Despite advice to the contrary, I've often chosen the freshest beans available and started using it immediately. (At least for practical reasons - if I just bought it, it's probably because I ran out.) But the stuff I just bought yesterday 12/2 was ROASTED 12/2. And I'm getting issues like random sprays and flow accelerating more rapidly, that I rarely get on my equipment. Is excess CO2/degassing the likely culprit for those two issues? E.g. CO2 bubbles disturbing the puck and creating channeling? If so, then I finally "understand."

Yes.

When pulling very fresh-roasted coffee, let the ground coffee sit for five-ten minutes to off-gas the CO2 and then pull the shot.

That makes sense, I will try that. Thanks for the tip.

Very useful tip!

For more traditional blends, could too fresh beans possibly result in unusually sour shots as well?

barNone wrote:Very useful tip!

For more traditional blends, could too fresh beans possibly result in unusually sour shots as well?

To be honest, what I would normally do is to brew the coffee with another method for a couple days. However, sometimes circumstances warrant.

Sour shots are said to be a result of under-extraction - but that seems to mean full extraction of the sour bits of coffee, and under-extraction of the bits of coffee that modulate the sourness. So CO2 outgassing during the pull could interfere with some part of extraction.

Myself, I have this quote printed and posted behind my grinders in very large type:

another_jim wrote:Acids and bitters extract first, caramels and buffers/mouthfeel components extract last. If an espresso is too in your face; grind finer, dose lower and extract more. If an espresso is too blah, grind coarser, dose higher, and extract less.

If you use this standard for better espresso shots; then very light roasted coffees, which have fewer caramels and buffers, need a finer grind and higher extractions, whereas a darker coffee, with more caramels and buffers, needs a coarser grind and less extraction.

Despite all the tech-babble, that is all there is to it.

From: Why is espresso with higher extraction yield "better"?

The guy from april coffee who placed second in 2019 brewers cup and had the highest coffee score in the competition roasted his coffee the same day. He ground his coffee and let it sit for 45 min before brewing. So basically the whole "waiting x amount of days" for off-gassing and developement of flavors has been turned on its head lol.

I'd say that is a hasty generalization. Patrik Rolf has explained why he did it, and that he literally tailored everything from roasting to brewing. He also wasn't brewing espresso with a prosumer pump machine with no pressure/flow profiling.

Regardless, try it yourself and see. I've roasted coffee that I have brewed (not pulled) right out of the cooling tray; I've roasted the same coffee differently and that roast didn't come into its own until two-three weeks after roasting. YMMV.

In my experience resting properly is crucial. I'm sometimes tempted to open a new bag of beans early but in my experience not worth it. I'm at minimum 7 days exposing it to air on day six but my standard is opening the bag at day 10. I brew scandinavian SO with a EK43 so it might be different from darker blends.

I came home from vacation opening a three week old unopened bag and got high tasty extractions so I'm not scared of resting properly.

Resting is great, but when you don't have the luxury, grinding and waiting can help.

I remember at the soft-launch of Handsome Coffee Roasters that one of the owners mentioned that they didn't have time to rest the coffee so they were using this trick.

There's various factors to aging. Grinding dramatically increases surface area, and therefore accelerates aging that depends on air exposure. So it will increase both out-gassing and oxidation. Since oxidation is not good for taste, and starts after the out-gassing completes, letting beans or grind out-gas when not stored in a valve bag creates a a timing problem. You want to do it just long enough for the beans to out-gas, but not to start 'rusting.'

I was told 30 minutes is the rule of thumb for doing espresso on a fresh roast (60 minutes if it's a robusta blend); Craig mentioned 10 to 15. The brewer's cup champion used 45 minutes, but presumably on a coarser grind. I'm guessing this is an area that could use some old fashioned experimenting and look up table making.