
How Pure Is This Cup of Joe? - szczys
https://hackaday.com/2017/11/06/how-pure-is-this-cup-of-joe-coffee-conspiracy-and-citizen-science/
======
gwern
> Finally, I used LibreOffice to tabulate and graph the data, and perform
> t-tests. T-tests are simple statistical tests used to determine the
> probability that a null hypothesis (H0) is correct. If it is less than 5%
> probable that the null hypothesis is correct given our data, we will reject
> the null hypothesis and consider our alternate hypothesis (HA) to be
> correct.

Obligatory stats nerd: that's not what a p-value means, that reverses it.

~~~
xapata
Reverse isn't the right word here, either. Better to restate the definition:
the p-value is the probability of observing the data (as represented by its
aggregate statistics), under the condition of the null hypothesis.

~~~
gwern
I say 'reverse' because that's what it is formally: confusing P(data|null)
with P(null|data). It reverses the conditional probability.

~~~
xapata
Reversing the arguments of the conditional probability, yes, but just saying
"it's the reverse" is a bit ambiguous.

> If it is less than 5% probable that the null hypothesis is correct given our
> data, we will reject the null hypothesis and consider our alternate
> hypothesis (HA) to be correct.

You could be reversing the 5% to 95%, could be reversing null hypothesis to
alternate hypothesis, could be reversing reject to accept, etc. Too many
moving parts. P-values are so often misinterpreted, it's best to err on the
side of specificity.

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shill
Does anyone know what the fish oil additive is used for?

I was recently researching how Trader Joe's coffee is so inexpensive and found
some reviews noting a "fish sauce" flavor and a "fishy" flavor in two TJs
coffee products.

[https://www.thrillist.com/culture/best-trader-joe-s-
coffee-t...](https://www.thrillist.com/culture/best-trader-joe-s-coffee-
tasted-and-ranked-by-toby-s-estate-experts)

------
BugsJustFindMe
[edit] Here's a photo of the back of a bag of his "reference" Trung Nguyen S
blend. It explicitly says that it has flavorings in it, including "coffee
flavor". Omfg.

[https://imgur.com/a/KeSYq](https://imgur.com/a/KeSYq)

\---

I guess the guy had fun, but the conclusion is a few giant leaps away from the
actual results. Many of his decisions and assumptions were entirely arbitrary,
not well substantiated, and lacking just about anything approaching rigor.

His _reference coffee_ is "A blend of Arabica, Robusta, Chari (Excelsa) and
Catimor beans"[1], roasted in a special style, and brewed in one particular
way with no mention of temperatures involved or any other variable that alters
the outcome of brewing coffee.

Trung Nguyen coffees are as far as I know usually adulterated with chocolate
and other flavoring either during or after roasting. This is not a bad thing.
It smells and tastes goddamn fantastic and they are my favorite coffees in the
world. But it's not exactly a good reference.

His _reference chart_ includes only two of those bean types and specifically
references green beans, not roasted beans, not butter roasted beans, and not
beans roasted at any particular range of temperatures or durations.

He doesn't indicate that a _reference coffee_ was chosen based on lowest
wholesale cost, which might have been a reasonable decision factor for a
street vendor, but rather just that it seems to be commonly available on the
consumer market without regard for composition or lack of monopoly.

His _reference not-coffee_ is only one of plausibly dozens of different not-
coffee substances.

His _reference not-coffee solution_ is based on approximately tasting like
terrible coffee. Whaaaaaat.

And even if you choose to ignore any or all of the above, nothing about his
method tests for _coffee_. Coffee is generically an extremely complex blend of
varying volatile compounds, but specifically it is an infinity of different
complex blends of varying volatile compounds. And his process doesn't actually
test for any of them. It tests for some secondary characteristic that one
mixture possesses, ability to change the color of iodine, but that one
arbitrarily different other chemical does not possess to the same degree under
the assumption that all real coffee changes the color of iodine the same and
that all non-coffee also changes the color of iodine the same. These are
exceptionally ridiculous assumptions.

[1] [http://www.trung-nguyen-online.com/trung-nguyen-coffee-
order...](http://www.trung-nguyen-online.com/trung-nguyen-coffee-order.php)

> _Overall it sounds like a reasonable test for the amount of coffee in
> something_

No, it really does not.

This is what happens when people think that "science" is synonymous with
measuring shit.

~~~
justesjc
Why stomp all over somebody's fun? I enjoyed reading it.

~~~
BugsJustFindMe
Because awareness of the gap between measurement and conclusion might just be
the most important thing in the world, and people and governments fail
spectacularly at it all the time with significant lasting effects on society.

~~~
justesjc
> the gap between measurement and conclusion might just be the most important
> thing in the world

What happened to love, compassion and humility?

~~~
smallnamespace
Trying to get to the factually right conclusion is an expression of humility,
because it allows admitting that our initial expectations were wrong.

Using the right conclusion to properly guide our actions is necessary for
compassion and love -- if you truly with to benefit others, then your actions
must be correct and guided by the right answers.

The challenge is updating other people's beliefs without being seen as an
attack.

------
coconut_crab
I thought the rumour here says that the fake coffee is made of roasted soybean
(to add bulk), quinine (bitter), gelatin (thickness), not ready made
artificial flavourings as was tested in the article. Although I highly doubt
that there is no coffee content in street vendor shop, as it doesn't make
sense financially (Vietnam is the 2nd largest coffee producer), so the rumour
is the same as "Chinese plastic rice" or "Chinese fake eggs" IMO.

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pasbesoin
Need to read the article, but after recent occasional experiences with an
associate's, I've been wondering whether the flavor profiles I experience with
K-cup coffee servings are due to flavoring agents. The flavors have that kind
of uniformity and intensity. And I am rather suspicious of their coming from a
package of pre-ground coffee with a shelf life of months or years and
manufactured/sold at the price point their are finding.

------
trisimix
You should test the major chain coffees

~~~
bhouston
I wonder what McDonald's uses to flavor their coffee. In Canada it has a very
distinct taste unlike any coffee I've had. It can not be pure coffee in my
opinion.

It claims it is 100% Arabica beans but it is so consistent and distinct. I
wonder I fit does the 100% pure orange juice "trick" by processing parts of
the Arabica beans into flavor chemicals and reading it.

