Dear GS3 users

I had a little bit worries to post this new topic, since I am quite an advanced barista, ,
but actually I don't know if it is a GS3 problem or not, thus I thought to share it with you guys.

Since approx 3 month I am observing that I get decent bubbles on the crema on espresso shots.

What have changed since my observation was the new Brita filter which I had before too (annual change & properly rinsed 10L)

Interesting is, that it is not always the same and I observe that it is more linked to lighter roasted coffee.
I normally extract at 93.5°C and brew pressure on the gauge is set at slightly behind 9bar (machine is plumbed to mains). The coffee I am currently using is 30 days old, so it rested quite good.

Could it be there is a restriction in the water flow in order the water jet is coming too fast to the shower screen? Gicleur? I also observe that there is sometimes a kind of whistling sound after the first 10sec.

other details: shower screen IMS MA 200 IM, basket VST20 , dose normally 20g and 34-38 shot weight.

thanks for some hints and best regards
streezz

streezz wrote:The coffee I am currently using is 30 days old, so it rested quite good.
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There is your problem. Old coffee. Try something no older than 14 days, 5 days would be better.

This looks normal to me.
Isn't it just the nature of using a bottomless portafilter? Unless you do something to collapse the crema, such as running the stream down the side of the cup.

If I use the bottomless portafilter I always get bubbles because the espresso drops from pretty high up. When I raise the cup to close the gap then the bubbles disapear. Using a spouted portafilter and rainsing the cup completely eleminates the bubbles. Nothing to worry about.