In this post I'll cover my observations on performance of the new SSP burrs. I expect to add to this post as I evaluate performance over time. In my experience, opinions formed over a lengthy period of time seem to be more valid than measurements, blind tests and impressions formed during the early stages after an upgrade.
In particular, I'll be updating this post after I break in the SSP burrs with about 10 lbs of stale and cheap beans that I have on hand expressly for that purpose.
In the following tests, %TDS and extraction yield percentage were measured/calculated with a VST Lab III refractometer and CoffeeTools.
As mentioned in the first post, I ran a couple of baseline shots on the Mythos burrs to compare with shots pulled on the SSP burrs. I used Dharma Blend from Temple Coffee Roasters, a light-medium roasted blend that I drink regularly. This particular batch is a bit lighter than usual, probably around 110+ on the Tonino scale. As such, it's a little harder to extract than the typical Dharma Blend I get.
I pulled two shots of the Dharma Blend on the Mythos burrs:
[EDIT: You'll have to widen the window or scroll right to see all the columns (last is %EY)]
The first shot tasted a bit under-extracted, so I boosted the temp to 203F from 200F and pulled a little Lungo. Oddly, that didn't change the %EY and the second shot still tasted a little under-extracted. I took this as a sign that, as a light roast it may not have been fully developed and maybe 18.86% was all I could get out of the bean without resorting to a "Slayer-like" shot (i.e., long, slow preinfusion.) Or maybe that's all the Mythos burrs could get out of these beans.
I also ran two shots with the SSP burrs. Like FotonDrv, I was blown away by how much quieter the grinder is (completely different sound) and how fluffy the grounds are. But I also noticed that very large chunks came out of the grinder at times, and the ejection of grounds seemed to come in waves or pulses, almost like the grinder was spitting out blobs of grounds. When I used the open-palm method to purge the last of the grinds, quite a bit came out and it took several pats to get it all. While this bears watching as the grinder breaks in, it didn't seem to affect the shot quality at all (see below.)
I forgot to time the grind, but like FotonDrv I think it's at least as long as the Mythos burrs (29s) or maybe longer. Will get a timing tomorrow AM.
In my alignment tests (see previous post) the burrs touched about one number coarser than the Mythos burrs, so I started with a grind setting of 7. The grounds looked so different, so "powdery", that I was concerned I had under-estimated the shift in grind setting and that the shot was going to choke the machine.
But it didn't. The shot ran a little slower than the second Mythos shot, but the grind setting was very close to where I thought it should be. Distribution didn't seem to be a problem, with a reasonably pretty pour from the bottomless PF. Here's the data:
The higher retention jumps out, but I would caution coming to any conclusions on that. My Flat retained more when the Mythos burrs were brand new, too. After break-in with 10 lbs of beans it settled down, eventually reaching 0.1g-0.2g retention after 2-3 of months.I'll l report back if there's any change in retention after I run 10 lbs through the SSP burrs. If they're anything like the Mythos burrs, I expect the retention to improve. I'm also guessing that the grind setting will move about one number finer as well, like the Mythos burrs.
Noting the retention, I opened the burr carrier to inspect what had been retained. There were two clumps of grounds between the sweepers, each about the size of an elongated coffee bean. This suggested that perhaps I'd used a bit too much water for RDT. So I didn't do RDT on the second shot. This time a little less was retained, and when I opened the burr carrier the space between the sweepers was completely clean, but the burrs had considerably more fine material on them. It looked like a fine coating of chaff. I suspect RDT will be the way to go, but maybe with even less water than the Mythos burrs required (which was very little.)
The first shot tasted ashy, so I cut the temp back to 200F. The second shot wasn't ashy. This, and the higher extraction yields, may be a sign that the SSP burrs are producing grounds that extract a little more efficiently.
Note that on the second shot I changed the grind setting to one mark coarser, but the shot ran two seconds longer and had higher %EY (possibly due to the slightly longer shot time.) Seems backwards (i.e., a coarser grind should run faster), but I would also caution about coming to conclusions about this. I recall that before full break-in my Flat was similarly inconsistent.
As for taste, while my impressions are completely subjective, I've been doing quite a bit of cupping over the past few months while I've been learning how to roast. So I'm in the habit of paying a close attention to flavor components, defects, etc. I wouldn't say it was "God Shot vs Sink Shot", but I felt that the SSP shots were brighter, more balanced and had quite a bit more bite on the tip of the tongue, similar to the "pop" I usually get from Slayer-like shots. This could be another indication of more efficient extraction. The shots were definitely not as sour as the shots pulled with the Mythos burrs, which is a good thing. I'm hoping this is for real, but only time will tell.
[Note: I decided to do the initial comparison with espresso only because I didn't feel that I could reproduce pourover cups anywhere near as consistently as I can reproduce espresso shots. I might have been able to do that with my vac pot, but time was too limited for that protocol today.]
EDIT: Performance After 2.5lb Break-in
Yesterday I ground 2.5lb of stale beans leftover from failed roasts. I did it in 60g batches, per a recommendation from Denis when my grinder was new. I have 10lb of beans to use for break-in, but thought it would be interesting to see how the burrs change at the 2.5lb, 5lb, 7.5lb and 10lb marks.
This morning I pulled two shots of Dharma Blend:
(Again, widen the screen or scroll right to see all the columns. %EY is last.)
Several things jump out:
1) The retention has improved to almost nil. Now, the numbers are a little misleading because RDT add 0.1g-0.2g, but that was true of the earlier shots. In any case, it's a definite improvement.
2) The grind setting has moved more than one number in the fine direction (1.4 on the second shot.) That's more than I expected after a relatively small amount of beans for the initial break-in.
3) I didn't record the grind time for the pre-break-in shots, but I'm pretty sure they were close to the Mythos burrs -- on the order of 30s. I did a terrible job with the iPad stopwatch trying to record the grind times on these shots (fumble-fingered it.), but I believe 20s-25s is about right. Definitely faster than before and faster than the Mythos burrs. I'll get better numbers next time.
4) %EY is quite a bit higher than the best I could get from the Mythos burrs (almost 2% for the Lungo shot), and significantly higher than the pre-break-in numbers.
5) As you can see, the shot times are a little shorter for the equivalent brew ratios pulled with the Mythos burrs, so I could have gone a little finer on both shots. Not only does that mean the grind setting has moved even finer than shown, the %EY probably would have been even higher had I ground finer to match the shot times.
That 2.5lb really made a difference!
I'll pull some shots of a different coffee tomorrow, for taste not measurement, then I'll grind the next 2.5lb.
EDIT: Performance After 5.0lb Break-in
Here's the data from two shots of Dharma Blend, the first Normale, the second Lungo:
Retention seems to have stabilized at very minimal. The grind setting has moved finer by at least two minor ticks. The Normale shot has slightly lower %EY than last time, but it also ran faster. Probably means the grind setting has moved three ticks (i.e., should have been pulled at 5.4.) The Lungo shot seems to confirm this, running quite a bit faster than after the first 2.5 lbs. Note the %EY has jumped quite a bit on this shot.
EDIT: Performance After 7.5lb Break-in
Once again, here's the data from two shots of Dharma Blend, the first Normale, the second Lungo:
Retention is still excellent. The grind setting for the Normale shot moved finer by two minor ticks, more than I expected, the grind time is a little faster, and the %EY increased about 1.5%, which is quite a bit. Typically %EY measurements are somewhat scattered, so this may be an outlier. Will check again tomorrow. I didn't match the previous shot time for the Lungo shot. Probably went a little too fine. I would have expected the %EY to be even higher than before this break-in round, but it's lower. Again, it could be an outlier. I'll check a Lungo shot again tomorrow.
I should also note that there's less clumping and pulsing now.
Not quite ready to draw final conclusions, but it looks like the biggest change occurs after the first 2.5 lbs, but there's still movement in the grind setting, grind time and %EY through 7.5 lbs.
Will report back after the last 2.5 lb break-in session.