<p><strong>The CO<sub>2</sub> stuck within coffee grounds produce the crema.</strong> At least, it is the main substance that forms the crema along with other minor components.</p>

<p>This is a very classic problem -and thus a question.</p>

<ul>
<li><p>If you consider roasting, darker roasts have more crema as they contain more CO<sub>2</sub> as the product of <a href="https://en.wikipedia.org/wiki/Maillard_reaction" rel="nofollow noreferrer">Maillard reaction</a>. Here is a <a href="https://coffee.stackexchange.com/questions/2172/quantifying-flavor-differences-between-varieties/2550#2550">proposed previous post to be read</a>. You may also want to check <a href="https://coffee.stackexchange.com/questions/3735/understanding-coffee-bean-names-as-they-relate-to-roast/3738#3738">this previous post</a> as it may lead to more reading on other metrics you may consider.</p></li>
<li><p>Grind has some effect, but limited. You may see the factors that effect crema production in espresso in this <a href="https://coffee.stackexchange.com/questions/2867/what-factors-influence-crema-production-in-espresso">proposed previous post to be read</a>.</p></li>
<li><p>As you have mentioned, time has a crucial importance. I think this should be your main consideration and you should focus on fixing this first. Basically, <strong>fresh coffee has more crema, always</strong>. You can read a lot more <a href="https://coffee.stackexchange.com/questions/3323/how-long-does-it-take-coffee-beans-to-degas">in this previous post</a>.</p></li>
</ul>

CC BY-SA 4.0
2018-10-01T09:12:15.970Z
2018-10-01T09:12:15.970Z
MTSan
<ol>
<li><p>What produces more crema when extracting espresso, darker or lighter roast?</p></li>
<li><p>What produces more crema when extracting espresso, finer or coarser coffee grind ?</p></li>
<li><p>why am I getting a very thin layer of crema when pulling a SINGLE shot, although the extraction time is 20 sec, the pressure is correct as per the manufacturer of the espresso machine (Breville Barista) I have, and the coffee beans were roasted two weeks ago?! what is wrong?</p></li>
</ol>

CC BY-SA 4.0
2018-10-01T09:17:41.943Z
I feel like these questions have been asked a bunch of times before.
https://coffee.stackexchange.com/questions/2867/what-factors-influence-crema-production-in-espresso
https://coffee.stackexchange.com/questions/9/what-factors-affect-espresso-crema
avocado1
CC BY-SA 4.0
2018-10-05T10:42:13.897Z
Have you tried some robusta beans?
Edoardo
<espresso><brewing-process><crema>
What produces more crema?
Anis
# What produces more crema?

(Asked by: username_0 on 2018-10-01)

1. What produces more crema when extracting espresso, darker or lighter roast?
2. What produces more crema when extracting espresso, finer or coarser coffee grind ?
3. why am I getting a very thin layer of crema when pulling a SINGLE shot, although the extraction time is 20 sec, the pressure is correct as per the manufacturer of the espresso machine (Breville Barista) I have, and the coffee beans were roasted two weeks ago?! what is wrong?

**Tags:** espresso, brewing-process, crema

> **Comments:**
> **username_1**: I feel like these questions have been asked a bunch of times before. https://coffee.stackexchange.com/questions/2867/what-factors-influence-crema-production-in-espresso https://coffee.stackexchange.com/questions/9/what-factors-affect-espresso-crema  
> **username_2**: Have you tried some robusta beans?  

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## 1 answers

### Answer by username_3 on 2018-10-01. Score: 3

**The CO2 stuck within coffee grounds produce the crema.** At least, it is the main substance that forms the crema along with other minor components.

This is a very classic problem -and thus a question.

* If you consider roasting, darker roasts have more crema as they contain more CO2 as the product of [Maillard reaction](https://en.wikipedia.org/wiki/Maillard_reaction). Here is a [proposed previous post to be read](https://coffee.stackexchange.com/questions/2172/quantifying-flavor-differences-between-varieties/2550#2550). You may also want to check [this previous post](https://coffee.stackexchange.com/questions/3735/understanding-coffee-bean-names-as-they-relate-to-roast/3738#3738) as it may lead to more reading on other metrics you may consider.
* Grind has some effect, but limited. You may see the factors that effect crema production in espresso in this [proposed previous post to be read](https://coffee.stackexchange.com/questions/2867/what-factors-influence-crema-production-in-espresso).
* As you have mentioned, time has a crucial importance. I think this should be your main consideration and you should focus on fixing this first. Basically, **fresh coffee has more crema, always**. You can read a lot more [in this previous post](https://coffee.stackexchange.com/questions/3323/how-long-does-it-take-coffee-beans-to-degas).


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