Correlation between Crema and Shot Quality

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gene

Correlation between Crema and Shot Quality

Post by gene »

Just cleaned my S1 over the weekend. My wife says shots much improved. But.....could swear have less crema this week than last week. Using Kenya Kianamui Kirinyaga roasted few days ago to C+ and Eth Jimma-Nigusie Lemma roasted
a few days ago perhaps 30 seconds darker. I know both coffees rock.
Using standard double portafilter. Tamp routine is the same. New Cafelat tamper with slight nutation and 15# finish. Approx 1.7 oz in 35 sec with 8 sec preinfusion using 93 Centigrade. Realize if had bottomless would naturally get more crema but seems like I have less this week after I cleaned it.

What really puzzles me is everyone really buzzes about crema so much I thought there must be a direct correlation between lots of crema and god shots. No?

Its not coffee because this is best coffee I have ever roasted.
C'mon give me some tips in using S1 design to its fullest potential!
I know, I know taste test. But with my limited olfactory capability and poor taste buds just fishing for generalities from everyone.

I want to improve but am at a loss as to what to try next. 92C seams to yield sour SO shots. 95C seems to bring out too much bitterness. 93C seems to be a happy medium.
Thanks,
gene
symbology

Re: Correlation between Crema and Shot Quality

Post by symbology »

Has your brew pressure dropped at all? Changed water source?

If the shots are good..........
gene

Re: Correlation between Crema and Shot Quality

Post by gene »

Haven't noticed brew pressure. I'll chart for next week and see if anything changes. With gauges being down there out of the way while shot is pouring I'm usually too busy steaming. I'll change that routine.

Any other ideas just let me know. I'll do anything to get better!
Thanks
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jbb
God Shot
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Re: Correlation between Crema and Shot Quality

Post by jbb »

What's the rationale for why a bottomless PF should yield more crema? Never noticed this myself I guess. Maybe even the opposite.

For my 2 cents, crema production means you're performing the extraction under conditions that have the potential to solubilize the volatile compounds responsible for great espresso. but, depending on the coffee and barista skills (oh still so far to go in my case), they may or may not be there. so, I'd say the correlation is not tight. rather, its an indication of potential but is not in and of itself a sufficient condition. if your flow rate is in the right ballpark, i think absence of crema is typically supposed to mean stale beans or low pressure. but maybe its possible to have very low CO2 content roasts that don't produce much crema but that still produce good extractions. like said above, how do they taste in your 93 C strike zone?
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slo
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Re: Correlation between Crema and Shot Quality

Post by slo »

Here is my Canadian cent worth:

Crema production is more related to the coffee origins and the coffee varietal and also to coffee freshness.

Some beans just generate more crema, along with less body. This is the case of the specific Eth Jimma-Nigusie Lemma that Gene is using right now. t has very thin body and very little crema yet it taste nice.

Coffee bean type is important as well. A robusta or a blend containing robusta will always produce more crema. Although that crema tend to be with bigger bubbles and being less stable (does not last as long).

Finally, freshness: The first few days the gas release is so strong that some of the bubbles will be big and crema will be huge. It will not be as stable. After a few days the crema will become more uniform in bubble size and dense as well as long lasting. Finally after a few weeks the crema will will reduce and become more thin to almost non-existent.

It is true that a fast flowing shot will have a thin crema but that would not be an indication of shot quality in itself because it is possible to have a perfectly flowing shot that has relatively thin crema. It could be an indication when taken in reference with the previous shot that ran in the proper time.

A spouted P/F tends to reduce the resulting crema in the cup by retaining some of it in the spouts and also by breaking some of the bubbles by contact with the metal surfaces, liquid and solids that the bubbles will contact while inside the P/F. But this reduction is not huge in percentage of volume.

This is only my opinions...

Sylvain
Vivaldi II, Multiple (a collection really) Lever machines
Currently on deck grinders: Mythos and MXKR
Backup grinders: Robur, Major.
Toper Cafemino Electric and Poppery 1 roaster

I have a serious problem ... Can you guess what?
gene

Re: Correlation between Crema and Shot Quality

Post by gene »

Brew pressure this AM is a perfect 9 bar.
Little crema with Eth Jimma but wife was complimentary this AM says shot was very good.

I don't want it to be good.....I want it to be great!

I still enjoy the discourse re crema affecting shot quality. It is tiny, tiny tidbits of feedback that is going to be my salvation.
Had a team from Indiana State Univ at my table this weekend. Yesterday rep from Civilian Conserv Corps in Mississippi.
Have New York State Univ Architecture Dept coming this Spring and more universities this Summer. US Olympic paddling hopefuls here in Aug.
And my VISTA just graduated from San Francisco State Univ-not a coffee fan but I hope to change that.

These folks first ever taste of fresh roasted.....had to give a long discourse on the process this week.....I have LOTS OF PRESSURE to improve.
SLO's answer above is great as is some of your suggestions..C'mon JohnB, Endo and the rest of you....need you to chime in!

Thanks,
gene
oton

Re: Correlation between Crema and Shot Quality

Post by oton »

When you say "I could swear have less crema this week than last week. " You mean with the same roasted coffee batch? Although I think you know it, coffee looses crema as times passes.
Endo

Re: Correlation between Crema and Shot Quality

Post by Endo »

Watch this video. You might think differently about crema afterwards:

http://www.jimseven.com/2009/07/06/video-1-crema/
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jbb
God Shot
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Re: Correlation between Crema and Shot Quality

Post by jbb »

Thanks Sylvain.
slo wrote:A spouted P/F tends to reduce the resulting crema in the cup by retaining some of it in the spouts and also by breaking some of the bubbles by contact with the metal surfaces, liquid and solids that the bubbles will contact while inside the P/F.
I guess I was thinking that the increased surface area of the long extended mouse tail with the naked PF would reduce crema volume by speeding up gas diffusion (and maybe cooling) during the shot....but maybe the flow is just too fast for it to matter. I know there are discussions I've read where some definitely prefer shots from traditional spouts, but can't remember the logic as to why that is. The naked PF show sure is fun to watch though.
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slo
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Re: Correlation between Crema and Shot Quality

Post by slo »

jbb wrote:I know there are discussions I've read where some definitely prefer shots from traditional spouts, but can't remember the logic as to why that is. The naked PF show sure is fun to watch though.
I cannot say that I notice a taste difference with spout or without. That is, if the spouts are at the right temperature. If the P/F is cold the coffee will cool excessively. But again some prefer their espresso after it has cooled a bit... It is all a matter of taste as too which is best.

Which brings me to...
Endo wrote:Watch this video. You might think differently about crema afterwards:
Endo, come on! Some pseudo guru says that HE likes it better without the crema and now the crema is bad? Maybe he should just adjust his shots to get an appropriate extraction and stir the crema into the espresso like it is supposed to be. Maybe the Coffe collective coffee makes really bad crema? Even if 10 000 people would tell me that crema taste bad it would not change my mind over it. It could prompt me to try it if I hadn't done so thousand of time before...

I know people that skim the crema off to sip it alone and almost leave the liquid part there because it is the crema taste and feel that they like. I am not one of them, I stir in the crema and sip everything.

Sorry for loosing it...
Vivaldi II, Multiple (a collection really) Lever machines
Currently on deck grinders: Mythos and MXKR
Backup grinders: Robur, Major.
Toper Cafemino Electric and Poppery 1 roaster

I have a serious problem ... Can you guess what?
Endo

Re: Correlation between Crema and Shot Quality

Post by Endo »

slo wrote:Endo, come on! Some pseudo guru says that HE likes it better without the crema and now the crema is bad? Maybe he should just adjust his shots to get an appropriate extraction and stir the crema into the espresso like it is supposed to be.
I don't think I'd try telling him how to adjust his shots correctly (since he is the 2007 World Barista Champion), but I can't say I totally agree with his comments either. For example, mouthfeel is an important component as well. Still, it's good food for thought.
oton

Re: Correlation between Crema and Shot Quality

Post by oton »

Hoffmann isn't a pseudo-guru or a charlatan. His blog is great and his roastery -Square Mile Coffee- is great too. His comments about crema and blog comments are made to make people thinking; Hoffmann don't apart the crema in his shots, but -as he say- crema does not mean a good shot. You can pull a shot with a beatifull crema and however taste awful; I think he's trying to minimize the importance to the crema to contrarest the "crema buzz" that you can read in the forums .
gene

Re: Correlation between Crema and Shot Quality

Post by gene »

"I think he's trying to minimize the importance to the crema to contrarest the "crema buzz" that you can read in the forums"
Thanks Oton, that is precisely why I started this thread. To get to the bottom of this. I have had shots with relatively little crema that taste great. Wanted to see if what I have been reading on all these sites is just pure bunk re all this glorifying crema.

Actually I have found my real problem last few days. Has nothing to do with crema. I have been overdosing the double basket. This morning, even with 15.3 G still seeing faint bolt head marks on the puck as I dump it. But the taste has improved by a huge margin as I have gone from 16.4 to 5.9 to 5.5 and prob 5.0 tomorrow. Whew the S1 seems so ultra sensitive to dose.
gene
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slo
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Re: Correlation between Crema and Shot Quality

Post by slo »

Endo wrote:I don't think I'd try telling him how to adjust his shots correctly (since he is the 2007 World Barista Champion), but I can't say I totally agree with his comments either. For example, mouthfeel is an important component as well. Still, it's good food for thought.
It may very well be good food for thought but it is still a matter of taste... I was a bit abrupt yesterday in referring to a pseudo-guru and I certainly did not imply a charlatan. My reaction was intended toward the message not the messanger. Nonetheless, I doubt that he won the championship with skimming the crema. For that matter as anyone won any contest after skimming the crema off an espresso?

What I dislike the most was the statement that the crema does not taste good and that espresso is better without it. There was no expression of the possibility that ones tastes (his) are not the same as someone else.

For me the crema is part of an espresso. It is a big part of the visual and tactile pleasure of the experience. Weither it be thin, thick, dark or light it is part of the drink and I will keep it in. YMMV.

P.S.: I did skim the crema off one shot this morning. The taste was clear, fruity and very defined but I still prefered the following shot with the crema which was just more complete (to my preferrences).
Vivaldi II, Multiple (a collection really) Lever machines
Currently on deck grinders: Mythos and MXKR
Backup grinders: Robur, Major.
Toper Cafemino Electric and Poppery 1 roaster

I have a serious problem ... Can you guess what?
Dan Bollinger

Re: Correlation between Crema and Shot Quality

Post by Dan Bollinger »

I think crema is improved with a bottomless PF. Crema is composed of bubbles. Bubbles pop when disturbed by agitation or turbulence. To prove this, just stir a shot with a spoon and watch the crema slowly disappear. A regular PF forces the coffee to flow a convoluted path to the cup, which, I think, causes crema bubbles to pop. Not so with a naked PF.
Endo

Re: Correlation between Crema and Shot Quality

Post by Endo »

I agree. But I'd add that the additonal drop height from the bottomless PF causes more surface disturbance as well.

I get lots of crema. Too much. This is the unfortunate consequence of using very fresh home roasted beans. I get rid of them by tapping down my espresso cup and swirling for about 15 seconds before drinking. For good latte art, you must remove all big bubbles as well. Easy way to do this is to do a big "wine like" swirl of the shot in the latte cup.
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