13 votes
Accepted

Theobromine in coffee

According to the Dr. Duke's Phytochemical and Ethnobotanical Databases, Coffee Arabica has one of the largest amount of theobromine in its seed (20 ppm). However, this amount is just a bit more than 1/...
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  • 7,593
10 votes
Accepted

Is coffee a solution or an emulsion?

A cup of coffee is definitely a solution, in the sense that it is composed of dissolved solutes. The solvation occurs once water is introduced. While, there is always a limit to how much of a ...
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  • 1,409
9 votes

Is it good to have the "floating oil" on the surface of some coffee drinks?

The amount of oil in your coffee correlates to what is called the "body"? This is the "fullness" that you feel of the coffee in your mouth. Like the difference between a light cake and fudgey brownie. ...
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8 votes
Accepted

Is it good to have the "floating oil" on the surface of some coffee drinks?

Nice question. A similar myth has been arisen for Turkish coffee pot; such as it should be cleaned only with water to keep the greasy surface made with coffee oil. Partly correct, partly not. ...
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  • 7,593
7 votes

Warm Brew Coffee?

Well I'm a chemist, but I can't say I'm an expert at scientific coffee extraction; take what I've got to say with a grain of salt. Whenever you are extracting something into water, the temperature ...
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7 votes

Why do some grounds float and others sink when brewing by pour over

Bean density varies dramatically with roast level. The more roasted a bean is, the less dense it becomes. My guess would be that less dense beans would have more of a tendency to float and more ...
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7 votes

Is black coffee a solution, a colloid or a suspension?

That depends how the coffee is prepared. Coffee prepared via the drip method is typically a solution. You can dilute it as much as you like and will never find suspended solids. Coffee prepared in ...
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  • 1,424
5 votes
Accepted

Is decaffeinated coffee more acidic?

According this source, a study by Dionex, a part of Thermo Fisher Scientific, found that decaf coffee is less acidic than regular coffee. That being said, all coffee causes the stomach to produce ...
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5 votes
Accepted

Does coffee really stunt your growth?

No. That coffee (or caffeine or anything else in coffee) would stunt growth is a debunked myth. Here's an article from the New York Times that cites a small university study that showed no relation ...
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  • 8,507
5 votes

Theobromine in coffee

I suspect the reason is that theobromine is much less soluble in water than caffeine. A forum post is here. Caffeine – 21600mg/L water Theobromine – 330mg/L water So potentially the grounds have ...
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  • 246
4 votes
Accepted

How much "coffee" is there in my cup?

This is discussed in many different contexts many times, I assume. So, I can say not a very strange question in essence. I advise you to check a previous answer first. It includes a very nice chart ...
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  • 7,593
4 votes

Warm Brew Coffee?

There are a few principles involved here (a chemical engineer's perspective on leaching - essentially coffee brewing is just that). As Eli mentioned, solubility in water for most materials increases ...
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  • 41
4 votes

Quantifying flavor differences between varieties?

Sort of... These links, including the redesigned coffee lexicon might help answer your question http://worldcoffeeresearch.org/images/pdfs/WCR_Sensory_Lexicon_Edition_1_2016.pdf https://en.wikipedia....
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  • 400
3 votes

Can I reduce harmful terpenes?

Terpenes are the lipids (oils) that give the main flavor to your cup. Therefore, you don't want to reduce them normally. However, if you really want to reduce them, best choice is, as stated thick ...
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  • 7,593
3 votes

Why do some grounds float and others sink when brewing by pour over

One thing to keep in mind is that coffee beans contain CO2. This causes grounds to float and foam. If the beans don't have any CO2 they won't float. This is also a sign that they have gone stale.
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2 votes

Is stale coffee less healthy for you than fresh coffee?

Disclaimer: Lately, I was checking some unanswered questions. This one stands for a while. So, I decided to use the advantages of sitting in an academic office and sought the academic databases I can ...
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  • 7,593
2 votes

Why do aeropress columns get abrasions, or scars, near the top?

A couple years ago I emailed AeroPress because I had gone through two presses with a similar problem. In my case, the cylinder had developed heavy abrasions that affected the plunger seal. Here's my ...
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2 votes

Why do aeropress columns get abrasions, or scars, near the top?

However I cannot understood the scars definitely, I would like to offer a solution to the scars I thought: There is a possibility that coffee grounds may stick to the rubber ring and scratch the ...
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  • 7,593
2 votes

Could light transmittance be used to timely determine extraction?

Refractometers are widely used to measure the opaqueness of the coffee during brewing to timely determine the extraction time. Spectrophotometers are used to measure color instead of opaqueness. They ...
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  • 7,593
2 votes
Accepted

Using Arabica coffee beans for making instant coffee

The process should be quite the same. At least, according to this wholeseller's website. As far as I understand this company sells 100% Arabica or Robusta OEM instant coffee. For example, the well-...
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  • 7,593
2 votes

What acids are there in coffee?

Funny I should come across this topic tonight, as I'm reading a book right now about the science behind making coffee as a commodity, a beverage and an art form. One particular sentence from the book ...
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2 votes

What acids are there in coffee?

Note: I leave out a lot of the details of espresso shot extraction and just mention the major points of troubleshooting so don't flame me =p Acidity is always tricky when you talk coffee because ...
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  • 1,354
2 votes
Accepted

What type of coffee maker creates the most coffee scent?

If you want a lot of scent, you will want to make sure that nothing stops evaporation - so no lid and a large surface area are paramount. The classic method would be hand-filtered pour-over, which ...
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  • 3,853
1 vote
Accepted

What is the industrial method for extracting caffeine to make decaf?

Caffeine is mostly extracted by utilizing very safe processes. Some of them, such as Swiss water, is not even really a chemical process. Please see the following relevant discussions: Of the various ...
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  • 7,593
1 vote

What type of coffee maker creates the most coffee scent?

I believe coffee lovers consume coffee to be able to drink that smell. I just want to add to Stephie's answer where that smell comes from. While roasting, during Maillard reaction, the little pores ...
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  • 7,593
1 vote

Effects of coffee consumption on testosterone production

In short, caffeine may increase "Sex Hormone Binding Globulin" which results decreased levels of testosterone in both men and women. However, I don't know how effective it is. Or if this decrease is ...
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  • 7,593
1 vote

What acids are there in coffee?

I'm not sure if I have understood the question clearly. I will give it a try. For espresso making, the temperature is not directly controlled by the barista, but by the espresso machine. So, you ...
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  • 7,593
1 vote

Could light transmittance be used to timely determine extraction?

I know it's down a different line (I like the idea of using light though) but the most common way to test proper extraction is to perform a TDS (Total Dissolved Solids) test. This is the industry ...
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1 vote

Warm Brew Coffee?

I think what your idea would lead to a more bitter taste. Simply because it would be very easy to overdo the time needed. If the beans over extracted you would have lukewarm bitter coffee. You would ...
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1 vote

Warm Brew Coffee?

Your hypothesis sounds interesting. Try it. Traditionally speaking though, these factors are what affect the characteristics that you are concerned about: Bitterness - affected by degree of roast. ...
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