I have been having challenges dialing in a decaf dark roast espresso bean. Any suggestions are welcome. The following is from a log I kept over 2 weeks, if you cannot sleep and welcome some tedious reading:
15 Gram IMS Basket on Lelit Elizabeth with With IMS Precision Screen (and with a larger grind dial modification, for more precise grind setting). Note: clockwise (from 0 towards 9.9 or less) is finer; counter clockwise (towards 0.1 or higher) is coarser.
· Shot 1 - 13.5g in, 20.0g out, 11 second bloom pre-infusion, using a “9.25” grind setting on a Eureka Mignon. Ran 48 seconds, including the pre-inf. 8.5 bar pressure. Acidic taste, thinner (not fuller body/mouthfeel). Temp 95C. “Burnt” taste.
· Shot 2 - As above, 9.5 dial setting (2.5 tick marks coarser). Abit more balanced, but still burnt taste.
· Shot 3 - As above, 9.5 dial setting, no pre-inf. Decent balance (of acidic vs sourness), but still thin body. And ran surprisingly slow (45 seconds).
· Shot 4 - 13.5 in, 20 out, 6 second bloom pre-inf. Decent strength, but abit sour. So assumed that it is under extracted.
· Shot 5 - As above, but at 9.6 grind and 8 second bloom pre-inf. Ran 42 seconds.
· Shot 6 - As above, which ran 41 seconds.
· Both Shots 5 and 6 had sour notes (just a tad, but they were there). Tasted abit better in cappuccino, but I have made better tasting drinks than this!
· Shot 7 - 13.5 - 26.0 (by accident) - more balanced, better extraction (more interesting flavours, but thinner body)
· Shot 8 - 13.5 - 25 in 45 seconds, with 8 second bloom pre-inf. 9.6 grind. OK balance between sour and bitter, but I do wish I could get more sweetness. And no complexity.
· Shot 9 - 13.5 - 26.0 with 9.8 grind. 8 second bloom pre-inf. Faster flow than shot 8. Balanced, maybe a tad acidic. No complexity in the shot, but detecting some in the cappuccino. So extraction is likely up, due to longer shot.
· Shot 10 - 13.5 in 39 seconds with 0.0 grind (a tad courser). Thought it would flow faster than this. Now getting burnt, ashy, burn’t bitters, likely due to higher extraction of these dark beans.
· Shot 11 - 15.0 - 29 in 41 seconds, incl 8 sec bloom pre-inf. at an even course 0.5 grind. Balanced shot with a somewhat thicker mouth feel (than the prior shots). No burnt or ashy tastes, but no other complexities. Flow looked a little uneven and the top of the puck had some holes. Taste in cappuccino - more body, less extracted complexity. Perhaps there was not sufficient headroom in this shot.
· Shot 12 - 14.0 - 27.5 with 0.0 grind in 32 seconds, including 8 second bloom pre-inf. A tad sour.
· Shot 13 - 14.0 - 27.0 in 38 seconds at same (0.0) grind, including pre-inf.
· Both shots 12 and 13 were a tad thinner with less body. Better taste in cappuccino than the Shot 11 with 15.0 in- 29 out (i.e. more extracted flavour) but less body. I’d like more body.
· Best shot of the 13 shots was Shot 9 (13.5 - 26.0 at 9.8 grind with 8 second pre-inf).
15g IMS Basket with Lelit Screen
· Shot 14 - 13.5 - 26.0 in 30 seconds with 8 second pre-inf, at 0.2 grind.
· Shot 15 - Same as above
· Both shots had weak strength, not much body and not much complexity. But not sour or bitter.
· Shot 16 - 13.5 - 25.0 at 0.0 grind in 40 seconds (incl. 8 second bloom). Still weak strength and insufficient complexity.
· Shot 19 - 13.5 - 26.0 in about 45 seconds. Still weak strength, but some flavour complexities are emerging.
· Shot 20 - 14.5 - 26.0 in 36 seconds with 8 sec bloom pre-inf. Abit more body, but less flavour extraction. Still, a semi-decent shot.
· Shot 21 - 14.0 - 27.0 in 37 seconds. Abit less body (than Shot 20) but a tad more flavour (i.e. complexity). (When I say flavour I mean complexity).
· Best shot of this series is Shot 21.
· Best shot of this and the prior series is Shot 9. But still a 7 out of 10 (10 being best), on my taste scale. I’ve never poured better than an 8 (I am hard on myself, when I score).
A Completely Different Approach (Shorter Shots at 1 to 1.5 ratio, with a coarser grind). Using the 15g IMS basket and the Lelit Screen. Varying temps (see below).
· Shot 22 - 14.0g in, 22 out in unknown time. Grind setting at 0.5. Temp at 93c. The shot was abit sour. However the taste in cappuccino had good strength, good length and even a a touch of complexity. If I could get this taste, but eliminate the slight sour note that would be great! As per the next shot notes, I could not repeat this shot, let alone eliminate the slight sour note.
· Shot 23 - 14.0 - 21.0 at 94 C (up from 93C). Ground a tad finer at 0.3. Was hoping to get more extraction and eliminate the sour note. Shot taste declined from Shot 22. Less body, less complexity, less length and a tad acidic. So I thought that I went to far along the extraction scale and backed off on the next shot.
· Shot 24 - 14,0 - 21.0 in 35 seconds with 8 second bloom pre-inf 0.3 grind; 93 C temp. Sour shot!
· Shot 25 - 14.0 - 22.0 at 0.5 grind at 94 C. Did not note the time. Even more sour than Shot 24.
· Shot 26 - 14.0 - 21.0 at 9.8 grind. Still the same sourness! *** *!@#
· Best shot of this series (and best of all three series) was Shot 22. I liked the mouthfeel and the body and the complexity, but it had just a tad of sourness. Moreover, I was unable to repeat it.
· Note: I am more often that not seeing some puck fracture, and the occasional puck hole. Is my puck too thin with this basket, for a dark roast?
The Next Series (Just Started) - Back to an 18.0 IMS basket and the same Lelit Screen
o Shot 27 - 17.0g in, 25.5 out with 0.4 grind. At 93.0C. Way too slow.
o Shot 28 - Attempted 17.0 in, 25.5 out at 93C, with 0.8 grind (coarser), but the scale battery died and it ran too long.
o Shot 29 - 17.0 - 26.2 or so (using an older, less responsive scale). Still too sour and too thin.
o Gave up and will try again tomorrow.
Any Trendlines From The Above?
I am unable to find a trend line in the above, that would point me in the right direction. It could be that a dark roast bean (that is frozen and ground from frozen) needs a thicker puck, or it might fracture. I am not sure if I am right or wrong about that. Also, not sure whether it is a good idea (or not) to grind dark roasts from frozen? Am I creating too many fines?
I also noticed that my water flow (from the grouphead) is 180 ml in 30 seconds, whereas I read that it should be 200 to 280 ml (say 240 midpoint). Increasing the BAR pressure would increase the flow. If this is a linear relationship, then I would increase the BAR to 11, by adjusting the OPV valve. Is this part of the problem? But I worry that 11 Bar would be too high; I do not wish to damage Elizabeth.
Next steps: I vaguely remember reading somewhere that too low pressure can create shot inconsistency. Additionally, a somewhat higher pressure will allow greater water flow, and will also extract more. So I might try increasing the BAR pressure to say 10. Any other broad ideas? It would be great to enjoy a great espresso shot or cappuccino, more than once or twice in 30 shots !!
And … my apologies for the long long post.
With some frustration!!! JHCCoffee.