This is my sop (without getting into minute details) it really only is efficient for 100+ grams of thc-a otherwise there is a significant loss
might be a little off but it will at least give you some starting points .
steps 1-6 are to purify thca to levels needed for clean ,big , easy to make crystals skip these steps and move onto step 7 if you feel your thc-a is already pure enough 90%+/-
feel free to add any advice fam. bless up
#1 separate ht from hc
#2 break up hc in uniform sand like grain
#3 add small amount of pentane to jar around a cm or less covering the bottom i like qt jars
#4 feed hc into jar slow agitation swoosh liquid around in jar you will see it start to pull the unwanted parts of the thc-a out. keep pentane in liquid state if becomes oil like viscosity add a small amount of pentane too much and you will dissolve thc-a too little and you will not be dissolving the unwanteds anymore
#5 if top liquid pentane layer is too dark and crystals on the bottom are not close to pure white let the thca settle, slowly pour off/siphon off top layer, try to stop if you see some thc-a grains coming with it.Now If liquid layer is light in color with a water like viscosity proceed to buchner funnel filtration. if not add small amount of pentane ( a few mls) untill you see a close to white color in the thca layer dont add too much ! you will dissolve more thca than wanted
#6 filtering: pour slurry into buchner funnel after filter is ready and set. add pentane (-20 -50c seems to work best) too cold and you wont dissolve undesireables too hot you will dissolve too much thca .too much pentane will dissolve too much thca as well , too little wont dissolve enough
*if you are left with dark chunks in your pure thca seperate these out repeat steps #4+
*A strainer works well for seperating the rather pure thc-a from the chunks
#7 once you are able to obtain yout purified thca granules (90%+/-) re dissolve into new pentane hotplate in safe area with minimum heat <90f .try to use as little as possible as needed or it will take longer example (77 grams in 300 ml pentane)
#8run dissolved liquid into coffee filter back into a clean jar this is to prevent unwanted seeds from starting
#9(room temp)
slowly evaporate pentane untill desired saturation level is obtained you can check this by throwing a few test seeds in the pentane if they dissolve too fast you need to evaporate more if they dissolve slowly or remain their same size you are close. If they are growing slowly this is the ideal saturation level.
#10 add big seeds( at this time your saturation and purity levels should be ideal.)
keep in mind evaporate too fast at this time and you will get unwanted contaminants trapped in the crystal lattice you want to evaporate reaaal slowy but not just sitting there or it will pause the process ( crack a ball jar lid as little as possible)
#11 if small unwanted seeds start to appear over time isolate wanted seeds repeat step #7 and up
#12 once pentane gets to the point where your crystals are not covered or your impurities are getting too concentrated ,remove the wanted seeds then fast crash the pentane solution by keeping the lid off repeat steps #4+ once solution has evaporated the pentane leaving unwanteds+ THC-A