Crema dissipation

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Crema dissipation

Postby jpscoffee on Sun Apr 05, 2009 1:42 pm

We are having issues with crema dissipation. The shots are pouring (and tasting) anywhere from OK to very good depending on the day, but the crema dissipates way too quickly (anywhere from 30-40 seconds the crema is starting to disappear). And once I take my first sip it seems like when I go to take my next sip the crema is mostly gone. We have toyed with our blend over the last year many times. Adjusted roast profile a bit (gone a little lighter - we use a darker roast), we tried various percentages on the blend, roasted the ingredients separately, brewed them separately and together and in different percentages. It just seems like we continue to have the same issue and I can't seem to identify the reason. I didn't have this issue a year or a year and a half ago.

A quick rundown on variables:
Blend - Brazil, Guat, Sumatra
Aging - we are aging our blend at least 8 days because of freshness bubbles
Machine - issue shows up on both our Rancilio Classe 8 and NS Aurelia - Classe 8 set at 1 atmosphere, Aurelia is only about 3 months old machine.
Water - We have full Everpure High Flow CSR Triple-MC part #9328-05 on the water supply and an Everpure filter just before the machines (QL3 head (9272-12) and ESO cartridge (9607-10)). The ESO is a three stage blending cartridge that softens, buffers, and filters.

Can anyone identify the most common culprits of this problem? Any other facts you might need to diagnose?
Thanks
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Re: Crema dissipation

Postby nick on Sun Apr 05, 2009 7:49 pm

jpscoffee wrote:Blend - Brazil, Guat, Sumatra

No problems inherent to that sort of blend.

Aging - we are aging our blend at least 8 days because of freshness bubbles

How is the coffee stored during these 8 days? "Days off roast" are not all created equal. The conditions under which that coffee is resting is JUST as important as the number of days. 8 days in air-tight bags with one-way valves is a decent rest for espresso. 8 days NOT sealed in a (basically) air-tight environment is probably too many.

Machine - issue shows up on both our Rancilio Classe 8 and NS Aurelia - Classe 8 set at 1 atmosphere, Aurelia is only about 3 months old machine.

Do you have anything to measure the brew temp? If the temp is too high, it will generally yield less crema than otherwise.

Water - We have full Everpure High Flow CSR Triple-MC part #9328-05 on the water supply and an Everpure filter just before the machines (QL3 head (9272-12) and ESO cartridge (9607-10)). The ESO is a three stage blending cartridge that softens, buffers, and filters.

A big red flag here. The type of filter is irrelevant. The resulting water is what's important (TDS, mineral content, etc.). At the very least, get your water tested for TDS. TDS that's too high will generally yield less crema than otherwise.

Can anyone identify the most common culprits of this problem? Any other facts you might need to diagnose?

How much are you dosing? Dosing too little will generally yield less crema than otherwise.
What kind of baskets are you using? Baskets that are too shallow will generally yield less crema than otherwise
What kind of grinder? A grinder with smaller and/or duller burrs will generally yield less crema than otherwise. Also, a grinder that's HOT will generally yield less crema than otherwise.
How dark is your "dark" roast? A darker roast coffee will generally yield less crema than otherwise.
Technique is going to be critical as well. If your dosing isn't fundamentally sound (leading to channeling or unbalanced extractions), it's gonna hurt the crema.

Hope that helps. Remember though... there isn't a huge correlation between quantity of crema and the taste of the coffee.
Nick Cho
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Re: Crema dissipation

Postby Jason Haeger on Sun Apr 05, 2009 10:31 pm

Again, I agree with Nick.

And also, I'd like to add that some of the best espresso I've tasted has been low on the crema scale. Crema is part of espresso, but it's not the most important part by any means. All that's required is that it is present.

But, as has already been pointed out, the lack of its persistence can be indicative of a problem.

I've also found that old green (or poorly stored) can result in less or faster dissipating crema.

I'm not saying your green is old, but this is also a possible reason.
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Re: Crema dissipation

Postby jpscoffee on Mon Apr 06, 2009 4:00 am

Coffee is sealed in 3 layer valve bags and not opened till used. We use approximately 150 lbs. of espresso a week so our issue is making sure coffee is aged enough. We can really tell the difference if we are busier and have to use espresso that is less than 8 days.

We dose approximately 24 grams in a triple basket. Anfim grinder with newer titanium burrs. Baristas are well trained, but we don't see really any major difference between the baristas, my trainers or myself when running shots.

I have a Fluke and have done some testing of my temp, but I don't think I have been extremely scientific in my testing.

I'm not positive of the agtron, but it is maybe around low 30's.

I checked TDS with my TDSTestr 10 and am getting a consistent 170 PPM (it hasn't been calibrated in a while, but that reading confirms what I expected).

One thing I have wondered about comes more from the green side. I wonder if a year's crop could have been affected enough by variables (too much/little rain, sun, different composting techniques or other grower, location or processing variables) that it affects that year's harvest and shows up in something like this.

Today all I know is this: I had a double ristretto this morning and it was excellent! :D

Thanks for the feedback so far, any more thoughts are welcome.
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Re: Crema dissipation

Postby Rodolfo.Ruffatti on Mon Jul 11, 2011 3:35 pm

Are you using 100% arabica blends? In Italy they teach you that you need at least 5% robusta to get cream, don't know if that's another one of their stupid 'tradition' rules or an actual necessity for good crema.
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Re: Crema dissipation

Postby jpscoffee on Mon Jul 11, 2011 3:41 pm

Um, this post is over two years old.
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