Bud dryer - manicured to smoke in 3 days

Having buds hanging around air-drying for a long time is a security problem. I cooked up a bud dryer to speed up the process.



I first looked at commercially available food dehydrators, but they usually operate at 38C/100F or above. Too hot! THC starts to break down at about 29C. So, I set about making my own.

This one goes just 3 days from manicure to smoking, removing moisture so quickly that there's no possibility of mould.

It's a plastic storage box with 4 wiremesh racks hanging on open-link chains from the lid.



There is one 5" muffin fan on one end sucking air out of the box



and another fan drawing air into the box.



I have a big deep-finned aluminum heatsink bolted to the 4" fan so air is drawn through the heatsink fins and blown into the box.



There's 2 aluminum-bodied 470 ohm, 25 watt power resistors bolted to the heatsink. Temp control is by a standard incandescent light dimmer which controls power to the resistors which are wired in series.



I adjust the light dimmer control until the air temp is no more than 29C as THC begins to break down at temps any higher. It is best when first firing up this design to start at the 'off' point on the dimmer and increase the power to the resistors slowly, in 1/10 of a turn increments. You don't want to open the dimmer all the way up as it may overcurrent the resistors. If I built this over again, I'd probably increase the value of the power resistors to 1.2-1.5k ohms, but these are what I had on hand at the time!


(note thermometer temp sensor placed in the warm airflow)

This tiny bit of added heat drops the ambient air humidity enough to allow it to pick up the water out of the buds very quickly as it passes through the box. Just warming the ambient air a few degrees will reduce the relative humidity dramatically.

Buds are totally dry and ready to smoke in 3 days rain or shine, but if ambient relative humidity is very high, 80% or so, drying time can stretch out to 4 days.

The dryer CAN overdry buds if I'm not careful, but that's solved by putting a teaspoon of water on a paper towel and nesting it in the buds for a couple of hours until they are nice and springy again.

There is a UV ioniser placed a few feet away from the dryer to kill scents, but the high volume of airflow through the dryer itself does a lot to reduce that musty, dank perfume.

This old dryer is cracked, beat-up, covered in resin goo, was really only a prototype I never got around to building properly- and is generally filthy. But the damn thing works and keeps working. Moreover, it's usually in constant service and has been for about 5 years.

There's dozens of ways to build this- almost anything similar will work. Just mind the current you throw into the resistors and keep a close watch on the air temp coming from the warmer- hold it to 29C.

oh, i bet that weed just taste sooooooo yummy. crumbs up real nice. i know a guy that would love this.

this looks good but, is the weed still of same quality? i know thc levels wont be effected but is taste and/or the bud itself any different?

very neat setup, I think I will cobble together something similar

fdd2blk said:

oh, i bet that weed just taste sooooooo yummy. crumbs up real nice. i know a guy that would love this.

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Taste is just the same as hang dried except that there's no possibility of mould... and I really hate the taste of mould- and can pick it up in tiny amounts. The humidity around here is often so high that hang-drying can take a couple of weeks, meaning there's always a tiny hint of mould in my hang-dried buds.

The texture of buds run through my dryer is no different to hang-dried. I dry them until there is just a little bit of springyness left in the buds, not quite to the point where they crumble or break apart.

Keep in mind that my homebuilt job doesn't heat to the high temps used in normal food dehydrators. Weed dried in a food dehydrator WILL come out harsh, crumbly and overdried because food dehydrators are too damn hot.

I thought about modifying the heating element in a regular food dehydrator to cool it down, but then I went shopping for one- and found they get $150-250 for a new dehydrator! I built my own for under $40, might have cost a bit more if I had not pulled some stuff out of my junkbox for it. The biggest food dehydrator I could find was also less than 1/3 the size of my jerry-rigged dryer.

mogie said:

Very impressive.

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Thanks, mogie. You're being very kind to my slacker engineering efforts!

bigbudeddie said:

this looks good but, is the weed still of same quality? i know thc levels wont be effected but is taste and/or the bud itself any different?

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The stuff that comes out of this dryer is nicer than hang dried as it can't possibly have any mould.

You can vary the smoking smoothness of any buds by varying how much water you leave in the buds. Slightly moist buds smoke smoother because they burn cooler.

It's possible to overdry with my dryer, but as said before, it's very easy to put a little water back in by nesting a paper towel with a teasoon of water in the buds for an hour or two.

fnord said:

very neat setup, I think I will cobble together something similar

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Thanks. It's very easy to make something that works well.

Would recommend that if you use a plastic storage tub, use a 'hot knife' to cut the holes for the fans. A jigsaw will crack and shatter the cheap plastic. You can make a hot knife by hammering a soldering iron tip flat. Will melt nice neat bolt holes and cut the large circles with ease.

If you find that the 25watt power resistors are too expensive (about $15 each but free for this project out of my junkbox), you can use a 25-30 watt soldering iron element firmly clamped to the heatsink instead. I've seen soldering irons for $7-10.

Al B. Fuct said:

it's usually in constant service and has been for about 5 years.

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correction... I just found an old photo of this dryer in operation back in 2000- it has been in use for 7 years.

I don't even want to know how much dope this thing has processed! It would be a whole lot!

I've had as much as 16oz dry weight come out of it in 3 days, all racks loaded to capacity in a single layer.

all right i'm an old school 2 week cure kinda guy. but the hot knife now that's something i can use. thank you.

Nothing wrong with the 2-wk cure as long as you have reliably low-humidity ambient air to dry it in. Rains a lot here, so I needed to make my own low-humidity air.

So it happens, a dryer is faster than hang drying and the air motion alone suppresses mould. Because I'm limiting temp to 29C/84F, this dryer is not much different than hang drying on a warm, dry, windy summer day. It's worlds different from a commercial food dryer at ~100-140F.

The hot knife thang is a good trick. Definitely an outdoor job, tho. The plastic smoke is wicked. If you're clever, you can wire a dimmer into a power outlet strip and use that to vary the temperature of the soldering iron element to reduce smoking.

Al B. Fuct said:

Nothing wrong with the 2-wk cure as long as you have reliably low-humidity ambient air to dry it in. Rains a lot here, so I needed to make my own low-humidity air.

So it happens, a dryer is faster than hang drying and the air motion alone suppresses mould. Because I'm limiting temp to 29C/84F, this dryer is not much different than hang drying on a warm, dry, windy summer day. It's worlds different from a commercial food dryer at ~100-140F.

The hot knife thang is a good trick. Definitely an outdoor job, tho. The plastic smoke is wicked. If you're clever, you can wire a dimmer into a power outlet strip and use that to vary the temperature of the soldering iron element to reduce smoking.

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it just keeps getting better. i actually have a dimmer box i just plug into. thaks again. + rep.

...and for my next trick... free beer from plant trimmings!

Happy to be of service.

I like it, i have plenty of fan's, and plenty of tub's i think im going to make a quick dryer.

Very nice. I've been thinking of a very similar design for a drying box using a wood box and chicken wire baskets. The drying process would be even faster due to the porus nature of wood and depending on the wood used it could leave a great scent behind.

The one I was going to make would be built out of mosquite wood that has been charred slightly over a fire on the inside. This will produce a peppery taste as well as significantly reduce the odor.

TillthedayiDIE420 said:

I like it, i have plenty of fan's, and plenty of tub's i think im going to make a quick dryer.

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Why not? All the bits in this are fairly cheap and available if you don't have most of them already. When you've gotten some buds out of your new dryer, drop back in and tell us what you find about any difference between hang-dried and that done in your dryer. If you keep the air temperature at or below 29C/84F, there really should be no difference, except that there won't be any mould in the stuff you do in the dryer.

Godkas said:

Very nice. I've been thinking of a very similar design for a drying box using a wood box and chicken wire baskets. The drying process would be even faster due to the porus nature of wood and depending on the wood used it could leave a great scent behind.

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The porosity of the box will be insignificant in removing moisture from buds compared to the slightly warm airflow through the box. A plastic box will not only do fine but is probably preferable for this application, if only for the ease of building the thing.

Godkas said:

The one I was going to make would be built out of mosquite wood that has been charred slightly over a fire on the inside. This will produce a peppery taste as well as significantly reduce the odor.

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I wouldn't count on any scent reduction or adding of the mesquite scent to the buds. If you use fans like mine, there's so much air moving through the box that the scent of the mesquite will be dissipated, as is the scent from the buds themselves. I'm also not sure I would want any foreign flavours in my buds, but that's just personal preference.

If anyone is actually going to build a copy of this, I probably ought to make some notes on usage.

One thing that I found out early on is that buds can be 'false dry,' meaning the outside of the buds can feel very firm, almost crisp, but the inside may yet still be fairly wet. If the buds are taken out and bagged at this stage, the moisture will migrate to the outer layers and the buds may in several hours be too soft and damp. Buds can appear to be 'false dry' in this manner after about 40-50 hours in the dryer (depending on ambient temp & RH). I test the moisture content by how readily the stems in the buds snap.

With practice, you will learn the exact time to remove and bag your buds to get the moisture balance spot on for storage and smoking. Overdry buds store well but are harsh to smoke. Overdamp buds smoke smoothly (way too wet means it's hard to light), but can develop mould in storage.

I tend to err on the side of overdry because it's easy to reverse the process and add a little moisture back in by putting the buds in a plastic Tupperware type container for a couple of hours with a slightly dampened paper towel.

If/when I ever get around to rebuilding this thing, I don't think I'd hang the wire racks from the lid. This arrangement means you have to hold the lid/racks up in the air with one hand while loading or emptying the racks with the other.

I have seen some ultra-cheap stackable plastic storage racks in the dollar shops, with their own plastic tube legs which press-fit into the 4 corners of the racks. One could get racks which closely fit inside a tub. The thing would be much easier to load and unload with racks which stand up on their own instead of hanging from the lid.

im sure of the smell and flavor changes. Anything in a charred smokey box smells and even tastes like the wood it is stored in (provided that wood has a transferrable taste) regardless of relative airflow

OK, make one out of wood and let us know how you go. I have a feeling the large amount of ventilation will blow the wood scent out, but I haven't tried it.

Al B. Whats up. We built a dryer in a a container about the same size. with 2 fans, 125 cfm total, on each end sucking air out. and 13 total holes to bring air in . Do you think that there are enough holes? then we put 3 wire clothes hangers about 8 inches apart to lay the stalks on. everything is spaced out evenly to dry. how long do you think it will take to dry?

If you are not warming the air and don't have a cross-flow, it should take only somewhat less time than it takes to hang-dry. However, any air motion will reduce the possibility of mould getting a foothold.

I find that a cross-flow through the box, in one end, out the other, is more effective than trying to either just blow air in or out.

Pass #1 on my dryer only had 1 fan, pumping warm air in, with unaided exhaust. Adding the exhaust fan speeds it up dramatically.

FYI on dehydrators: Commercial Food, Fruit, Beef Jerky Dehydrator & Dryer - Drying Herbs & Fruits – Excalibur Dehydration

I have the same security issues. My solution: buds drying in between newspapers in the oven. 10-14 days.