Editor's note: William Breathes became the planet's first professional medical marijuana critic when he joined Westword in 2009, and since then, he's emerged as the local expert on all things cannabis.

Today, he lists his ten favorite marijuana concentrates of 2013.

Check out his choices below, and click on the accompanying links to read his original reviews of the shops that made the cut.

Number 10: Dry-ice-extracted kief -- Pure Pure specializes in ice water-extracted hash, including one blend that looked more like dark amber tree sap than hash. I was assured it was pure plant material extracted with water, then whipped into a taffy-like consistency. But to me, the dry ice hash was the standout. It was fairly priced at $20 a gram for the blended, eucalyptus-smelling red powder and it was the perfect addition to bowls and vape loads for an extra kick. Number 9: Mixed hash -- Artisanal Medicals I was interested in the $12.50-per-gram icewater hash, which I was told was "dab-able" on a skillet or nail. It looked the part and was broken down into shiny, waxy pellets that melted and bubbled on top of a bowl or screen but didn't really hit the dab-able mark. Nevertheless, it was some of the best-produced icewater hash I found all year. Continue to keep counting down the ten best marijuana concentrates of 2013. Number 8: White Grape bubble hash -- People's Choice Wellness On first glance, it looked like dark, oxidized warehouse-quality hash. But cracking the lid open on one of the tiny jars in the shop let out the most wonderful, strain-distinct smell, and instead of being hard, black rocks, the hash crumbled when touched. At home, it melted down like a crayon on top of the bowl when hit with a flame and burned down smoothly, overwhelming the pipe with flavor. This is perfectly done bubble hash with no frills. It's not shaved down with a food micro-planer, it's not crumbled into bits and pieces in a colander; it's just well-made bubble hash. Add to it the $15-a-gram price and I would go back for hash from People's Choice any day of the week. Number 7: Golden Goat Shatter -- Boulder Wellness Center After a lengthy hiatus from butane waxes, I finally found some hash worth bringing home in the Golden Goat shatter oil. Also tempting was the Headband shatter, house blend shatter and Bruce Banner shatter. But the Golden Goat retained most of its natural smell. The rock-hard concentrate warmed up in my fingers and made for manageable dabs that vaporized instantly and cleanly on a nail and melted like amber ice chunks over a bowl. It was extremely potent, too. Pinhead-sized dabs were enough to overwhelm my senses for a few minutes before settling into a strong, energetic high. Continue to keep counting down the ten best marijuana concentrates of 2013. Number 6: OG hash -- Verde The Verde merge with Pink House also means that Verde's hash is being processed by Essential Extracts, which operates out of Pink House facilities. Verde had a sizable collection of about nine different strain-specific hashes, all divided into half-gram jars selling for $15-$20 a shot. At the high end, the 70 micron Golden Romulan and Lavender Haze were appealing, but I opted for the 25 micron "OG" hash. Opening up the little half-gram hash container let out nearly the same strength smell as popping open the ounce jar of Oaksterdam OG on the shelf, and the tiny granules of orange hash were waxy and expertly dried. Melty on top of a bowl and perfect just by itself, this added a delicious extra pain-relieving kick to my bowls. Number 5: Mob Boss hash -- L'eagle Services The owner said staffers dry the icewater-extracted hash for twelve weeks and cure for another month or so before it hits the shelves. I don't know if I fully buy that, but whatever the folks there are doing, they are doing right. This is full-melt, clear-dome icewater hash the way it should be done. The owner also pointed out that it's the same quality as other "solventless" products without the pilled-up chunks achieved through micro-planing or pushing hash through a colander. I thought it resembled a wedge of cheese-like BHO, but without the chemical-heavy wax smell. It burned amazingly in a bowl, forming large bubbles of oil and hash as it cooked down, and also melted well on a hot titanium nail, making it the first dab-able hash I've found at dispensaries in months. Continue to keep counting down the ten best marijuana concentrates of 2013. Number 4: Kandy Kush shatter -- LoDo Wellness Hash selection was slim pickings when I showed up, with only a single $35 gram of Kandy Kush shatter and a lone $30 gram of blended wax on hand. But the single gram of golden, frozen oil, produced by Top Shelf Extracts from trim out of the LoDo Wellness garden, was some of the best I've seen from that company, and I instantly snatched it up. Very clear, very clean and very tasty, the oil burned with a kushy, earthy flavor on the head of a hot titanium nail. Small, BB-sized dabs were enough to put me right for a couple of hours, though the mouthwatering taste dictated that I always take at least two dabs at a time. Number 3: Jedi Kush nug-run shatter -- Lush Lush has $30 grams of shatter oil made from trim as well as $50 grams of oil made from actual buds. The center also carries waxes, but the only concentrates on the shelf when I visited were grams of the ultra-clear Jedi Kush nug-run oil made in-house by hashmaker Ryan Skipton. The $50-a-gram price is steep (and absolutely the most I would pay for concentrates from a dispensary these days), but it looked like the chunk of amber on top of Richard Attenborough's cane in Jurassic Park (minus the bug). What I brought home was odorless but not entirely flavorless: There was an added skunkiness to the otherwise vaporized-THC flavor. I've had tastier shatter before, so that was the only knock. But otherwise it was a to-the-moon blast of medicine that turned a gurgling, cramping stomach into an American breakfast-slamming appetite in five minutes. Continue to keep counting down the ten best marijuana concentrates of 2013. Number 2: Blended 75 micron bubble hash -- Compassionate Pain Management The blended bubble hash looked phenomenal and smelled like a jar of mixed buds from a hippie's closet, so I snagged a gram for $30. The crumbles of hash looked a lot softer and meltier than they really were -- not so much melting down into the bowl as they burned up. But they had a lot of flavor and added an indica-heavy body buzz. I had to try and stop myself from topping every bowl with it, and ended up not doing a very good job. It was way better than pressed black hash most places sell now as an afterthought, and something that is definitely lacking at dispensaries in the hash-oil-heavy medical market. Number 1: Pre-303 Kobe shatter -- The Health Center University Hills The Health Center contracts BHO and shatter hashes from outside vendors. Stay Concentrated handles the shatter, producing a regular $40 gram of shatter, de-waxed shatter for $5 more, and an insanely expensive $70 gram of shatter made exclusively from buds and not trim. I opted for a gram of the basic shatter made from a mix of Pre-98 Bubba Kush and El Diablo dubbed Pre03 Kobe. The same concentrate won the shop third place in the High Times Cannabis Cup back in April 2013, and it was easy to see why. Despite not being de-waxed, the oil held clarity for days (still clear, actually) and vaporized on a titanium nail with a full-flavored kushiness capable of punching you straight in the cerebellum. At $40 a gram, this is right in the perfect price range. I'd love to try the flower-only shatter, but I can't imagine how it would be $30 more potent and flavor-filled than it already is.

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