Here’s the video of me getting my PhD from UO and my poor adviser having to rangle me into the hood. She said I had to walk and wear robes, she just didn’t specify they couldn’t be over a T.rex costume. #phdchat #ScienceTwitter

The Kyrgyz national park Ala Archa has some new signage! Includes a big sign about outdoors safety. Bit funny that all the way in Central Asia the water bottle is branded @REI though… Guessing it may be a “borrowed” graphic!

Takeaways: There’s a podcast! Coffee Lit. Rev. Adding a tiny bit of water to beans improves flavor. Tiny bit! Electrochemistry can measure the differences that drive the taste differences!

With a large sample of professional tasters found that adding 700mV for 30s greatly improved the flavor! Didn’t really change acidity but greatly increased the sweetness! This applies to things like beer and bourbon too!

Current directly corresponds to the concentration. However where the voltage peak is doesn’t! Bean mass and water mass have a much bigger impact. Then grind setting, temperature, time. Together these can very accurately predict properties of the coffee.

What can you control? Mass of coffee, mass of water, water temperature, immersion time, grind setting.

What does different roasting profile do to coffee? Light roast coffee has more charge being passed early on.

Electrochemistry! Different voltages will attract different compounds! But how does that actually relate to taste? Some families of compounds will respond to specific voltages on inert materials like graphite or platinum.

This is a big deal. (It’s saved Starbucks 300 million dollars!) but more importantly it’s something everyone can do that gets more of the good flavors and less of the bad. Just with a little spray of water to your beans as they grind!

When the coffee is ground it gets static charges. This makes what act as bigger pieces, uneven diffusion. But wait! Spritz a little water onto the whole beans before grinding and the static is gone! This ALSO increases the amount of caffeine in the coffee!

Kyle Ramage, top us barista ranked #4 in the world uses this technique! Frozen beans seem to result in better flavor. But what else contributes to flavor?

The diffusivity for caffeine and other molecules is different. Also the wetting of different size particles will be, well, different. Coffee grinders are bad at making same size particles. Unless it’s frozen! Frozen beans break more uniformly and seem to result in better flavor!

Time matters too! Some molecules quickly reach a max and decrease, others slowly ramp up. So the chemical composition AND the taste change as it brews.

Ok more historic Nobel Prizes! Vant Hoff: 1901, discovery of chemical dynamics. Chemical reactions are often temperature dependent. Cold brew and hot brew have different chemistries and caffeine extraction because of this!

Well… not really. Small amounts of ethanol will produce the same refractivity as salt water. But it could still have good info! Let’s add some other info: extraction yield.

Let’s go back to 1907 Buchner Nobel Prize in chemistry. He discovered cell-free fermentation. He looked at wine, but some of the same principals could apply in coffee! Could refractive indices tell us about flavor?

Water is really important for coffee taste. Especially acidity. Water is never pure, it has dissolved minerals in it. CaCO3 or HCO3 are common, they minimize acid, which is part of the desirable flavors! High mineral content lowers perceived flavors.

4 minute brew time on a cupping table. Water + course ground coffee + four minutes. That’s all you need! (In contrast to the NASA 1.6 million dollar cup, which is cool, slows astronauts to still sip coffee!)

The green beans, the roasting, the water chemistry, the equipment all contribute to the taste. The beans are 50%, roast and water are ~20% each, 10% is the equipment and making.

Coffee is 1.9% of the US GDP!!!! Wow! Filter coffee dominates the US, espresso beverages dominate Europe.

“Flavor notes”. What does that mean? What does that actually mean? How does actual mean?