Hello!

This is my first post, but I've been reading a lot of home-barista's articles and forums in the last months to understand espresso better and to help me find the perfect tools for my coffee making interests.

I've had the Oscar and Vario combo for a couple of weeks now and I have been steadily using a certain grind to get a 41-42 ML double dose shot with 18g of coffee in 28 to 32 seconds recommended by 49th parallel for the Old School coffee I'm using.

This video gives a good idea on the kind of extraction I've been getting most of the time. While I am by no means an experienced barista, to me it seems that the extraction blonds quite fast and that the coffee isn't evenly distributed in the filter. To my taste buds, the coffee tastes a little bit on the dull side, without much acidity.

Any ideas on what I'm doing wrong and how to improve my shots?

Please note that the Oscar has been modified with:

CO10 valve
Anti vacuum valve
OPV adjusted to 9 bar

Thanks in advance for the help!

I'm not familiar with that particular coffee but after watching the video a couple or 3 times it appears a rather uneven extraction = uneven distribution.

How do the shots taste? Suspect portions of the puck over extracting and bitterness but can't taste a video!

Thanks for the reply!

The shot tastes a bit on the dull side. I wouldn't say that it is bitter, but it's lacking some acidity.

What's the age of the coffee? If less than 13-14 days grinding just a hair coarser = pulling a few seconds faster. If older than 14-15 days the acidity is the first to go... OTH if less than 7 days it may actually be too fresh for it's full flavor potential as a straight shot if a relatively lighter roast but like I said I don't know that coffee.

Hi.

I am not the expert. But here are my thoughts:
I think your distribution can be improved. It looks like there is more coffee in the centre area and less on edges.
So I expect the coffee in the centre might be under extracted and outer perimeter would be over extracted slightly.
If I were you I would try following:
1. WDT or
2. Distribute by horizontal and vertical tapping)
and maybe try slightly nutation move while tamping. This would push the coffee to the edges as well.

ilker wrote: So I expect the coffee in the centre might be under extracted and outer perimeter would be over extracted slightly.

That's exactly what I thought after looking at the video. Wonder if you have some edge channeling going on.

It also looks like low brew pressure. I believe the Oscar uses a vibe pump and setting the OPV to read 9bars is not he way to go. At least that is my experience with my Rocket Giotto. I have to set mine at 10 to 11bar to get the same flavors/texture/aroma I get with my Profitec Pro700(rotary pump) at 9bar.

At 9bar on my Giotto I get results that look just like yours. Watery/fast blonding/multiple weak streams. At least try it and if you don't see a change then just go back to 9bar and good luck.

Compass Coffee wrote:What's the age of the coffee? If less than 13-14 days grinding just a hair coarser = pulling a few seconds faster. If older than 14-15 days the acidity is the first to go... OTH if less than 7 days it may actually be too fresh for it's full flavor potential as a straight shot if a relatively lighter roast but like I said I don't know that coffee.

The coffee is over 15 days old, I'll compare with a fresher roast when I'm done with this bag! Thanks a lot for the input

ilker wrote:Hi.

I am not the expert. But here are my thoughts:
I think your distribution can be improved. It looks like there is more coffee in the centre area and less on edges.
So I expect the coffee in the centre might be under extracted and outer perimeter would be over extracted slightly.
If I were you I would try following:
1. WDT or
2. Distribute by horizontal and vertical tapping)
and maybe try slightly nutation move while tamping. This would push the coffee to the edges as well.

Thank you very much for your advice. I've seen the article about WDT and I'll try it as soon as I can. However, I'm not sure by what you mean in #2. How exactly do I tap horizontally or vertically? Also, by slightly nutation move while tamping do you mean to rotate the tamper after I have tamped the coffee? Thanks

F1 wrote:It also looks like low brew pressure. I believe the Oscar uses a vibe pump and setting the OPV to read 9bars is not he way to go. At least that is my experience with my Rocket Giotto. I have to set mine at 10 to 11bar to get the same flavors/texture/aroma I get with my Profitec Pro700(rotary pump) at 9bar.

At 9bar on my Giotto I get results that look just like yours. Watery/fast blonding/multiple weak streams. At least try it and if you don't see a change then just go back to 9bar and good luck.

Thanks for your observation! I'm not sure yet how to adjust the pressure of the OPV, because I've got the machine with it installed stock. I'll look into it, meanwhile, any ideas? Thanks

The Breed wrote:Also, by slightly nutation move while tamping do you mean to rotate the tamper after I have tamped the coffee?

Search is your friend: Nutation: how to do it right.

When you have time you can also check the following articles:

http://www.baristahustle.com/distribution-for-espresso/
http://www.baristahustle.com/distribution-test-results/
http://www.baristahustle.com/how-to-dis ... y-tapping/