Skip to content

PULSE! #4 – Better Coffee Through Chemistry

coffee with caffeine

Image from Wikipedia with slight modifications

Most coffee-particular people already know that the quality of the water you use is important for good coffee, but a recent paper describes how affecting the specific hard mineral content can have important changes in the relative extraction of specific flavor and strength affecting chemicals in your brew. We discuss the basics of coffee preparation, and the conclusions of the paper.

1:15  Greg throws out a Leeroy Jenkins reference right off the bat. (I guess wait for episode 32.33?)

2:00 the article that prompted this show was “A Chemist Has Uncovered A Secret To Brewing Delicious Coffee At Home” published in Business Insider on Jun 5th, 2014.

2:45 The paper is called “The Role of Dissolved Cations in Coffee Extraction”, by Christopher H. Hendon, Lesley Colonna-Dashwood, and Maxwell Colonna-Dashwood, published in the Journal of Agricultural and Food Chemistry.

3:50 The researcher identified seven chemicals important to the flavor and strength of coffee,  and used density functional theory to calculate the bonding energy between these chemicals and common ions in water that contribute to water hardness.

6:45 one of the chemicals present in Coffee, eugenol, is also present in whisky and other barrel-aged liquors.
16:00  It might be useful to suggest to coffee brewers to use distilled or reverse osmosis water and then add something similar to these brewing salts to the water to facilitate extraction!

18:10  The paper only talks about water with Total Dissolved Solids (TDS) of <300 ppm, which is standard for municipal water supplies, but well or ground water in areas (like our own Phoenix area) can have much more calcium hardness than that.


Links to the music used in this week’s episode:
Intro:  IntroCrying (Return to Olde World)
Outro:  Dreams are Maps – The Wild (Dreams are Maps)

Posted in Chris, Greg, podcast, Pulse!.

Tagged with , , , , , .

Episode 17 – Life, The Universe, and Frogs

episode-17This week on LASER we discuss a realistic computer simulation of a universe, a proposed mechanism for why tin whiskers are destroying our most sensitive computers, and GaInSn liquid metal used to reconnect severed nerves in frogs.

5:00 Our first story is about the story “Astronomers create first realistic virtual universe”   from the Illustris Project.
15:40  By “first realistic simulation”  they probably mean that this is the first simulation that results in a realistic distribution of galaxy types.

16:40  One of the most important thing about this simulation is being able to “see” how galaxies evolve and form and interact with each other, and since it is a computer simulation we are able to look into the past and future.

22:05 maybe eventually we’ll be able to look for distribution of M-class planets.

25:00 after talking about videogames, reddit, minority report, and cutting a five minute discussion on the history of neckbeards ( we finally move onto the second topic…

25:30  Whiskers!!! (

26:45 Whiskers are when a thin single-crystal piece of metal grows (very quickly) out of a metal (most often something used in solder or semiconductor packaging).  This causes problems for electronic devices, where it can short out devices, and has been attributed to taking offline three satellites and one nuclear power plant (specifically places where you can’t go in and fix a part.  This also has taken out many computers that just stopped working for seemingly no reason).

28:15 Lead-free solders are especially prone to this problem, because they often contain Tin.  We would prefer to use lead-free because of the environmental and health effects, but it is–so far–the most reliable available solder, based on whiskers and microcracking.

34:50  The paper is  V. G. Karpov, “Electrostatic Theory of Metal Whiskers” Phys. Rev. Applied 1, 044001 – Published 15 May 2014. doi:10.1103/PhysRevApplied.1.044001

37:00 the proposed mechanism for whisker buildup is charge differences on the surface, that are centered around defects.  This extra energy might give the metal the energy it needs to grow directly out.

44:40 Now we’re talking about Liquid Metal nerve grafts in frogs!
and the paper freely available on the arXiv:

The researchers have used a GaInSn liquid metal to connect severed nerves in frogs, and it resulted in connectivity similar to a healthy nerve, allows for the nerves to grow back, and is easily removed once it is no longer necessary.

55:00 fun prank for dinner parties: cast spoons out of low-temperature melting metals, and give them to your friends to stir their coffee. The spoon will melt in their drink, likely poisoning them! (not a fun prank.)


Links to the music used in this week’s episode:
Intro:  Luv Rulez (Original version of ES)Crying (Return to Olde World)
bumper music: Vacation – Crying
Outro:  Dreams are Maps – The Wild (Dreams are Maps)

Posted in Chase, Greg, podcast.

Tagged with , , , , , , , , , , , .

Episode 16 – Sun & Surf

For our first episode of the summer on LASER: Let’s Agree Science & Engineering are Rad, we discuss our own Chris’ recently-accepted paper about inorganic ZnS window layers on organic solar cells.  These increase the efficiency, and help protect the cell from environmental damage.   We then talk about the NRL Press release describing long-chain hydrocarbon fuel (jet fuel) they have made by extracting CO2 and Hydrogen from seawater!

4:00 We’re all back from traveling for work and conferences, finals are done, and Chris just finished his qualifying exams, so we’re back to podcasting, even if we are a little rusty.

6:00 Our first paper is somewhing Chris just got accepted into Journal of Applied Physics, and it is titled “Efficient ZnS cathode layers for orgnaic photovoltaic applications via n-type doping.”

They are using an inorganic material, ZnS to replace the very sensitive organic cathode (top) layer in organic photovoltaics.  Since the organic components are very sensitive to temperature and air, an inorganic cathode can protect the bottom layers.

At the time we’re putting this episode out, the paper isn’t available online yet, but it will eventually be available at

32:30 We discuss the recent press release from NRL (  describing fuel made from CO2 and Hydrogen that was extracted from seawater.  There are a number of press articles about this: Discovery ( Business Insider ( and Inhabitat ( are a few.

38:00 Removing Co2 from ocean water *might* have a small local effect reducing ocean acidification, but because the end result is burning a hydrocarbon fuel, it will end up just going back into the atmosphere and back into the oceans.



Links to the music used in this week’s episode:
Intro:  Luv Rulez (Original version of ES)Crying (Return to Olde World)
bumper music: Vacation – Crying
Outro:  Dreams are Maps – The Wild (Dreams are Maps)

Posted in Chase, Chris, podcast, Sivan.

Tagged with , , , , , , , , , .

LASER Pulse! #3 – The Heartbleed

This week’s LASER Pulse! is about the Heartbleed computer vulnerability.   We cover the basics of the heartbleed bug, why its important, and mention that you really need to CHANGE YOUR PASSWORDS.  Because this is a Pulse episode, there are little to no edits (just the intro and outro really), and the whole show is only about 20 minutes.


No real show notes, just a list of a bunch of links if you want to know more.

Here are links to Sam’s Blog and her Twitter.

  • Our Guest, Samantha, wrote about “Heartbleed for people who don’t know computers good (and want to learn to do other stuff good too)”
  • XKCD Has a great basic explanation in comic-form
  • This Video is the most high-level description of the bug I could find. It is really neat.
  • Here is a link to the first program that allowed millions (maybe more) of people to to gather as much secure data as possible.  It probably won’t work anymore since most servers should be patched by now, but if you have your own server you can install the old version of OpenSSL to test it out.
  • Most importantly, THIS LIST is the list of major passwords that you need to change RIGHT NOW.  It doesn’t include small websites, and if you used the same password on any two sites, they are now both compromised!
  • Don’t think hackers aren’t smart enough to write programs to try the same password, username, and email addresses on even websites that weren’t affected by this! Even if you use small variations of your password, it makes it much easier to crack if someone has part of it.

Be safe online!



Posted in podcast, Pulse!.

Tagged with , , , , , .