According to the U.S. Department of Defence,
the best time to drink a coffee is not when you first wake up.
To get the full benefit of caffeine, you need to wait a little bit,
but wait until when? We'll explain right after this...
Hey,
it's Adam Carr here from the coffee science and education center here at Seven
Miles Coffee Roasters. So today we're gonna look at caffeine,
as you can imagine, as a coffee roaster,
we get a lot of questions about caffeine,
how much caffeine is in this particular coffee? What about brewed coffee?
What about espresso coffee? As a chemical engineer myself,
I have a vested interest in how much caffeine is in coffee,
and in the chemistry of coffee more broadly. And as you can imagine,
there's a lot of literature out there that talks about caffeine and its impact
on our lives.
So we dug through that research and we're going to present those findings today.
So what is the ideal time to drink coffee?
The U.S. Department of Defence recommends between nine o'clock and 10 o'clock in
the morning.
The reason being that you get the maximum impact of caffeine in terms of how it
functionally affects you, and you minimize the effect of caffeine on your sleep.
So you get the most possible rest and the best possible energy boost,
lots of other research out there showing that actually the impacts of caffeine
vary based on when you yourself regularly consume caffeine. Also, similarly,
you getting a caffeine headache will depending on how much coffee you regularly
drink and the time of day that you drink it.
So it's reasonably complicated as you'd expect when it comes to anything
interacting with your body, and everyone's body being different.
But that's what the department of defence has to say about it at least.
So how much caffeine is safe to drink?
So the first big finding that we found was from an Australian group of
researchers down in Melbourne,
a group of doctors who had a look at the impact of caffeine.
How many cups of coffee it took to measurably change someone's heart rate?
Cause that is one of the impacts that over consumption of caffeine can have.
And they found that it took at least eight and a half cups of coffee,
espresso level coffee for it to have any kind of appreciable effect on the
heart. It was not measurable up to, and even a little bit beyond that point.
The other way of doing this is to look at the safety data sheets of caffeine.
So to get the equivalent amount of caffeine that you could get from coffee,
to that toxic limit, you need to drink about 25 liters of
filter coffee. As you can imagine, I don't think you'd hold the cup.
So the next question is: does caffeine extract first?
And this is a question that we've had a few times,
or at least it's a statement I've heard a few times in the industry.
We refer specifically to espresso here,
although technically it should hold also for filter coffee. So no,
not specifically caffeine seems to extract consistently across the entire
extraction.
And actually you only extract about 20% of the caffeine available in coffee.
In other words, after you've finished your extraction, both espresso and filter,
you have about 80% of the caffeine still left inside the coffee grounds.
It seems that only about 20% is available to be extracted from coffee.
So while running it longer does increase the amount of caffeine in the cup,
you get it across the entire extraction. So no, it's not extracted first per se.
Does decaf coffee contain caffeine? Yes, it does.
It's as we talked about just before,
it's very hard to remove all of the caffeine from coffee, even with very,
very selective and specific extraction processes. That said,
most decaf coffees contain about between about one and 10% of the residual
caffeine, inside the coffee, again depending on the method.
That's still a lot less caffeine that's available in coffee beforehand,
and actually it's about the same amount as in as in a hot chocolate.
So clearly won't affect you as much as a regular caffeinated coffee or tea
for that matter.
Espresso has a high concentration of coffee, but per serve,
a batch brewed coffee, that is plunger or filter coffee,
because you drink more of it per cup actually has more caffeine in it.
Normally it's comparing about 80 milligrams of coffee and a double shot of
espresso versus about 125 milligrams in a plunger coffee.
The caveat to all this is it all also depends on your recipe and whether you
have Robusta in your coffee and whole host of other things and how much water
you put into the dose. So, you know, it varies quite significantly.
So what it says online,
80 milligrams per double shot may in fact be a hundred milligrams.
It could also be 70 milligrams. It depends quite heavily on your recipe.
So the last question we want to tackle here today is,
what kind of roast style coffee has more caffeine?
Traditionally people say because dark roasted coffee tastes stronger,
it's got more caffeine. I've also heard the opposite where people say,
because it's been roasted darker, the caffeine has been removed from the coffee,
cause it literally chemically destroys it. To the last point first, it doesn't.
Caffeine is what's considered a refractory molecule.
So the amount of caffeine per gram of solids coffee is
identical between light, medium and dark roasted coffee. Secondly,
as far as I've been able to find,
the caffeine content between each of those coffees,
assuming all of the origins are the same for those coffees,
is identical between light, medium and dark roasted coffee.
The solubility of caffeine seems to be unaffected, or very,
very smally effected by the presence of other coffee compounds in there.
For sure, dark roasted coffee does taste stronger.
It has been roasted longer and the material in that coffee is more soluble.
So it is stronger, but not in caffeine.
So I hope this has been helpful. If you know more, if you've got any questions,
if you've got any ideas and discussion points,
feel free to leave some comments below.
We'll also put some links to the research pieces that we found that informed
this work. So until next time see you later.