The Art of the Long Cure
Curing cannabis has many benefits. In addition to allowing for a longer shelf life as the name implies, curing cannabis also has a tendency to significantly mellow out any harsh notes, and overall improves flavor and aroma significantly. Cannabis that was improperly cured can smells like hay or grass, or worse yet may smell of ammonia.
What’s that smell?
Ammonia smells can develop when cannabis is stored in too humid of an environment, it is evidence of anaerobic activity and is a harbinger of mold, or worse. If you just have a hint of ammonia smell, your bud likely needs “burped”, or allowed to air out with plenty of circulation for an hour or so at a time. If the ammonia smell is overwhelming, it may need disposed of.
Grassy/hay smells are indicative of cannabis that was dried too quickly. When cannabis is rapidly dried, it locks in a lot of unpleasant chlorophyll, which is very apparent in the aroma. This chlorophyll smell will often overtake any semblance of terpenes, leaving you with much harsher flower. A rapid dry can also actively break down/destroy terpenes, which are very sensitive to heat and light.
So how do we avoid both of those awful smells (hey grass smells nice, but not in my weed!), and get cannabis that smells just as good as—or even better than—the top-shelf ½ ounce from the dispensary? Let’s dive in…
Day One: Harvest
You just put several months of work into raising some fine plants, and today is your reward! You get to cut down your latest round of flower. Now begins the process of turning this live plant full of water, in to something just a bit “wetter” than your average 2×4. (Don’t worry, that will make sense later…)
Start by plucking off the fan leaves from your plant. Don’t worry about taking of any sugar leaves or questionably small fan leaves right now. If you have smaller plant(s) and/or it is practical to hang them whole, do that. Otherwise, break the plant(s) down into manageable chunks. There’s really no wrong way to hang your plants, just make sure they can get plenty of airflow on all sides.
Week One: Initial Dry
Depending on the RH and airflow of your drying room/enclosure, it may happen sooner or later, but when your buds very first start to get “crispy” (even a little!) start checking their moisture content every 12 hours with a moisture meter set to “Wood”. We are looking for their water content % (by weight) to get down to 13%.
This might happen in as little as a week, or it may take several depending on your RH. A bit on the slower side is better, but always be vigilant of mold.
Week Two: Secondary Dry
It is likely that by 2 weeks after harvest your flower will be at or below 13% water by weight, we highly recommend you check this with a moisture meter though. At this point, cut down your plants further to fit them into brown paper bags. Loosely stack your material, avoiding overcrowding the bags. Put a hygrometer* in each bag, and monitor them at least once a day, several times if you can. We are looking for the RH of the bags to come down to 60%, but again this should not be rushed.
* We recommend analog hygrometers since they can be easily calibrated, and typically only larger/more expensive digital variants can be calibrated.
Week Three: Trim
Once the internal RH of your paper bags come down to 60% it’s time to trim your bud (or not). You can use an automated trimming setup, hand trim with fiskars, or leave it au naturel, your choice. We like to do a tight trim at this point to remove as much chlorophyll rich material as possible while leaving trichomes in tact.
Week Three: (Still) Curing Begins!
Once your bud is trimmed, we need to keep it at 60-62% RH for well… ideally until it is consumed. There are a couple methods to achieve this. If you have a smaller harvest of less than 1 lbs. you might choose to put your flower in glass jars with at least 30% headroom. Each jar should have a hygrometer and/or a 2-way humidity pack, and will need burped at least daily. The first week or two the jars may need several burpings a day. Any chance you get, rotate the jars so the flower inside can mix around and dry more evenly.
If you go with jars, it is imperative you size your jars and humipacks appropriately. As a general rule of thumb, a you can fit about 1 oz. of bud for every 16 fl. oz. of glass jar, but er on the side of a little extra-spacious as opposed to over-crowded. The manufacturer of your humipack will have weight specifications for usage.
If you have a larger harvest, or just don’t want to babysit 14 glass jars of weed, you might consider using something like a Grove bag. These bags branded as “Terploc” use a semi-permeable membrane, specifically engineered for cannabis, that will keep your flower right in the perfect humidity range for safe long term storage.
Source: SpongeBob
Week Eight: Basic Cure Finished
At this point your bud has officially been curing from anywhere between 35 and 45+ days. Most flower will still see improvement from further curing, but returns will be diminishing from here on out.
Week Nine+: Artisinal Cure
If you did your initial cure in jars, we recommend checking your humipacks for replacement at this time. If you did your initial cure in Grove bags, you’ll need to transfer into jars with humipacks now. Grove bags keep product at a safe 50-55% RH, which is great for long-term storage, but is a bit too dry for long-term curing. Fortunately at this stage burping should no longer be needed. Just make sure to replace your humipacks as needed.
There are several options for 2-way humipacks. We’ve used Boveda in the past with great results, but we’ve also seen Integra used by many medical/recreation brands and they seem to work well too.
How long you continue to cure at this point is up to you. I personally have not noticed a difference between a 3-month cure and a 6-month cure, but there is a stark difference in aroma & palatability between a plant that was cut down a month ago, and a plant that’s slowly dried for 2 weeks & carefully cured for 3 months.
It is a significant time commitment, considering most any modern strains would be germinated, fully grown, and harvested in that time period. However, once you are growing your own cannabis, if you find you enjoy it, you’ll likely end up harvesting enough that experimenting with new processing techniques like long-curing or rosin tech makes sense for you.