<p>Caffeine is quite stable, it doesn’t evaporate or break down at room temperature (or coffee temperature), apart from dissolving in the water used to brew your coffee. So after an hour or two, the caffeine content is the same<sup>1</sup> as right after brewing. </p>

<p>Unfortunately, the same is not true for some of the other substances that have us appreciate coffee, so you may expect the flavor to deteriorate a bit (or a lot, depending on whether you started with a handful of freshly ground slow-roasted beans or a few spoonfuls of Folger’s coffee-flavored sawdust). But that’s not what you were asking about.</p>

<p>———-</p>

<p><sup>1</sup> If we were <em>really nitpicking</em>, we could even say that the caffeine <em>ratio</em> (not content) increases due to a minute bit of water evaporating during the given time frame. But for the average household precision, “stays the same” is sufficient.</p>

CC BY-SA 4.0
2019-10-04T07:43:31.080Z
Yes, as for the flavour I have noticed a slight decrease in acceptability after an hour :)
Inertial Ignorance
CC BY-SA 4.0
2019-10-04T07:19:27.160Z
2019-10-04T07:19:27.160Z
Stephie
<p>For example, if I let a cup of coffee sit for 1-2 hours, would the amount of caffeine I get mostly be the same? Or does it decrease?</p>

<caffeine>
How much does caffeine concentration in a cup of coffee decrease as a function of time (roughly)?
Inertial Ignorance
# How much does caffeine concentration in a cup of coffee decrease as a function of time (roughly)?

(Asked by: username_0 on 2019-10-03)

For example, if I let a cup of coffee sit for 1-2 hours, would the amount of caffeine I get mostly be the same? Or does it decrease?

**Tags:** caffeine


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## 1 answers

### Answer by username_1 on 2019-10-04. Score: 9 | Accepted answer

Caffeine is quite stable, it doesn’t evaporate or break down at room temperature (or coffee temperature), apart from dissolving in the water used to brew your coffee. So after an hour or two, the caffeine content is the same1 as right after brewing.

Unfortunately, the same is not true for some of the other substances that have us appreciate coffee, so you may expect the flavor to deteriorate a bit (or a lot, depending on whether you started with a handful of freshly ground slow-roasted beans or a few spoonfuls of Folger’s coffee-flavored sawdust). But that’s not what you were asking about.

———-

1 If we were *really nitpicking*, we could even say that the caffeine *ratio* (not content) increases due to a minute bit of water evaporating during the given time frame. But for the average household precision, “stays the same” is sufficient.

> **Comments:**
> **username_0**: Yes, as for the flavour I have noticed a slight decrease in acceptability after an hour :)  

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