<p>I have noticed the same thing. I believe it occurs because minute gas particles in the instant coffee, trapped during <a href="https://coffee.stackexchange.com/q/411">the production process</a>, are suddenly released. This gas (air or something inert) rises to the top and bubbles or foams. It dissipates immediately, unlike crema.</p>

<p>I don't think it's caused by any physical chemistry stuff, like heat from dissolution or any actual reaction, though I do notice it more with very hot water. </p>

CC BY-SA 3.0
2016-10-10T11:43:22.273Z
2016-10-10T11:43:22.273Z
2017-04-13T12:51:53.733Z
hoc_age
<p>Both instant coffee and regular ground beans &quot;foam&quot; when pouring hot water over them.</p>
<p>Here you can see a coffee cupping (quality assessment), where they pour fresh off the boil water onto coffee grounds:</p>
<p><a href="https://i.sstatic.net/DeIb7.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/DeIb7.jpg" alt="Cupping" /></a></p>
<p>Most of the gas released during any kind of coffee brewing is the CO2 created during roasting. While brewing filter coffee (in a V60 for example) this initial phase of degassing is called <em>the bloom</em>.</p>
<p>Instant coffee also degases a bit when brewing, here is an extreme example:</p>
<p><a href="https://i.sstatic.net/CThgI.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/CThgI.jpg" alt="enter image description here" /></a></p>
<p>When either of those coffees is left alone for a while all of the trapped gas escapes, similar to a soda which is left open. When the gas has escaped and the &quot;foam&quot; disappeared you cannot create a foam on top again, unless you whisk it really really fast.</p>

CC BY-SA 4.0
2020-09-27T14:56:18.847Z
2020-09-27T14:56:18.847Z
technical_difficulty
<p>I have seen that when preparing coffee without milk (just water and coffee), instant coffee (at least Nespresso) foams when stirring it just a bit. However, regular coffee grounds do not.</p>
<p>Does someone know the reason for this?</p>

<instant>
Why does instant coffee foam when stirring it?
Cristina HG
# Why does instant coffee foam when stirring it?

(Asked by: username_0 on 2016-10-10)

I have seen that when preparing coffee without milk (just water and coffee), instant coffee (at least Nespresso) foams when stirring it just a bit. However, regular coffee grounds do not.

Does someone know the reason for this?

**Tags:** instant


---

## 2 answers

### Answer by username_1 on 2016-10-10. Score: 2 | Accepted answer

I have noticed the same thing. I believe it occurs because minute gas particles in the instant coffee, trapped during [the production process](https://coffee.stackexchange.com/q/411), are suddenly released. This gas (air or something inert) rises to the top and bubbles or foams. It dissipates immediately, unlike crema.

I don't think it's caused by any physical chemistry stuff, like heat from dissolution or any actual reaction, though I do notice it more with very hot water.


---

### Answer by username_2 on 2020-09-27. Score: 1

Both instant coffee and regular ground beans "foam" when pouring hot water over them.

Here you can see a coffee cupping (quality assessment), where they pour fresh off the boil water onto coffee grounds:

[![Cupping](https://i.sstatic.net/DeIb7.jpg)](https://i.sstatic.net/DeIb7.jpg)

Most of the gas released during any kind of coffee brewing is the CO2 created during roasting. While brewing filter coffee (in a V60 for example) this initial phase of degassing is called *the bloom*.

Instant coffee also degases a bit when brewing, here is an extreme example:

[![enter image description here](https://i.sstatic.net/CThgI.jpg)](https://i.sstatic.net/CThgI.jpg)

When either of those coffees is left alone for a while all of the trapped gas escapes, similar to a soda which is left open. When the gas has escaped and the "foam" disappeared you cannot create a foam on top again, unless you whisk it really really fast.


---

