Rocket Giotto - consistency in successive shots

[tonyden]

I recently got a giotto evo v2 and loving it so far.

I've finally got the hang of milk steaming in small quantities (i.e. for one) but the one thing I just can't work out is whilst I get a great double shot out of the double portafilter. Great crema, taste and extraction...a good shot in 23-25sec.

When I'm trying to extract/brew a 2nd or subsequent round with the same grind setting, looks like the machine is choking and takes close to 45-50 sec to extract the full shot. Taste is still pretty good, but not as fantastic as the first shot in the cup.
I've tried changing to grind to coarser to varying levels but still can't nail it.

any tips on what I'm doing wrong?

[victorgin]

Hi Tony, I've encountered similar before. I'd put it down to half cut beans being in your grinder for the first shot grind... which allows the first shot to pass OK, then the second grind is more fresh with beans carrying more oils and more expansion on the second extraction leading to more pluggy.

Some baristas will discard the first 10 seconds of grind to clear the burrs and then grind for the pf shot. You could adjust the tamp on the second shot if you don't want to waste, but I suspect it may still be slower, even if you dose a little less.

Unfortunately I find myself in the same dilemma as I make two in the morning and guess for the second grind tamp etc.

Regards, vic

[victorgin]

Also, is the top of the puck a bit wet when you remove it from the machine? Does it press firm, or a little spongy? This can help you diagnose if you are dosing too much or little... does it knock out clean?

[herzog]

I was thinking the same as victor. Your first shot of the day has a good proportion of yesterday's grounds.

Subsequent shots are 100% fresh grounds so they brew "tighter".

Dial in the grinder correctly for the follow up shots, and discard a few seconds of grounds first thing in the morning.

[tonyden]

Thanks for the tips
i had a brief go today and noted a bit more consistency between shots
will have another go tomorrow before i call this a success
cheers

[tonyden]

Wow im using lots more beans testing this out but i think you guys were spot in
2 days in getting a lot better consistency

thanks for the advice!

[dumiya]

FWIW I usually grind around 8gms of fresh beans to refresh the retained grinds. This seems to work well. It saves wasting a whole grind.

[Gavisconi007]

Hi Tony, I've encountered similar before. I'd put it down to half cut beans being in your grinder for the first shot grind... which allows the first shot to pass OK, then the second grind is more fresh with beans carrying more oils and more expansion on the second extraction leading to more pluggy.

Some baristas will discard the first 10 seconds of grind to clear the burrs and then grind for the pf shot. You could adjust the tamp on the second shot if you don't want to waste, but I suspect it may still be slower, even if you dose a little less.

Unfortunately I find myself in the same dilemma as I make two in the morning and guess for the second grind tamp etc.

Regards, vic

I think working on a number of seconds of grind time to clear stale grounds could be dependant on the grinder. For example my Elektra Nino needs only a one second purge first thing in the morning- that clears around 5 grams which is more than enough for the Nino to get into fresh grinds. Whereas a Robur or similar may need to clear 40 grams or thereabouts. I would suggest a bit of trial and error rather than relying on a set number of seconds of purge.