I know this may have been done to death, but this is how I do it. If time is not a concern, it sure saves wear and tear on the pump, and it is a very low maintenance method.
Clean safrole:
Go get a three liter bottle of cheap white zinfandel.
Invite some friends over - kill the wine, save the bottle.
Pour three liters of primo quality sassy into the empty wine bottle.
Put the bottle sassy in the fridge.
Pour a couple of ounces of sassy in a clean mason jar.
Put the sealed mason jar in the freezer.
Sharpen a carving knife real well; especially the tip.
Put the sharp knife in the freezer along withe the jar of sassy.
Go get a set of tweezers.
Put the tweezers in the freezer along with the sharp knife and jar of sassy.
Wait one day.
Open the freezing cold mason jar and scratch inside the bottom of the jar with the tip of the knife.
Watch in amazement as the bottom of the jar becomes a solid crystalline mass.
Place the jar on the kichen counter for 20-30 minutes and let 2/3 of the crystals melt.
Place the sealed mason jar back into the freezer.
Wait one hour, returning to find the jar now has some larger clearer crystals on top (seed crystals).
Using the cold pair of tweezers, pluck one of the seed crystals out of the mason jar, and drop it into the cool wine bottle of sassy.
As soon as the crystal breaks the surface, it starts bursting with crystals - resembling some kind of fractal art.
Put the wine bottle back in the fridge.
Wait four days.
Notice the crystals have pushed the impurities to the top. The unfrozen liquid resembles a dark yellow urine color.
Put the wine bottle in the freezer.
Wait two days.
Take out the wine bottle, open it up, and pour the yellowy unfrozen crap into another mason jar. This is mostly crap; very little safrole left here- but save it for now anyway. Put it in the freezer.
Leave the wine bottle full of crystals out on the kitchen counter for about ten hours.
After it is almost completely melted except for a few crystals at the bottom, put it back in the fridge.
Wait four days.
Put the wine bottle in the freezer.
Wait two days.
Take out the wine bottle, open it up, and pour the yellowy unfrozen liquid into the "crap" jar.
Leave the wine bottle full of crystals out on the kitchen counter for about ten hours.
After it is almost completely melted except for a few crystals at the bottom, put it back in the fridge.
Wait four days.
Take out the wine bottle, open it up, and pour the yellowy unfrozen liquid into the "crap" jar. There should be very little, and it should be very light in color.
Thaw out your clean safrole.
Where's my KOH?
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You can repeat the freeze/thaw process a few more times if you are a stickler. If I do this the crystals are HUGE.
I find that some water may condense in the neck of the bottle, but if you want you can leave the bottle open in the fridge, your automatic defrost fridge will pull the moisture out of the bottle. Not that a little water will be a big problem.
There might be some safrole left in the crap jar, so you could try the freeze/ thaw cycle with that stuff too to see what you get.
Slack