 1: Harvesting the plants. Start by cutting the plants down when they’ve reached the maturity level that you’re looking for. You’ll also need to remove the fan leaves (some cultivators do this before harvesting, but it’s ultimately a matter of personal preference).
  • Step 2: Hanging the plants. The harvested cannabis is typically hung to protect the delicate trichome heads. The trichomes are the lifeblood of your extraction, so you need to preserve them with extreme care.
  • Step 3: Further reducing the plants. Before the plant matter can be collected for freezing, it needs to be further processed down until you’re left with just the buds.
  • Step 4: Freezing your buds. Once you have your buds, the next step is to place them into sealed, moisture-resistant bags and put them in the freezer to be frozen. Some cultivators will bring dry ice to the garden so that they can start freezing the buds as soon as they’re cut. Just note that, while dry ice can be stored in a cooler near cannabis during transport, it should be separated from the plant material—never touching it.

When placing your cannabis in the freezer, make sure not to smash it all together. You want a loose to medium pack so that when you retrieve the cannabis for processing, you don’t have a giant popsicle brick to contend with. You want to be able to break it up and ensure the best surface area for your extraction.

Another important thing to keep in mind is that you don’t want the cannabis to thaw before you extract it. Fresh frozen is very transportable; you can easily move it from your freezer to your extraction facility. Just try to keep it frozen during transport.

How to Choose a Freezer for Fresh Frozen Cannabis

You don’t need any kind of specialty freezer for fresh frozen. In fact, you don’t even need a super deep freeze. Any freezer that reaches 0°F should work just fine as long as it has ample space for all of your frozen buds.

As long as you keep the cannabis firmly inside, it should hold up for years. There are even studies that attest to this. One Italian study specifically looked at the degradation of cannabinoids (particularly THC) over a period of 4 years under the following controlled storage conditions:
  • Light and room temperature
  • Darkness and room temperature
  • Refrigeration
  • Freezing

At room temperature, THC degrades almost completely after 4 years. With refrigeration, THC experiences moderate degradation. With freezing, the THC is almost entirely intact after 4 years.

According to the study: “The contents of THC and CBN in cannabis products (hashish and marijuana) were found to significantly depend on the storage time, unless samples are stored at -20°C (-4°F), indicating that freezing is the best storage condition to avoid the reduction of the cannabinoids content over time.”

Things You Can Do With Fresh Frozen Cannabis

Fresh frozen cannabis is used primarily for cannabis extraction. Specifically, there are two extraction methods that support fresh frozen: hydrocarbon extraction (to create live resin) and solventless extraction (to create live rosin). Each method has its pros and cons.

Hydrocarbon Extraction

Hydrocarbon extraction is a method that relies on hydrocarbon solvents (e.g. propane, butane). The plant material is extracted within a closed-loop system and then purged to remove most traces of solvents. Post-processing may include dewaxing or winterization, depending on the goals of the user.

Fresh frozen cannabis was originally popularized thanks to hydrocarbon extraction. William Fenger, better known as “Kind Bill,” perfected the method in a closed-loop system in 2013. Prior to that, some extraction techs had tried processing fresh frozen in an open blast system, but the results were less than stellar.

Live Resin Cannabis Concentrate

Live resin made at Kush Masters.

Fresh frozen cannabis can be placed directly into a closed loop system and extracted as-is. It doesn’t matter the quality, the strain, or the condition of the material. Other solvent-based extractions, like distillate, ethanol, and supercritical CO2, won’t support fresh frozen, and so hydrocarbon remains the standard for live resin.

Solventless Extraction

Solventless extraction, and specifically the ice water hash (or “bubble hash”) method, is the best way to create extracts from fresh frozen. Not only does it give you a better flavor profile, but it results in a higher-quality product—especially when the resulting concentrate is further extracted into rosin using a rosin press. Ice water hash is the crème de la crème of fresh frozen extraction because no method does a better job of preserving the original essence and character of the plant itself.

Live Rosin Solventless Cannabis Concentrate

Chem Dawg live rosin badder made at Kush Masters.

One reason why the ice water hash method is so effective at maintaining a live product is because the plant matter remains frozen through every step of the extraction process. The cannabis is removed from the freezer and immediately submerged (and agitated) in freezing cold water. The trichomes are separated, filtered, and isolated inside of a bubble hash machine, and the collected hashish is then used on its own or further refined into rosin.

Serious connoisseurs understand the unique properties that only an ice water hash extraction can provide, and they’re willing to spend more for that special flavor and unique experience. If you want to build your brand on quality and purity, this is the way to go.

If you do plan to use the solventless extraction method with fresh frozen, it’s very important that you opt for the ice water hash extraction before the rosin extraction. You cannot place fresh frozen cannabis on a rosin press and expect a good result. Fresh frozen biomass contains about 75% moisture (and the same is true of uncured biomass). If you try to press it, you’re just going to end up with a soupy mess of rosin and water because the cell walls tend to burst more easily. You only want to press dry biomass, and the ice water extraction method can get you there (just don’t forget to freeze-dry your hash before taking it to the rosin press).

Why Solventless Is the Better Extraction Method for Fresh Frozen

Some of the benefits of solventless extraction may be obvious: It requires no volatile solvents, it requires less complex and costly equipment, and there’s less room for human error. But some of the benefits may be less obvious.

Most notably, solventless affords you an inherently higher-quality product, which you can promote at a higher price point as you encourage greater consumer confidence. It’s a shelf-tested product that customers can put their faith in.

There’s an important reason why solventless is better. You cannot remediate fresh frozen material using the ice water hash process. In other words, solventless extraction can’t save a poor-quality batch. It would just be wasted. That’s why solventless extraction companies have to be especially diligent about choosing the right trichome-rich strains and ensuring that the batch is free of mold and other contaminants. You must have a premium product to begin with.

Trichomes in hash washing water

Trichomes settling at the bottom of the Bruteless ice water hash washing vessel.

Hydrocarbon extraction systems, on the other hand, will remediate lower-quality cannabis. Because it’s a process of dissolution, you’re going to extract the vast majority of the cannabinoids no matter what—because the solvent is dissolving them. This might sound like a benefit on the surface; after all, you can use whatever you have on hand, whether it’s fresh frozen, trim, or a rejected batch of moldy biomass. It’s all going to get made into sausage.

Ultimately, though, this is one of the biggest problems of hydrocarbon extraction. What goes in is not always the same as what comes out. So if the cannabis is poor-quality in the first place, hydrocarbon extraction can actually remediate your starting material into an extract that is still sellable. This isn’t possible with solventless extraction as the material you put in is going to be exactly what you get out. There is no hiding bad starting material with solventless. For this reason, discriminating connoisseurs are understandably skeptical of hydrocarbon. If you want to make a premium product and sell it at a premium price, go solventless.

Live Rosin Gram Vape Cartridge and Gummies

Äkta Creations cold cured live rosin badder (L), live rosin cartridge (C), and live rosin gummies (R) all produced from fresh frozen starting material. 

And here’s another major benefit of going solventless: The ice water hash method also gives you far more options for the end SKUs you can create. Because you preserve so many more cannabinoids and terpenes in an ice water hash extraction (assuming you’re doing it well), you can make everything from solventless cartridges to shatter to crumble—and everything in between.

Experience the Wonders of Fresh Frozen for Yourself

If you’re thinking of experimenting with fresh frozen cannabis, our first piece of advice is to just do it. It will be a game changer for the quality and value of your extractions.

Our second piece of advice is to skip the closed-loop systems and go solventless. It will ultimately mean the difference between a great product and an outstanding product. And in today’s competitive cannabis market, you can’t settle for second best.