Curing Cannabis

Lately, when cannabis growers hear about curing and cannabis, it’s some piece of clickbait about medical marijuana, but curing isn’t just something the plant can do to us, it’s something we can do to the plant.

After the plants have been tenderly administered to for weeks, and the buds have grown fat, been harvested, and trimmed, the owner of those buds faces a choice.

On the one hand, they can make the buds open for consumption immediately, by selling them to their distributor, or if they’re growing for their own use, by whatever method they prefer. On the other hand, they can take some extra time to make their buds tastier, stronger, and smoother by curing them.

For many commercial growers, curing cannabis doesn’t seem like it’s a process that’s worth their time. It can be a finicky process, it’s time-consuming, and compared to the immediate profit a cannabis grower can see by selling their newly harvested crop, the delayed gratification may be a bridge too far.

However, as state cannabis markets settle into place, growers will face increasing competition from one another, and a small grower may find that cornering the market as a provider of high quality aged cannabis is a profitable niche.

Regardless of how you grow, or the intended consumer, it’s worth knowing a bit about what curing does to cannabis, and how to do it. With that in mind, we’re going to do a quick overview of the subject here, and give you a basis from which you can learn more if you’re interested.

When the bud is freshly harvested from the plant and dried out, that’s a different thing entirely from the bud being cured. Although the practice of giving the buds some time to desiccate before trimming is referred to ‘dry trimming’, that’s just meant in comparison to trimming the buds as soon as they’re cut from the stem.

Even dry trimmed buds are far from water-free, and there’s still some moisture locked tight in those leaves.
Getting that moisture out is not a quick process, but here’s how it’s done.

The process starts with drying out the buds just like they would normally, by hanging them in a cool, dark place. At the start of drying out, the buds are at more than 70 percent relative humidity, with soft, flexible buds and stems.

The drying process takes anywhere between two and seven days, during which you’ll want to take regular humidity readings with your hygrometer, looking for somewhere between 65 and 70 percent humidity. Size is a factor, and thicker stems will dry out more slowly, so it’s important to keep a close watch.

The plant is ready for the next phase when the bud starts to take on a crispy texture, and the stems are still flexible, but not soft. At this point, the buds should be moved into jars being sure to leave enough room in the jar to get put a hygrometer in. You can either leave the stems attached to use them as an indicator of flexibility or remove them to save space.

The important part here is to make sure the jar’s atmosphere stays below 70 percent humidity. A good safety measure is to check the hygrometer in each jar after it’s been closed for an hour and let any that break 71 percent cure in the open a little longer. This is the pre-cure phase, and the goal is to get the moisture in the jar down to 65 percent humidity.

In the pre-cure phase, we start managing how much we’ll risk when it comes to mold and mildew. Getting to 65 percent leaves us the maximum amount of time to cure with, but if the crop has had a lot of troubles with mold, that may be too much cure time, and just ruin our harvest. If you’re worried about mold issues, you can go down to 65 percent relative humidity in the jar to be safe.

While in this phase, you’re depriving the moisture of a chance to evaporate and forcing the moisture inside of the bud to reach an equilibrium with the air trapped in the jar. The buds will feel a bit wetter, but so long as your hygrometer isn’t spiking when you close the jar (climbing one percent per hour is too fast), the process is working as intended.

During the pre-cure, you lower the moisture of your buds by ‘burping’ the jars, or leaving them open for one or two hours, once every 24 hours, or every 12 hours if you’re concerned about the moisture level. Each burp releases the air that’s reached equilibrium and lets fresh air in allowing a newer, lower equilibrium to be reached.

Somewhere between 65 percent and 62 percent relative humidity, you can start curing your buds. It’s as simple as slowing down the rate at which you burp your jars. You might try one hour a week instead of one hour a day. There is definitely room for experimentation.

If you have the patience, try curing a single crop on three different schedules, and see what results in the smoothest flavor.

In this part of the process, moisture transfer is a lot slower, so it’ll take longer for the moisture to come out of stems and the buds’ centers. That means it’ll also take longer for your hygrometer readings to be an accurate representation of the moisture in both the jar and the buds. Near the end, it might be a day and a half before the reading is truly accurate.

Your buds will be ready to enter long-term storage when they reach 60 percent humidity or less. Once you reach 55 percent, more curing won’t do anything to the flavor. You can stop curing at any point in this range. Storage is as simple as putting the buds in a completely airtight container.

You may well wonder at this point why curing the buds slowly produces better results than a quicker drying process. Well, the long answer is a lot of complex biochemistry, but the short version is that it gives bacteria time to break down carbohydrates. Chlorophyll breaks down into a bunch of chemicals, including magnesium, which gives smoked cannabis a harsher flavor. Magnesium and the other complex carbohydrates are in turn broken down, and each round removes burs from the taste while leaving the terpene profile and THC/CBD ratios intact.

Like many things in the cannabis market, what constitutes the ideal cure varies from grower to grower and strain to strain, also, it’s as much an art as a science. Some consumers may feel like a slightly harsher taste denotes a bud with more of an impact, and prefer a fresher bud as a result.

There are risks to curing, as a dark, moist environment is an invitation to mold and mildew. However, the proof is in the pudding, as they say, and if you put a little thought into your own curing process, you’ll find the results speak for themselves.

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