Kif comes from the Arabic kayf, meaning pleasure. While hand rubbed charas is ostensibly the oldest method of harvesting Kif, sieving does date back to antiquity and still has the potential to produce high quality tasty and aromatic concentrates in the form of isolated trichome heads, so still has a strong following.
An excellent book on the subject and its history is Hashish, by Robert Connell Clarke, published 1998 and available on Amazon.
The process used to harvest the Kif depends on the end result desired, but they all rely on using sieves sized to allow the trichomes or debris to pass, while retaining most of the plant material. The trichomes harvested can then be consumed as is, or pressed into blocks or bricks.
Different strains have different trichome sizes, so the process has to be custom refined around the material you are working with. Tastes also vary, with some preferring to smoke the Kif as is, and others preferring it pressed.
For equipment, you will need a good microscope to keep track of your progress, as well as sieves. I like this microscope designed for measuring cloth thread counts, because it not only presents a crisp clear picture, but has a grid that allows measuring trichome head sizes:
Measuring Microscope with optic grid
Sieves come in many sizes and designs, plus you can build your own. If you would like to build your own, see the DIY Dry Sieving Frames page.
Bottom view of DIY Sieving fame.
Stack of six self nesting sieve frames with different micron meshes, with lid and bottom for storage and transport.
You can extract a usable product with a single frame, or refine it to higher grade using successive frames. The number and micron size of your sieves depends on the trichome size and the desired end product. Material to be pressed into slabs, typically requires less refinement than that which is to be consumed as “Full Melt.”
You also don't have to get complicated. A simple pollen shaker, filled and stored in the freezer works. You simply take it out and shake it on demand.
Simple Pollen Shaker
Cannabis produces three different types of trichomes, all of which ostensibly produce cannabinoids and other terpenes/terpenoids, but the ones we harvest with dry sieving are the Capitate Stalked trichomes, which consists of a bulbous gland on the end of a stalk.
Bulbous, Capitate Sessile, and targeted Capitate Stalked trichomes.
Capitate stalked trichomes in clear, cloudy and amber.
In heaven the heads break off cleanly where they connect to the bulbous head, leaving behind the stalks as well as the Captate Sessile, but alas here on Planet Earth it is not to be so. What typically happens when we sieve is that we end up with a mix of the Capitate Sessile, along with the Capitate Stalked, some of which broke off at he base of their stalk, as opposed to where it connects to the bulb.
Here is a picture of the first sieve, typically around 150 micron and 140 micron in this case by Bubbleman, who shared the photo on line.
First sieve before refinement showing stalks and crystolith hairs
The first sieve you see, actually produces a tasty and efficient dose, but for those who seek the ultimate Kif experience, it can be further processed through successive sieves, until it reaches full melt state. It's sort of like consummate tea drinkers can taste the tea bag, in that after experiencing pristine museum quality full melt kif, you can taste the cellulose when there are stalks in the mix.
Trichomes heads refined to Full Melt.
The difference between the last two pictures, is about 35 to 40 minutes of refining with successive mesh screens. Robert Clarke, offered the following mesh size suggestions for refinement in his book, HASHISH.
150 microns - large plant debris
130 microns - very large resin glands
110 microns - large resin glands
90 microns - medium resin glands
70 microns - small resin glands and debris
50 microns - very small debris and little resin
below that - very small dust and debris
Bubbleman at http://fullmeltbubble.com/forum/forum.php offers a sieve kit with three screen starting at 140 micron, with 107 micron as the middle screen and a final 70 micron screen. Available in a purdy burly maple box for those so inclined. Also a good place to pick up dry and wet extraction techniques.
They also supply larger 26 X 12 nesting aluminum framed sifting frames, for processing larger batches : http://www.freshheadies.com/store/SKM4.html
Available at xxx in 36" X 25" from Bubble Bags: https://www.bubblebag.com/dry-sift.php
Dry sieve, means just that. Wet sticky material fouls the sieves, so we typically cure our material 90 days or longer before sieving. We typically strip the fan leaves and hang the plant for the first 5 to 7 says, or until the small stems snap, and then clip off the buds and jar them, burping daily for the remaining cure time.
The material is ready for dry sieving, when the trichomes are solidified enough to not rupture and foul the screen with resin. The first sieve separates the raw working stock from the plant material, and the second the heads from the stalks and hairs, and the third the prime heads from the fractured ones and small debris.
When its time has come, we start out by breaking up the buds over the 150 mesh stainless steel screen, which is nested atop the 110 screen, which is on top the 70 micron screen, which rests on a collection surface.
We gently move it around on the stainless screen with our hands or a stiff card, so that the trichomes break off and fall through the mesh. You can keep track of where you are at by continually reviewing the material with a microscope to see what is left.
As a general rule, the longer you work the material, the more foreign plant material you pick up in the kif, so if you are going for bragging rights, you would cease sieving when you begin to pick up excessive plant material, and finish of the material in a separate batch or with a solvent.
Running for the max, we stop sifting when a microscopic examination shows most of the trichomes are gone, and we can still press the trichomes extracted between a finger and thumb for thirty seconds or so, and it sticks together into a lump.
Once the primary sieve of the raw plant material is complete, that frame is set aside and the other two sieves are used to refine the extract by removing the stalks, crystolyth hairs and plant debris from the intact trichome heads. We do that by gently carding the kif deposited on the 150 micron screen to break up conglomerations and remove debris.
After we've worked the kif deposited on the 110 screen, we set it aside and continue the gentle carding back and forth across the screen, further refining it. We work the 110 screen for around 10 to 15 minutes, judging by sight when to stop and move to the 70 micron screen. If nothing else, refining kif is an exercise in patience. Be gentle with the kif and let what will fall through the screen, rather than being forced or heads broken up.
The 70 micron screen catches most of the hairs, so a much longer working time is required to card them through the screen. Working in small batches, you might achieve 90% glandular heads only in 30 minutes or so, and to remove the remaining 10% might take another 30 minutes.
How clean you get it is a matter of both taste and personal pride and aspirations. 90% clean is tasty and mostly full melt.
There are also other ways to remove the debris than carding, such as electrostatic separation.
There are also other methods of dry sieving. Another one for instance is to break up cured the material by hand and put it in a fruit jar about 2/3rd full. You then put the lid on and stick in the freezer overnight. Next day you remove the lid and stretch a suitable 150 micron fabric over the opening and secure it with the ring, before shaking it vigorously over a large sheet of paper. Sort of like peppering your eggs using a salt shaker with holes too small.
Stop shaking when yield drops off and before green color starts to appear.
I've seen the same thing done with a Tupper Wear tub, with the center of the lid cut out to make it more like a donut.
Going the other way, there are precision sifters made for soil through pharmaceutical samples that nest and work by hand or with a mechanical shaker.
Available in following sizes:
A key point to consider, is that the above is the hole size when clean but it diminishes as the sieve gets dirty, so cleaning after each use is important. In most cases, as long as you have been dry sieving, a simple brushing with a painters paint brush will suffice.
If they do get gooed up, a paint brush in conjunction with Isopropyl alcohol usually works.
Here is a link to Cleveland Vibrator and Chitra Engineers for Pharma grade vibratory and ultrasonic sieving equipment:
Thermal cycling radically different cross sections, like a bulb on the top of a skinny stalk, introduces thermal stresses from uneven expansion. One technique is to bag the material and exclude the air, before freezing, followed by thawing, followed by repeating a dozen cycles to make the trichome heads more prone to fall off the shafts.
Yet another subject surrounding dry sieving and that is what do you do with the Kif after separating it? Some brothers and sisters swear that good hash has to be pressed and aged to reach its ultimate glory, and yet others believe pressing subdues the flavor.
Sadly this tattered old Gray Wolf hasn't done sufficient research in the Middle East where the premium Hash originates to have an opinion on the best of the best, nor do I see opportunity for research opening up in the foreseeable future. Less shooting, bombing, and beheadings when I visited about 15 years ago.
What I do know is that I like them both and my unrefined boetian tastes likes loose dry sieve best.
I also like the idea of growing and sieving my own, so as to know what adulterations, if any, are present and that I'm not financing a terrorist organization creating disharmony in the universe.
The best way for you to tell for your very own self, is give them both a try.
That does bring up the issue of what you do with larger batches of kif, until they are consumed??
Heat, UV light, moisture, and oxygen are kifs bete noire, so the best way we've found to store loose kif is in a sealed container, preferably vacuumed or nitrogen purged to exclude oxygen, and stored in a dark freezer. Besides slowing degradation, it also preserves more of the monoterpenes.
Full melt kif is hard to keep on a pipe screen, so super fine stainless screens are typically stacked to hold the resin long enough to vaporize waving a flame over it.
Here is a link to vacuum sieving, another method of refinement: https://www.youtube.com/watch?v=2cvYvfqYVZE
Here are some links to sites dedicated to dry sieve, with discussion by recognized experts. Like all international forums, there are many characters and opinions, so you must pick what is useful and leave what is not:
How to make full melt: https://www.icmag.com/ic/showthread.php?t=253284
Some light reading:
Isolation of Secretory Cells from Plant Glandular Trichomes and Their Use in Biosynthetic Studies of Monoterpenes and Other Gland Products, by Jonathan Gershenzon, David McCaskill, Jean I. M. Rajaonarivony, Charles Mihaliak, Frank Karp, and Rodney Croteau’
Isolation and Purification of Glandular Secretory Cells From Artemisia Tridentata by Percoll Density Gradient Centrifugation, by J. Henrysl Onaen, Dr Ick G. Kelse
Secreting Glandular Trichomes: More than Just Hairs, by George J. Wagner
New Approaches for Studying and Exploiting an Old Protuberance, the Plant Trichome, by G.J. Wagoner, E Wang, and R.W. Shepherd
Morphology and monoterpene biosynthetic capabilities of secretory cell clusters isolated from glandular trichomes of peppermint (Mentha piperita L.), by David McCaskill, Jonathan Gershenzon, and Rodney Croteau
Developmental Regulation of Monoterpene Biosynthesis in the Glandular Trichomes of Peppermint, by Marie E. McConkey, Jonathan Gershenzon, and Rodney B. Croteau