Troubleshooting random bad shots

#1: Post by **Simon345** » July 20th, 2017, 11:25 pm

Have been making espresso for long enough that i feel like I have a solid workflow, but am frustrated at the occasional bad mystery shots that taste bitter, ashy, lack overall flavour.

Pulled one of these shots today and just cant work it out. Mythos One, LMLM set to 92c, shot poured in one syrupy stream and gave 32g in 28s from 18g in an 18g vst. Crema was dark, and shot looked great. Exact recipe exact beans on another shot will taste fine. What are possible causes of these occasional bad shots?

#2: Post by **caffeinezombie** » July 21st, 2017, 7:35 am

What is your workflow with the Mythos One like? I find that the amount of beans in the hopper makes a difference in the shots.

#3: Post by **emradguy** » July 21st, 2017, 5:56 pm

Could be a number of things going on. As suggested already, weight of beans in the grinder hopper can affect grind output. If your machine has been sitting idle too long it may need a cooling flush, lest you over-extract. If you're using a spouted pf, it could be you've got occasional chaneling you haven't noticed...or perhaps an off-balance extraction, suggesting you need to go back to basics on distribution technique.

#4: Post by **jaystray** » July 23rd, 2017, 12:31 pm

When was the last time you backflushed it? Also you could try to coursen your grind up and pull a little more out, that could possibly balance the shot out.

#5: Post by **Charlene** » July 23rd, 2017, 2:18 pm

I would switch to different beans to rule a bean problem in or out.

Also, blends are not always homogeneous and it is possible to get a bad shot after it is dialed in.

#6: Post by **another_jim** » July 23rd, 2017, 4:19 pm

Simon345 wrote:What are possible causes of these occasional bad shots?

Randomness.

Any procedure in the real world has variations. Unless you can stably correlate changes in procedures with changes in the taste or its variability; there is nothing more to say.

You imply that your procedures are sound enough that you can generally pull five good shots in a row, and that you have an occasional blip. If that implication is true, that is all there is to say about it. Ove time, you may come up with more stable procedures and gear; but there is nothing you can do right now

If on the other hand, you are BSing, and can't pull two shots in a row that taste the same; you also have your answer. Stop pretending and go practice.

#7: Post by **SJM** » July 23rd, 2017, 5:22 pm

Basically what Jim said.
If it is really 'random' then there is no way for you to 'suss' it out.
Random by definition isn't sussable.