Making bubble hash with a Harvest Right freeze dryer will completely change the way you make rosin. It is the difference between a dark, sticky oxidized goo and a bleach blonde fluffy hash just waiting to be sifted and pressed into hash rosin.
How a Freeze Dryer Works
- Wet bubble hash is placed in the freeze dryer where it is frozen solid.
- Once frozen, the freeze dryer creates a vacuum in the chamber.
- Water sublimates out of the hash and re-condenses on the inside of the chamber
Sublimation is the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage. This is the key behind drying out your hash without any oxidation.
Does Oxidation of Hash Impact Taste?
A reddit discussion recently asked a great question. Does freeze drying hash impact the taste or is it simple for aesthetics (i.e. is lighter hash better tasting, or does it just look better?
The apple analogy is one we often use in the cannabis industry when discussing trichomes because the skin of an apple offers similar protection from oxidation to what the waxy shell of a trichome head does for the terpenes inside. Just like hop forward beers (which are high in hop terpenes), cannabis terpenes have a short shelf life. Even worse is that once these terpenes oxidize they turn brown and leave behind a bitter foul taste.
So yes- freeze drying will typically improve the taste of your hash as the byproducts of oxidation negatively impact flavour. That being said air-dried hash done properly can be an amazing thing. Especially if your end product is melt and not rosin. See this post for more info on air drying vs freeze drying.
Which Model of Freeze Dryer For Bubble Hash
To make hash you will need a one of the Pharmaceutical Grade Harvest Right freeze dryers. They have shallower trays than the units intended for food and have more granular control over shelf temp.
The food grade freeze dryers run too hot and will bake your hash. Avoid these. You can freeze dry food in a pharmaceutical grade freeze dryer but you can’t freeze dry hash in a home grade freeze dryer.
I have the smallest unit they offer with the free vacuum pump that comes standard. We run the oil-less (dry scroll) pumps at work… they are worth the upgrade if you can afford it as they run quieter and don’t require oil changes. That being said the stock oil pump is fine for most home use.
Harvest Right Freezer Setting for Hash
Go to Custom Setting on your Harvest Right Freeze Dryer and input the following as a starting point:
Shelf Temp: 0-45 F
Final Dry: 1:00-24:00
The default shelf temp setting of 55F is a bit too hot for hash, especially since the units run a bit warmer than the preset temp. If you ever get hard chunks in your hash there is a good chance you baked your hash with too warm of a shelf temp during the thaw cycle.
We prefer low shelf temps (0F – 5F) for maximum terpene preservation and small batches. When running large batches increasing shelf temps may be necessary to speed up the process in a production enviornment.
Do not Over-dry your Hash
While it is critically important to properly dry the hash to make sure there is no frozen water chunks remaining, you also do not want to over-dry the hash. Over drying hash can pull off terpenes and leave you with a dry rosin.
If you are never finding hash with some chunks of water in it when you check your hash there is a good chance you are over drying your hash. If you are close to the line sometimes you will end up before it.
Tips For Making Bubble Hash with a Harvest Right Freeze Dryer
My biggest tip is to not use the “defrost mode” at the end of a drying cycle. When the freeze dryer is done there will be a bunch of ice in the chamber that has sublimated out of the hash and frozen to the chamber. The unit’s defrost mode blasts the shelf heating trays at max temp melting the ice in an hour or so. While this is fine when you’re dehydrating fruits/veggies, any trichomes that might be in the chamber will bake onto the trays and heating mats. This will make cleaning the unit out a huge pain.
To defrost the unit I simply turn it off and allow it to defrost slowly with the door open. The water will slowly drain out into a bucket via the hose.
Another tip is to insert a few shims under the front two feet during the thaw cycle. This will keep water from coming out of the front of the unit during thawing. You will want to remove the after as it helps to have the unit be level when inserting trays of wet hash into it.
When breaking the vacuum always go slowly. This will prevent a fast air current from blowing your hash all over the freeze dryer.
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