Help!

I'm a fairly seasoned home barista. Been at this for 4+ years, and have experimented with various machinery and diverse coffees.

For the last couple of months, I've been having major difficulties getting a good espresso extraction. Dead spots and channeling in full display through the bottomless portafilter.

With the pandemic, I couldn't order coffee from my favorite US roasters, as they don't deliver to Canada (or at least I can't order without paying a multiple of the coffee price in shipping fees). My faves pre-Pandemic were Caffe Lusso GMC and Lionshare, Red Bird Espresso and the occasional George Howell blend or SO for variety.

I found a few local blends that I enjoy. One is a medium roast mix of Brasilian and Colombian Arabica that is a tad more modern and acidic than my usual comfort blends. I was still able to extract it well by underdosing (16g in an 18g VST) and grinding much finer than with my usual blends.

The second local coffee I have been using successfully is a more traditional all Arabica espresso blend, a bit darker and more chocolatey. For this one 17g doses ground a bit coarser in the same 18g basket yielded perfect extractions.

Yet, for the last few weeks, the same general prep with the same coffees and the same equipment is yielding terrible extractions. And I can't figure out why!

I use:

- Rocket Evo (rotary pump) E61 machine.
- Monolith MC3 conical grinder
- 18 g VST basket
- Monolith 58mm leveler and 58.5mm tamper
- always fresh coffee (5 to 15 days old max)

I'm careful with prep. The Monolith had greatly simplified getting an even grind and distribution. I still palm taps and use a leveler to ensure an even tamp. Importantly, I have not changed my methods.

I've tried tweaks to dose and grind and yet, everything I brew these days comes channels or no longer extracts well, or at least not as previously. I've sort of given up on lighter roasted coffees, as these never extracted really well with my machinery, but now even the more forgiving (less dense, darker roasted) blends extract like schnotz.

Would the experts have any idea what could be throwing my extractions off? I've heard of VSTs having a service life to them, so could that be it? Would that explain these symptoms?

Anything else I'm not considering?

Don't blame the basket, I don't believe there's a single person on this earth who could fatigue a VST basket in home use no matter how much they claim their prodigious usage.

Does your extractions look erratic, gassy and light or mix-colored during the extraction?

You have perfectly adequate (or better) equipment, and from what I read, more than adequate skill. So it's not the equipment side of the portafilter, or the fleshy side of the portafilter.

You don't seem to be chasing ultra-light, low bodied, high clarity espresso shots, so why not let those blends you have on hand rest a tiny bit longer?

Switch out to a less finicky basket. Not all coffees need a VST basket. You'll likely get a lot more flexibility and improved shots out of a simpler basket design like a HQ14 basket.

Let the coffee rest for 14 days and use a HQ14 or stock Faema style basket and try again. If your prep is consistent, you'll get a great shot out of a coffee blend that is roasted well and comprised of good quality coffees.

Please report back!

My beans are too old to be gassy. Not too old as in "no longer good", but definitely no longer "too fresh".

Could it be that both just happen to be suboptimal batches of the two blends?

I agree with you that with this equipment, I should not find myself in this situation. And I hadn't until recently.

It boggles the mind.

I'd best describe it as unequal extractions. No sprinklers in the naked portafilter, but clear dead spots, or areas of limited or no flow, while other areas still flow too much.

If I grind coarser in the hope of a more even extraction, the flow is just way too fast and the coffee has no body.

Finer just gets more uneven.

May try to revert back to an exact 18g in the 18g basket and a somewhat coarser grind, but why would the receipes that used to work perfectly (slight underdosing with a fine grind) simply no longer work for the same coffees? Reverting back to higher doses will mean technically lower extractions, which should yield different flavors than previously.

To eliminate distribution as a cause, consider using the WDT tool included with the Monolith. I know tapping on grinder forks or the palm tap is a generally accepted as a good method to distribute, but WDT is bulletproof in my experience. I had decent success with palm tapping in the past, but have religiously done WDT recently instead and its been consistent in shot times/pull quality. Last shot I pulled with no WDT, only palm taps, and a nice visual inspection to ensure level grounds, the shot ended up being a gusher with lots of channeling. Barring that it could be be a bad batch of coffee. Also being exceedingly rare would be the burrs have somehow ended up being misaligned or non coffee bean object might have unknowingly passed through damaging the burrs. Could open up and examine the burrs to see.

HRC-E.B. wrote:Help!

I'm a fairly seasoned home barista. Been at this for 4+ years, and have experimented with various machinery and diverse coffees.

For the last couple of months, I've been having major difficulties getting a good espresso extraction. Dead spots and channeling in full display through the bottomless portafilter.

With the pandemic, I couldn't order coffee from my favorite US roasters, as they don't deliver to Canada (or at least I can't order without paying a multiple of the coffee price in shipping fees). My faves pre-Pandemic were Caffe Lusso GMC and Lionshare, Red Bird Espresso and the occasional George Howell blend or SO for variety.

I found a few local blends that I enjoy. One is a medium roast mix of Brasilian and Colombian Arabica that is a tad more modern and acidic than my usual comfort blends. I was still able to extract it well by underdosing (16g in an 18g VST) and grinding much finer than with my usual blends.

The second local coffee I have been using successfully is a more traditional all Arabica espresso blend, a bit darker and more chocolatey. For this one 17g doses ground a bit coarser in the same 18g basket yielded perfect extractions.

Yet, for the last few weeks, the same general prep with the same coffees and the same equipment is yielding terrible extractions. And I can't figure out why!

I use:

- Rocket Evo (rotary pump) E61 machine.
- Monolith MC3 conical grinder
- 18 g VST basket
- Monolith 58mm leveler and 58.5mm tamper
- always fresh coffee (5 to 15 days old max)

I'm careful with prep. The Monolith had greatly simplified getting an even grind and distribution. I still palm taps and use a leveler to ensure an even tamp. Importantly, I have not changed my methods.

I've tried tweaks to dose and grind and yet, everything I brew these days comes channels or no longer extracts well, or at least not as previously. I've sort of given up on lighter roasted coffees, as these never extracted really well with my machinery, but now even the more forgiving (less dense, darker roasted) blends extract like schnotz.

Would the experts have any idea what could be throwing my extractions off? I've heard of VSTs having a service life to them, so could that be it? Would that explain these symptoms?

Anything else I'm not considering?

perhaps dumb question. Have you backflushed and soaked your basket? The next thing i would ask is how do you store your beans?