ewindisch Senior Member Joined: 22 Mar 2012 Posts: 14 Location: PA Expertise: I live coffee
Posted Thu Apr 5, 2012, 7:30am Subject: Home roast - hitting group head screen
I've been roasting for a couple months now and have just started with espresso. I've finally dialed in my PID'ed Gaggia Classic and Preciso grinder to where I'm making 25 second shots that taste really good. Not sour, not bitter, and clean. I'm honestly not expecting that with this equipment, I'll get it any better.
Unfortunately, no matter what I do, my fresh roast (12 hours) is hitting the group head screen. I'm suspecting it is due to the CO2 still in the beans, and I might just have to wait longer after roasting if I don't want a messy cleanup.
Is it the CO2, or do I still have to adjust my grind? Should I even care, enjoy that I'm getting great tasting espresso, and just deal with the cleanup? Maybe I'm otherwise doing it wrong and this espresso isn't as good as I think it is? ;-)
Posted Thu Apr 5, 2012, 7:50am Subject: Re: Home roast - hitting group head screen
Three days is the minimum for me and five days is when the roast really starts to hit peak flavors for me. If my roasts are tasting really good after 12 hours they are over roasted and will start tasting burnt by day 3. But this is all a matter of taste and if you are enjoying it ... who am I to tell you to change.
I'm not following what you mean "hitting group head screen" and "messy cleanup"? Are you saying when you unlock the PF that espresso bursts out all over everything? Or simply that there are wet coffee grinds on your shower screen? Or does the entire puck stick to your screen instead of coming out with the PF?
Normally the coffee should be dosed into the filter basket so that after tamping the top of the coffee puck is just shy of hitting the screen (some say place a dime or a nickle on top of the coffee and lock the PF in place - then unlock and see if there is an indent where the screen pressed the coin into the coffee).
Then when you start the shot and puck gets saturated, it will swell up and should contact the shower screen. So after a shot and knocking out the puck, I usually have some grinds on the shower screen (I use a toothbrush to clean the screen - or they make special brushes just for this - and I rinse the screen clean and use a blind basket to backflush)
My sense of taste finds that 12 hour post roast espresso has a lot of "brightness" almost like a little grapefruit peel. It isn't "bad" - it just has a lot of tea-like flavors and less body.
ewindisch Senior Member Joined: 22 Mar 2012 Posts: 14 Location: PA Expertise: I live coffee
Posted Thu Apr 5, 2012, 8:05am Subject: Re: Home roast - hitting group head screen
AndyPanda Said:
Then when you start the shot and puck gets saturated, it will swell up and should contact the shower screen. So after a shot and knocking out the puck, I usually have some grinds on the shower screen (I use a toothbrush to clean the screen - or they make special brushes just for this - and I rinse the screen clean and use a blind basket to backflush)
Thanks! That makes sense, I didn't realize it *should* it the screen. However, the entire puck is sticking when I remove the portafilter. That does not seem to be right?
I'm quite sure that I'm not overfilling it, as I haven't had this problem with pre-roasted, pre-ground beans of the same measured volume. However, those beans were ground at a different setting. Some of the too-fast or too-slow shots from my roast were anywhere between a few grounds to half a puck... even if I under-filled the portafilter to and tamped hard.
Maybe I just need to grind coarser or finer and adjust the tamp pressure until I get the same quality of pull, without hitting the screen? I suppose one question is, again, should I care? If the pull is good, is there harm in that the puck sticks to the screen? Or if the puck sticks to the screen, is that not a good pull? I'm starting to get the impression that a sticky puck might not be a bad thing? I'm new to espresso :-/
Reading the other related thread, I'm thinking that maybe I'm actually under-filling the portafilter, causing it to be too soupy and not drying out correctly?
AndyPanda Said:
My sense of taste finds that 12 hour post roast espresso has a lot of "brightness" almost like a little grapefruit peel. It isn't "bad" - it just has a lot of tea-like flavors and less body.
Posted Thu Apr 5, 2012, 9:00am Subject: Re: Home roast - hitting group head screen
Occasionally the puck will stick to the screen instead of coming out with the basket. I've had certain baskets where that happened (more with a single basket that has such an extreme taper than with a double). I use a third party basket that doesn't taper as much as the stock basket did and I never have the puck stick. I have another machine with straight walled baskets (no taper at all) and it not only doesn't stick to the screen, it is hard to knock the puck out of the basket.
I suppose the extra CO2 nature of the fresh roast could easily be contributing to the sticking ... see if it changes after 4-5 days post roast.
I wouldn't worry about how dry or soupy the top of the puck is - sometimes mine are dry, sometimes they have a puddle on top. The higher dose will compress more tightly against the screen when it swells (and the pour will be slower if it compresses hard against the screen) and the puck will usually be drier afterwards - slightly lower dose may leave a little space and a little wetness on top but I don't find that is a problem for me, I just tip the PF over the sink and drain the liquid before I knock the puck out.
I am a bit of an oddball around here in that I sometimes like to dose only 12-14 grams (most go 18+) and when I dose that low there is almost always liquid puddled on top of the puck.
If the puck keeps sticking, just unlock the PF but hold it in place loosely and blip the brew switch for an instant and the water will push the puck back into your PF .. and it will be wet but easier to clean than having the entire puck stuck to the screen.
germantownrob Senior Member Joined: 2 Dec 2007 Posts: 2,018 Location: Philadelphia Expertise: I love coffee
Espresso: Duetto 3, A Dead Oscar Grinder: Vario-W, Preciso w/Esatto,... Drip: Brazen Roaster: Diedrich IR-1, HT B
Posted Thu Apr 5, 2012, 9:23am Subject: Re: Home roast - hitting group head screen
Fresh roast will expand much more from the co2 out gassing but calms down noticeable by day 3. I find it nearly imposiable to pull a shot prior to 24hrs of rest, normally I wait to at least day 4.
MisterJohnnyT Senior Member Joined: 13 Jan 2012 Posts: 59 Location: S.E. Florida Expertise: Just starting
Espresso: Crossland CC1 Grinder: Compak K3 Touch
Posted Fri Apr 6, 2012, 2:12pm Subject: Re: Home roast - hitting group head screen
Actually, it has been my experience that UNDERdosing is worse than OVERdosing when it comes to the puck sticking to the screen. If you underdose, then the puck stays wet and will result in more of a vacuum when you remove the PF. This vacuum can cause the puck to get sucked up to stick to the screen. If you correctly dose or slightly overdose, then the 3-way valve is able to successfully drain the puck of its excess water, since the expanded puck will be in contact with the screen. When you remove the PF, some air is able to pass through the puck, and this prevents the puck from getting sucked out of the PF.
I don't know if that is the correct reasoning or not, but the final effect is still the same. For me, underdosing = wet puck that can stick to screen. Correct/over-dosing = dry puck that stays in PF.
ewindisch Senior Member Joined: 22 Mar 2012 Posts: 14 Location: PA Expertise: I live coffee
Posted Sat Apr 7, 2012, 8:19am Subject: Re: Home roast - hitting group head screen
Yes, it seems that I was underdosing. I think I also needed to backflush (and have since done so).
Ultimately, the 8-24hr beans do seem to be blooming more than older beans, but dosing more, grinding coarser, and backflushing has definitively helped. They're still light-years ahead of anything I've sourced elsewhere. Hopefully, in a week I'll be ahead of the roast enough that I won't need to worry about this as much. If I fall behind, I'll hit the local roaster... I'm never going back to vacuum-packed ;-)
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