STORAGE

How should I store my hash? How you store your hash depends on your desired outcome. Hash and rosin are complex substances with various attributes to preserve or enhance. While I can't provide a universal storage solution, I can explain storage factors and potential outcomes to consider when selecting a storage solution.

If I am trying to preserve my product as it was when packaged, I will select a zero headspace or inert headspace environment and a temperature that promotes the material remaining in its current state. Cold temperatures decrease solubility and promote separation. Additionally, they slow down chemical reactions. Warmer temperatures accelerate molecular movement, influencing texture, and increasing solubility. Finding the ideal temperature balance to maintain specific textures is crucial. Due to the complex and varied nature of hash and rosin, custom storage solutions may be necessary.

What is headspace?  Headspace is the area above your material inside the container.  If there is head space not occupied by gases from the volatiles that head space will continue to fill up with gases from the volatiles until that space is saturated.  Once that space is fully occupied volatiles will stay in the matrix.  When you open the container those molecules go into the surrounding air and when the container is capped more volatiles can enter that head space.  Each time the container is opened it promotes more volatile loss.  Reducing the headspace in the container will help retain volatiles in your hash or rosin.

I have head space in my container, can I adjust the humidity to protect the volatiles?  Short answer, yes: water vapor acts like a traffic jam for volatiles. Raising humidity or water activity (aw) around hash slows the diffusion, evaporation, of terpenes and other VOCs.  Terpenes are lost mainly by gas-phase diffusion.  High humidity does two things: thickens the boundary layer at the surface, and reduces effective diffusion coefficients for terpenes in air, resulting in slower terpene escape.  Water vapor displaces terpene partial pressure, in dry air there is "room” for terpene molecules.  In humid air, water vapor occupies a large fraction of the gas phase, partial pressure available for terpenes is reduced, and they escape more slowly.  

At moderate aw around 0.55–0.65, trichome resin is less brittle, the gland wall lipids stays plasticized.  At this water activity range terpenes remain more strongly partitioned into the resin.  At very low aw <0.3, the resin becomes glassy, micro-fractures form, and terpenes escape faster.  

There is a sweet spot, above 0.7 aw, there is microbial growth risk, enzymatic activity increases, and terpene loss occurs via biochemical pathways.  

What is the best humidity range or water activity range for perserving volatiles in the matrix?  The optimal terpene retention zone is aw around 0.55–0.62 or RH around 58–62% (equilibrated).  Keep the temp cool and the oxygen minimized.