How long can coffee last before it's scientifically bad

[victorkhugo]

I don't care about personal opinion, I'm trying to get an answer that's more scientific.

I'm curious:
How long, after it's brewed, can coffee last unrefrigerated before it's chemically bad for you. Not tastes bad, bad for you. Not kill you. Not make you sick. But has negative effects on your body greater than when it was first made.

Thanks,
Alan

 

[clayperez]

I'm quite positive that there are many factors that will contribute to the longevity of brewed coffee. Most notably, the quality of the water, the roast of the beans, the type of brew, and the storage conditions.

Scientifically this is a very difficult thing to answer because there are so many variables involved. Each person's own brewing techniques will yield different results.

The typical filtered brew in the office breakroom will not keep for more than a couple of hours because it is constantly heated. Whereas cold-brewed coffee, under the right conditions, can keep refridgerated for up to a week or longer.

I advise doing a search on the internet for studies on PH balances and coffee acidity levels, as there are hundreds of pages of information dedicated to scientific research on the subject. But each one will tell you something different - because each one used different brewing techniques.

Good luck on your quest.
Regards,
Carlos

 

[Guest]

I'm still looking, but here are my conditions:

Pre-ground Costco coffee
Brewed in Quisinart - Thermos style (The caraf is heavily insulated, and keeps it warm and is not heated from an outside source)
Not refrigerated

Any ideas on how long based on these factors?

 

[javahill]

This sounds like a question the Car Talk guys would call bo-gus!

The question is - at what point after brewing does coffee have negative effects worse for your body than when it was first brewed. That suggests coffee has negative effects when it is first brewed.

What are the negative effects of freshly brewed coffee? Aside from bad taste of cheap coffee? A lot depends on the condition of the person drinking it. There is a lot of small print. OK - not counting the effects of boiling hot coffee poured on laps of people exiting drive-up windows. Not counting people who have over-caffeinated. Not counting people with heart problems, pace makers, pregnant women, and the usual roller coaster disclaimers. OK and let's not count people who drown in the stuff -or who, like guy who doesn't know how to the proper technique for eating a pretzel, chokes on it.

At what point does coffee become bad for "normal" people under "normal" conditions?

You've got issues with oxygen contamination - but that just makes it stale and eventually bitter. High grown arabicas hold up better.

You've got contamination issues to deal with - that depends on the environment and how clean the container was before coffee was put in.

Coffee is an astringent, so you're not going to get a lot of things growing in it for a while. But that eventually happens.

Based on coffee cup experiments over vacation, I think when little blue islands start floating on top is when there might be negative effects. Granted, I've never consumed coffee with little blue islands floating on it, but it does happen. So I'd say within 1-2 weeks (more/less depending on contaminants, environment, humidity, temperature, etc.) there is a high potential of negative effects.

But if you drink coffee for the coffee instead of for the great cause of science, you want to drink it within 20 minutes of brewing, especially if it is on a heat source like a burner. If it is in a pre-heated airpot or Thermos, you can get a good 60-90 minutes out of it. Less if you start drinking it - because you get cold air coming in.

If you toddy brew good coffee (high grown arabicas) and store it cold, you can get much more time.

This year, the Ig-nobel prize was awarded to a woman who validated the 5 second rule

http://www-tech.mit.edu/V124/N41/41_ignobels.41n.html

Maybe next year, you can try for an Ig-nobel prize of your own on this subject.

 

[Guest]

I'm still looking, but here are my conditions:

Pre-ground Costco coffee
Brewed in Quisinart - Thermos style (The caraf is heavily insulated, and keeps it warm and is not heated from an outside source)
Not refrigerated

Any ideas on how long based on these factors?