I have now jarred all the weed from my 4x4 grow, all of it dried and cured in the new dryer. As far as I can tell, and I do not pretend to be an expert, the finished bud from the dryer set at the recommended 57%RH and 68F is perfect. Some came out after the recommended 8 days total, some as long as ~15 days, and it made zero difference that I can detect. It is all pleasant odor, zero grass, the texture is perfect, and when ground nice and soft and sticky. I will not process my weed any other way now. Good bye burping jars and trying to control the dry in paper bags. Also good bye to Grove bags - they work after a fashion, but I have over dried bud in them, and although I have not tested to confirm, I think they are just overpriced and relabeled bags used for commercial sale of other products that need moderate protection from getting too dry on the shelf.
All told, I processed something like 800 grams dry, done in staggered batches as each plant was chopped, or several pounds wet, you do the arithmetic. I am sure that the dryer would have handled the entire load even if it all went in at the same time. When a load was added, the cycling by the RH control would immediately start cycling every ten seconds or so, and this would continue for a day or so before the cycling gradually reduced back to once every 10-20 minutes or so. After initial testing, I just left the humidifer tray in place, and it would take over as needed once the bud got too dry to keep the RH up on its own. At no point did the extraction fan come on continuously, As far as I noticed, it never ran for more than 10-15 seconds before stopping for the next cycle, even in response to a fresh load being added. Cycling due to temperature dropping was very infrequent, likely due to the fact that I built the dryer out of styrofoam insulation.
The following sections will summarize for peeps who may wish to build their own dryer.
1. Minimum gear needed:
The following items are required whatever the details of the final design. In the next section I expand on variations that can be considered:
- RH controller: I used the Inkbird ITC-608T and highly recommend it. The sensitivity of the RH sensor is wonderful, response is in seconds if the sensor is in moving air. Speed of response is important because it will determine how much overshoot happens past the setting for RH. This one does both RH and temperature, but the only one really needed IMO is RH. More on this later.
- An airtight containment: I made mine out of styrofoam insulation, and it worked perfectly. The insulation resulted in very slow change in temperature (my "lung room" was always cooler than 68F, usually less than 65F, but not by much.
- An extraction fan: In order to regulate RH at the intended level, the containment must have a fan of some sort which when turned on by the RH controller removes humid air from the containment and draws drier outside air in to replace it. I used a squirrel cage fan salvaged from a water heater, but any inline duct fan would likely do the job.
- Valved intake and extraction openings: The intake and extraction holes need to be valved somehow so that they close reasonably well when the extraction fan turns off. I used ping pong balls inside ABS fittings which was effective and cheap. Even some sort of flap valve might work. The degree of seal will determine how often the extract fan has to extract air, and may make a difference in odor escape if that is an issue.
- An air circulation fan: In order to control the process, the air inside the containment must be kept moving. I used a computer fan driven by a 12 volt charger adapter that I had in the stash.
- An internal humidity source: As the bud dries, eventually it will not be able to keep the RH high enough, so some sort of internal humidity source must be included. Mine was a small tray with cellulose sponge and water in it. Whatever is used, it must be exposed to the air being moved inside the dryer.
2. Other construction considerations and options:
- Shelving: If bud will be dried as trimmed and broken down as mine was, the containment will need as many shelves as needed for the biggest load intended, spaced as far apart as needed to accommodate the largest cola/nug intended to be processed. If drying hanging branches rather than trimmed bud, whatever means needed for hanging them will need to be included.
I made my shelves out of a wood frame with aluminum screen. If more cost is ok, they could be constructed with aluminum frame material normally used for removable window screens. If cost needs to be minimized, I believe that heavy cardboard cut from appliance boxes could do the job as long as the shelf size is small enough to support the load, and the setup allows free air movement between all shelves. I preferred the aluminum screen because it can be cleaned wet, unlike cardboard, it was a lot cheaper than sourcing aluminum framing, and it allowed air to move through it.
- Containment material: I built my containment from scratch out of styrofoam. I considered plywood, but avoided it due to the risk of off gassing from the glue or wood used. An old fridge would do very nicely, but I didn't have one, or a place to put one when not being used. It is possible that even installing cardboard shelves inside a cardboard box might suffice. I tried an appliance box and the same Inkbird to dry hanging branches last year, but it didn't work primarily because after about 24 hours RH dropped too low and I had no means of raising it. What I like about styrofoam is that it insulates, it does not offgas anything (at least not to my nose), it is easy to work with, has sufficient structural strength for the job, and is relatively easy to glue together in whatever configuration needed.
- Internal air circulation: Moving air over all bud in the dryer at more or less similar rates should result in the most even drying possible. That is why my dryer has a separate upper air mixing chamber, and side chambers from which air is passed through holes that direct air over every individual shelf. I used a single high output computer cooling fan to extract air from the drying chamber, blow it into the mixing chamber where incoming air enters, the humdifier tray adds humidity, and the blackened light bulb adds heat as needed. Once mixed, the air moves down into the side chambers, and from there into the drying chamber.
I suspect that my air circulation design is overkill (of which I have been accused more than once
). Less even air movement will simply mean that some bud dries quicker, but since it is impossible for any bud, or even any portion of an individual bud to overdry, that harms nothing. As I mentioned, being in the dryer for anything from 8 to ~15 days seemed all the same to me, and Cannatrol actually says that their units can be used for storage. Bottom line here seems to be that any fan arrangement will suffice as long as it keeps air moving everywhere in the dryer.
The other detail with air circulation is that the temperature and RH sensors need to be in moving air, but not directly in the stream of incoming replacement air. Cycling will be minimized by making sure that the sensors are in moving air, the more vigorous the better, but placing it in the incoming air may result in odd behaviour by the controller. The sensors need to read more or less what the bud sees, not what the lung room provides. I placed mine in one of the side chambers where mixed air moves to the holes that directed air over the shelves.
- Temperature control: I used a blackened 40 watt light bulb controlled by the Inkbird to keep the dryer at 68F, and that worked perfectly in my setup. A less insulated containment might need more power, depending on lung room temperature and the processing temperature needed. However, in principle, there may be no reason for temperature control as long as the dryer is used at a normal room temperature. The difference is likely just that higher temperature mean a faster dry, but keep in mind that overdrying cannot happen as long as the RH is on target. My design depends on the lung room being cooler than the intended dryer temperature. If the lung room would otherwise be too warm, air conditioning would be needed.
- RH control: The operation of my dryer also depends on the lung room being at an RH lower than that needed in the dryer. This means that it will not work at higher humidities unless the lung room has dehumidification. Since RH in winter where I live, and that is the only time I process weed, this limitation was ok by me.
That's it peeps, if there are any questions, post them in the blog so that answers will be found easily by other growers. I will edit as needed if I think of anything that needs it.
All told, I processed something like 800 grams dry, done in staggered batches as each plant was chopped, or several pounds wet, you do the arithmetic. I am sure that the dryer would have handled the entire load even if it all went in at the same time. When a load was added, the cycling by the RH control would immediately start cycling every ten seconds or so, and this would continue for a day or so before the cycling gradually reduced back to once every 10-20 minutes or so. After initial testing, I just left the humidifer tray in place, and it would take over as needed once the bud got too dry to keep the RH up on its own. At no point did the extraction fan come on continuously, As far as I noticed, it never ran for more than 10-15 seconds before stopping for the next cycle, even in response to a fresh load being added. Cycling due to temperature dropping was very infrequent, likely due to the fact that I built the dryer out of styrofoam insulation.
The following sections will summarize for peeps who may wish to build their own dryer.
1. Minimum gear needed:
The following items are required whatever the details of the final design. In the next section I expand on variations that can be considered:
- RH controller: I used the Inkbird ITC-608T and highly recommend it. The sensitivity of the RH sensor is wonderful, response is in seconds if the sensor is in moving air. Speed of response is important because it will determine how much overshoot happens past the setting for RH. This one does both RH and temperature, but the only one really needed IMO is RH. More on this later.
- An airtight containment: I made mine out of styrofoam insulation, and it worked perfectly. The insulation resulted in very slow change in temperature (my "lung room" was always cooler than 68F, usually less than 65F, but not by much.
- An extraction fan: In order to regulate RH at the intended level, the containment must have a fan of some sort which when turned on by the RH controller removes humid air from the containment and draws drier outside air in to replace it. I used a squirrel cage fan salvaged from a water heater, but any inline duct fan would likely do the job.
- Valved intake and extraction openings: The intake and extraction holes need to be valved somehow so that they close reasonably well when the extraction fan turns off. I used ping pong balls inside ABS fittings which was effective and cheap. Even some sort of flap valve might work. The degree of seal will determine how often the extract fan has to extract air, and may make a difference in odor escape if that is an issue.
- An air circulation fan: In order to control the process, the air inside the containment must be kept moving. I used a computer fan driven by a 12 volt charger adapter that I had in the stash.
- An internal humidity source: As the bud dries, eventually it will not be able to keep the RH high enough, so some sort of internal humidity source must be included. Mine was a small tray with cellulose sponge and water in it. Whatever is used, it must be exposed to the air being moved inside the dryer.
2. Other construction considerations and options:
- Shelving: If bud will be dried as trimmed and broken down as mine was, the containment will need as many shelves as needed for the biggest load intended, spaced as far apart as needed to accommodate the largest cola/nug intended to be processed. If drying hanging branches rather than trimmed bud, whatever means needed for hanging them will need to be included.
I made my shelves out of a wood frame with aluminum screen. If more cost is ok, they could be constructed with aluminum frame material normally used for removable window screens. If cost needs to be minimized, I believe that heavy cardboard cut from appliance boxes could do the job as long as the shelf size is small enough to support the load, and the setup allows free air movement between all shelves. I preferred the aluminum screen because it can be cleaned wet, unlike cardboard, it was a lot cheaper than sourcing aluminum framing, and it allowed air to move through it.
- Containment material: I built my containment from scratch out of styrofoam. I considered plywood, but avoided it due to the risk of off gassing from the glue or wood used. An old fridge would do very nicely, but I didn't have one, or a place to put one when not being used. It is possible that even installing cardboard shelves inside a cardboard box might suffice. I tried an appliance box and the same Inkbird to dry hanging branches last year, but it didn't work primarily because after about 24 hours RH dropped too low and I had no means of raising it. What I like about styrofoam is that it insulates, it does not offgas anything (at least not to my nose), it is easy to work with, has sufficient structural strength for the job, and is relatively easy to glue together in whatever configuration needed.
- Internal air circulation: Moving air over all bud in the dryer at more or less similar rates should result in the most even drying possible. That is why my dryer has a separate upper air mixing chamber, and side chambers from which air is passed through holes that direct air over every individual shelf. I used a single high output computer cooling fan to extract air from the drying chamber, blow it into the mixing chamber where incoming air enters, the humdifier tray adds humidity, and the blackened light bulb adds heat as needed. Once mixed, the air moves down into the side chambers, and from there into the drying chamber.
I suspect that my air circulation design is overkill (of which I have been accused more than once
). Less even air movement will simply mean that some bud dries quicker, but since it is impossible for any bud, or even any portion of an individual bud to overdry, that harms nothing. As I mentioned, being in the dryer for anything from 8 to ~15 days seemed all the same to me, and Cannatrol actually says that their units can be used for storage. Bottom line here seems to be that any fan arrangement will suffice as long as it keeps air moving everywhere in the dryer. The other detail with air circulation is that the temperature and RH sensors need to be in moving air, but not directly in the stream of incoming replacement air. Cycling will be minimized by making sure that the sensors are in moving air, the more vigorous the better, but placing it in the incoming air may result in odd behaviour by the controller. The sensors need to read more or less what the bud sees, not what the lung room provides. I placed mine in one of the side chambers where mixed air moves to the holes that directed air over the shelves.
- Temperature control: I used a blackened 40 watt light bulb controlled by the Inkbird to keep the dryer at 68F, and that worked perfectly in my setup. A less insulated containment might need more power, depending on lung room temperature and the processing temperature needed. However, in principle, there may be no reason for temperature control as long as the dryer is used at a normal room temperature. The difference is likely just that higher temperature mean a faster dry, but keep in mind that overdrying cannot happen as long as the RH is on target. My design depends on the lung room being cooler than the intended dryer temperature. If the lung room would otherwise be too warm, air conditioning would be needed.
- RH control: The operation of my dryer also depends on the lung room being at an RH lower than that needed in the dryer. This means that it will not work at higher humidities unless the lung room has dehumidification. Since RH in winter where I live, and that is the only time I process weed, this limitation was ok by me.
That's it peeps, if there are any questions, post them in the blog so that answers will be found easily by other growers. I will edit as needed if I think of anything that needs it.