Little pseudo-scientific experiments with the Ascent
I found some free time to assemble my little research notes. I was experimenting with load sizes trying to find if there is some "sweet spot" and to check if the Ascent is really inefficient with small loads or not. I was also trying to understand why some sessions were plentiful and felt like being in cruise mode, while some were really disappointing and left the girlfriend and me wondering what went wrong or if the thing was not just plainly broken!
As I said previously, I'm now convinced most problems people have with vapor production and efficiency with the Ascent come down to an incorrect technic (aka user error) for the most part, and to a low (and variable) vapor/air ratio due to the leaky air-path. The ratio can be corrected more or less easily, but for the technic there are two schools: the flowers adepts and the puck adepts (sans-flowers).
The glass flowers technic is pretty efficient and allows to use micro loads (that ~0.025g figure is impressive
@nigel!) but there are some drawbacks as well... I'm not sold yet, what will follow will thus concern mostly the puck technic.
Test #1: light vs tight packing
Usually with convection you need a loose packing, and with conduction a tight packing. While DaVinci advertize the Ascent as hybrid (which it is) I think most of us agree conduction is the principal energy source in this device.
The first test is easy: take approx 0.12g of material, divide in two equal parts. Select any temperature and do the first session with a tight pack to make a flat puck covering the entire surface of the bowl bottom. Note vapor density. When done, unload and reload with the second half, this time pack very gently, using same temperature. Again note vapor density.
Needless to say in my case, the second test even if the device was already hot yielded a super wispy vapor. After a few hits I opened the bowl and packed the load hard, and got instantly thicker vapor.
Test #2: variable vapor/air ratio
This one is perhaps less obvious and was not much of a problem with my previous glass straws pair which had a good match, but with the other one it's pretty clear. Basically, it could explain a small percentage of the sessions that feel wispy even if the load is packed right (but not the majority, see #3 and #4 which are more likely to be a problem)
Whenever you pull the drawing straw out, the gap between the silicone buddy rim and the plastic air tunnel can vary a little. This will slightly alter the vapor/air ratio by mixing a variable amount of air from the upper part of the device. To test it, select your straws having the worst match and pick the largest drawing straw so that it sticks to the silicone more. Load a bowl, then extend your drawing straw out to the max, trying to pop the buddy rim out a bit in the process, take a hit, note vapor density. Then put the straw back halfway and using the stir tool or your fingers, push back on the silicone buddy rim so it fits firmly against the air tunnel. Take another hit and note vapor density.
This one is easy to fix, no need to discuss it further.
Test #3: mid to end of session puck unpacking
This one is very frustrating. Your session is going fine, and say midway through it, you up the temperature one notch and get only a few hits that become wispy pretty fast. You know there should be more as you just started a new temperature level, but nope, it seems to stop.
I found that some herbs, and more precisely some calyxes forms (those that are tiny and pointy for instance) tend to stay "whole" when grinded, instead of tearing apart, so you end up with a pile of little cones and plant bits rather than a coarse or fine powder. Stickiness can have an impact too. But I clearly have strains that are more prone to this issue and for one it's systematic.
So what happens is that midway through the session, the herb dries and become lighter and the puck becomes all fluffy. The air doesn't encounter enough resistance and the vapor becomes super wispy. Again it's straight forward to test: when it happens, open the bowl and repack hard. In most cases the density will improve at once.
You can also test this one another way: get your bowl going strong, then open it and with the stir tool make it all loose, close and draw. Yes this is a variant of #1 but it happens gradually...
Test #4: see-thru holes
This one is the most frustrating! When it happened and I didn't know the cause, I really thought the device was super uneven. Left me really disappointed with sessions that didn't last as long as they should have. I know there were more hits to get, but the device refused to extract them somehow...
The smaller the load the most likely this problem happens. Also like #3 it can happen gradually during the session. Sometimes it even slowly creeps in... The culprit: anytime one of the 4 bowl holes is not fully covered with a layer of material. Even a pinhead direct see-thu hole and the vapor/air ratio is ruined and extraction stops! Sometimes the puck seems to be packed right, it's in place and packing it further doesn't improve the situation, yet you know there are hits left in there... Find a light source and try to see through from above the bowl. If you see the slightest light spot shining through the puck, it's compromised, and you'll have to stir and repack.
Again easy to test: get your bowl going strong, open it and with the stir tool uncover one of the holes (or using a needle going through the bottom grill) Close and draw.
Test #5: load size vs efficiency
Now I wanted to find if the number of hits vs load size was linear or not. Put simply, I wanted to know if there was a sweet spot for the load size to maximize efficiency. Obviously due to #4 and to some extent #3, there is a limit to the minimum efficient load size as we will see below. I couldn't get as low as
@nigel's figure in a satisfying way in fact. That being said we are talking about micro loads here, about 1/4 of what I would put in a small (tobacco laced) joint! On the other end of the spectrum I didn't test very large loads because they just last forever and are impractical to test. Please keep in mind I did these tests prior to fixing my upper seal leak (yet it was using the best matched straws, so problem was minimal then)
I used a particular strain that vapes really good (selected the one I had that always produced the densest clouds) and which had a very uniform bud quality, to minimize variations due to the material itself. I used a cheap digital scale but it was not super precise, so I also noted the equivalent in number of joints I could roll with the same amount (years of habits make one good at eyeballing the quantity!)
I tried to draw always the same way: 3 seconds depression, then large air intake, holding a bit then exhaling through the nostrils. I counted a "hit" only if it felt satisfying and if I could see visible vapor exhale under normal lighting conditions (again always the same to minimize variation) As soon as a hit was wispy, I didn't insist and raised to the next temperature level. Tests were done in a short period so external temperature variation was also minimal. I used 5 temp levels each time: 177, 185, 195, 205, 221°C taking note of the number of hits per level.
I don't know if people are really interested in the detailed results, and this post is already long enough, but I got surprisingly linear results in the 0.05g to 0.25g range with on average (yes it's a bold claim seeing I don't have that many data points) 34 hits for a 0.06g load and over 140 for a 0.25g load. Below 0.05g and mostly due to #3 and #4 I saw a strong decline with 12 hits on average for a 0.03g load (and overall those sessions felt wispy)
Newer vaped before, so I hope the vapor can satisfy my, after I only combusted my flowers till now...